Merge pull request #74 from bakic/service-provider-interface

Service Provider Interface

aws/cdk/.mvn/wrapper/MavenWrapperDownloader.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2007-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import java.net.*;
+import java.io.*;
+import java.nio.channels.*;
+import java.util.Properties;
+
+public class MavenWrapperDownloader {
+
+    private static final String WRAPPER_VERSION = "0.5.6";
+    /**
+     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
+     */
+    private static final String DEFAULT_DOWNLOAD_URL = "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/"
+        + WRAPPER_VERSION + "/maven-wrapper-" + WRAPPER_VERSION + ".jar";
+
+    /**
+     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
+     * use instead of the default one.
+     */
+    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
+            ".mvn/wrapper/maven-wrapper.properties";
+
+    /**
+     * Path where the maven-wrapper.jar will be saved to.
+     */
+    private static final String MAVEN_WRAPPER_JAR_PATH =
+            ".mvn/wrapper/maven-wrapper.jar";
+
+    /**
+     * Name of the property which should be used to override the default download url for the wrapper.
+     */
+    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
+
+    public static void main(String args[]) {
+        System.out.println("- Downloader started");
+        File baseDirectory = new File(args[0]);
+        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
+
+        // If the maven-wrapper.properties exists, read it and check if it contains a custom
+        // wrapperUrl parameter.
+        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
+        String url = DEFAULT_DOWNLOAD_URL;
+        if(mavenWrapperPropertyFile.exists()) {
+            FileInputStream mavenWrapperPropertyFileInputStream = null;
+            try {
+                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
+                Properties mavenWrapperProperties = new Properties();
+                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
+                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
+            } catch (IOException e) {
+                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
+            } finally {
+                try {
+                    if(mavenWrapperPropertyFileInputStream != null) {
+                        mavenWrapperPropertyFileInputStream.close();
+                    }
+                } catch (IOException e) {
+                    // Ignore ...
+                }
+            }
+        }
+        System.out.println("- Downloading from: " + url);
+
+        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
+        if(!outputFile.getParentFile().exists()) {
+            if(!outputFile.getParentFile().mkdirs()) {
+                System.out.println(
+                        "- ERROR creating output directory '" + outputFile.getParentFile().getAbsolutePath() + "'");
+            }
+        }
+        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
+        try {
+            downloadFileFromURL(url, outputFile);
+            System.out.println("Done");
+            System.exit(0);
+        } catch (Throwable e) {
+            System.out.println("- Error downloading");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
+        if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
+            String username = System.getenv("MVNW_USERNAME");
+            char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
+            Authenticator.setDefault(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication(username, password);
+                }
+            });
+        }
+        URL website = new URL(urlString);
+        ReadableByteChannel rbc;
+        rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(destination);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        fos.close();
+        rbc.close();
+    }
+
+}

aws/cdk/.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,2 @@
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar

aws/cdk/mvnw.cmd

@@ -0,0 +1,182 @@
+@REM ----------------------------------------------------------------------------
+@REM Licensed to the Apache Software Foundation (ASF) under one
+@REM or more contributor license agreements.  See the NOTICE file
+@REM distributed with this work for additional information
+@REM regarding copyright ownership.  The ASF licenses this file
+@REM to you under the Apache License, Version 2.0 (the
+@REM "License"); you may not use this file except in compliance
+@REM with the License.  You may obtain a copy of the License at
+@REM
+@REM    http://www.apache.org/licenses/LICENSE-2.0
+@REM
+@REM Unless required by applicable law or agreed to in writing,
+@REM software distributed under the License is distributed on an
+@REM "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+@REM KIND, either express or implied.  See the License for the
+@REM specific language governing permissions and limitations
+@REM under the License.
+@REM ----------------------------------------------------------------------------
+
+@REM ----------------------------------------------------------------------------
+@REM Maven Start Up Batch script
+@REM
+@REM Required ENV vars:
+@REM JAVA_HOME - location of a JDK home dir
+@REM
+@REM Optional ENV vars
+@REM M2_HOME - location of maven2's installed home dir
+@REM MAVEN_BATCH_ECHO - set to 'on' to enable the echoing of the batch commands
+@REM MAVEN_BATCH_PAUSE - set to 'on' to wait for a keystroke before ending
+@REM MAVEN_OPTS - parameters passed to the Java VM when running Maven
+@REM     e.g. to debug Maven itself, use
+@REM set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+@REM MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+@REM ----------------------------------------------------------------------------
+
+@REM Begin all REM lines with '@' in case MAVEN_BATCH_ECHO is 'on'
+@echo off
+@REM set title of command window
+title %0
+@REM enable echoing by setting MAVEN_BATCH_ECHO to 'on'
+@if "%MAVEN_BATCH_ECHO%" == "on"  echo %MAVEN_BATCH_ECHO%
+
+@REM set %HOME% to equivalent of $HOME
+if "%HOME%" == "" (set "HOME=%HOMEDRIVE%%HOMEPATH%")
+
+@REM Execute a user defined script before this one
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPre
+@REM check for pre script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_pre.bat" call "%HOME%\mavenrc_pre.bat"
+if exist "%HOME%\mavenrc_pre.cmd" call "%HOME%\mavenrc_pre.cmd"
+:skipRcPre
+
+@setlocal
+
+set ERROR_CODE=0
+
+@REM To isolate internal variables from possible post scripts, we use another setlocal
+@setlocal
+
+@REM ==== START VALIDATION ====
+if not "%JAVA_HOME%" == "" goto OkJHome
+
+echo.
+echo Error: JAVA_HOME not found in your environment. >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+:OkJHome
+if exist "%JAVA_HOME%\bin\java.exe" goto init
+
+echo.
+echo Error: JAVA_HOME is set to an invalid directory. >&2
+echo JAVA_HOME = "%JAVA_HOME%" >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+@REM ==== END VALIDATION ====
+
+:init
+
+@REM Find the project base dir, i.e. the directory that contains the folder ".mvn".
+@REM Fallback to current working directory if not found.
+
+set MAVEN_PROJECTBASEDIR=%MAVEN_BASEDIR%
+IF NOT "%MAVEN_PROJECTBASEDIR%"=="" goto endDetectBaseDir
+
+set EXEC_DIR=%CD%
+set WDIR=%EXEC_DIR%
+:findBaseDir
+IF EXIST "%WDIR%"\.mvn goto baseDirFound
+cd ..
+IF "%WDIR%"=="%CD%" goto baseDirNotFound
+set WDIR=%CD%
+goto findBaseDir
+
+:baseDirFound
+set MAVEN_PROJECTBASEDIR=%WDIR%
+cd "%EXEC_DIR%"
+goto endDetectBaseDir
+
+:baseDirNotFound
+set MAVEN_PROJECTBASEDIR=%EXEC_DIR%
+cd "%EXEC_DIR%"
+
+:endDetectBaseDir
+
+IF NOT EXIST "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" goto endReadAdditionalConfig
+
+@setlocal EnableExtensions EnableDelayedExpansion
+for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do set JVM_CONFIG_MAVEN_PROPS=!JVM_CONFIG_MAVEN_PROPS! %%a
+@endlocal & set JVM_CONFIG_MAVEN_PROPS=%JVM_CONFIG_MAVEN_PROPS%
+
+:endReadAdditionalConfig
+
+SET MAVEN_JAVA_EXE="%JAVA_HOME%\bin\java.exe"
+set WRAPPER_JAR="%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.jar"
+set WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+set DOWNLOAD_URL="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+
+FOR /F "tokens=1,2 delims==" %%A IN ("%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.properties") DO (
+    IF "%%A"=="wrapperUrl" SET DOWNLOAD_URL=%%B
+)
+
+@REM Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+@REM This allows using the maven wrapper in projects that prohibit checking in binary data.
+if exist %WRAPPER_JAR% (
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Found %WRAPPER_JAR%
+    )
+) else (
+    if not "%MVNW_REPOURL%" == "" (
+        SET DOWNLOAD_URL="%MVNW_REPOURL%/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    )
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Couldn't find %WRAPPER_JAR%, downloading it ...
+        echo Downloading from: %DOWNLOAD_URL%
+    )
+
+    powershell -Command "&{"^
+		"$webclient = new-object System.Net.WebClient;"^
+		"if (-not ([string]::IsNullOrEmpty('%MVNW_USERNAME%') -and [string]::IsNullOrEmpty('%MVNW_PASSWORD%'))) {"^
+		"$webclient.Credentials = new-object System.Net.NetworkCredential('%MVNW_USERNAME%', '%MVNW_PASSWORD%');"^
+		"}"^
+		"[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; $webclient.DownloadFile('%DOWNLOAD_URL%', '%WRAPPER_JAR%')"^
+		"}"
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Finished downloading %WRAPPER_JAR%
+    )
+)
+@REM End of extension
+
+@REM Provide a "standardized" way to retrieve the CLI args that will
+@REM work with both Windows and non-Windows executions.
+set MAVEN_CMD_LINE_ARGS=%*
+
+%MAVEN_JAVA_EXE% %JVM_CONFIG_MAVEN_PROPS% %MAVEN_OPTS% %MAVEN_DEBUG_OPTS% -classpath %WRAPPER_JAR% "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" %WRAPPER_LAUNCHER% %MAVEN_CONFIG% %*
+if ERRORLEVEL 1 goto error
+goto end
+
+:error
+set ERROR_CODE=1
+
+:end
+@endlocal & set ERROR_CODE=%ERROR_CODE%
+
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPost
+@REM check for post script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_post.bat" call "%HOME%\mavenrc_post.bat"
+if exist "%HOME%\mavenrc_post.cmd" call "%HOME%\mavenrc_post.cmd"
+:skipRcPost
+
+@REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
+if "%MAVEN_BATCH_PAUSE%" == "on" pause
+
+if "%MAVEN_TERMINATE_CMD%" == "on" exit %ERROR_CODE%
+
+exit /B %ERROR_CODE%

aws/cdk/src/main/java/com/myorg/SecondStack.java

@@ -0,0 +1,23 @@
+package com.myorg;
+
+import software.amazon.awscdk.core.Construct;
+import software.amazon.awscdk.core.Stack;
+import software.amazon.awscdk.core.StackProps;
+import software.amazon.awscdk.services.s3.Bucket;
+
+public class SecondStack extends Stack {
+    public SecondStack(final Construct scope, final String id) {
+        this(scope, id, null);
+    }
+
+    public SecondStack(final Construct scope, final String id, final StackProps props) {
+        super(scope, id, props);
+
+        String bucketName = (String) this.getNode().tryGetContext("bucketName2");
+
+        Bucket bucket = Bucket.Builder.create(this, "bucket")
+                .bucketName(bucketName)
+                .build();
+
+    }
+}

aws/s3/.gitignore

@@ -0,0 +1,141 @@
+
+# Created by https://www.toptal.com/developers/gitignore/api/java,intellij+all,gradle
+# Edit at https://www.toptal.com/developers/gitignore?templates=java,intellij+all,gradle
+
+### Intellij+all ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+# out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### Intellij+all Patch ###
+# Ignores the whole .idea folder and all .iml files
+# See https://github.com/joeblau/gitignore.io/issues/186 and https://github.com/joeblau/gitignore.io/issues/360
+
+.idea/
+
+# Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-249601023
+
+*.iml
+modules.xml
+.idea/misc.xml
+*.ipr
+
+# Sonarlint plugin
+.idea/sonarlint
+
+### Java ###
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+### Gradle ###
+.gradle
+build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
+
+# # Work around https://youtrack.jetbrains.com/issue/IDEA-116898
+# gradle/wrapper/gradle-wrapper.properties
+
+### Gradle Patch ###
+**/build/
+
+# End of https://www.toptal.com/developers/gitignore/api/java,intellij+all,gradle
+
+# Dumps of the meta-db
+data/*.db

aws/s3/Readme.md

@@ -0,0 +1,167 @@
+<!-- PROJECT LOGO -->
+<br />
+<p align="center">
+    <img src="images/logo.png" alt="Logo" width="200" height="200">
+  <h3 align="center">Private File Upload</h3>
+
+  <p align="center">
+    Build on Spring Cloud & AWS S3
+  </p>
+</p>
+
+
+
+<!-- TABLE OF CONTENTS -->
+## Table of Contents
+
+* [About the Project](#about-the-project)
+  * [Built With](#built-with)
+* [Getting Started](#getting-started)
+  * [Prerequisites](#prerequisites)
+  * [Installation](#installation)
+* [Usage](#usage)
+* [Contact](#contact)
+* [Acknowledgements](#acknowledgements)
+
+
+
+<!-- ABOUT THE PROJECT -->
+## About The Project
+
+<p align="center">
+          <img src="images/usage.gif">
+</p>
+
+
+### Built With
+- Spring Boot
+- Spring Cloud
+- AWS S3
+- ☕️ & ❤️
+
+<!-- GETTING STARTED -->
+## Getting Started
+
+### Prerequisites
+
+In order to run this application you should have an Amazon Web Services (AWS) account.
+
+### Installation
+
+1. Update the `application.yaml` settings value for `cloud.aws.credentials.profile-name` to the name of your local AWS-profile
+2. run `./gradlew bootRun`
+3. Open your browser at `localhost:8080`
+
+<!-- USAGE EXAMPLES -->
+## Usage
+
+The application wraps a lot of S3-related API calls in easy to use UI elements to
+
+- create/delete buckets (mapped as "spaces" so we can give them non-unique names)
+- upload/delete files
+- make files public/private
+- create pre-signed URLs for files
+- create bucket policy rules to set the lifecycle duration for elements
+
+More detailed instructions can be found here:
+
+<details>
+  <summary>🪣 Create a bucket</summary>
+  
+1. Navigate to the _Spaces_ section
+2. Click on _New Space_ 
+3. Enter the name and click _Submit_ 
+4. A message should pop up to indicate success
+
+</details>
+
+<details>
+  <summary>🗂 Upload a File</summary>
+  
+1. Navigate to the _Spaces_ section
+2. Select _Details_ on the target Space/Bucket
+3. Click on _Upload File_
+4. Pick our file, provide a name and click _Submit_
+5. A message should pop up to indicate success 
+</details>
+
+<details>
+  <summary>🔎 List all Objects in a Bucket</summary>
+  
+1. Navigate to the _Spaces_ section
+2. Select _Details_ on the target Space/Bucket
+3. You see a list of all objects stored in the bucket 
+</details>
+
+<details>
+  <summary>🌐 Get an Object's URL</summary>
+  
+1. Navigate to the _Spaces_ section
+2. Select _Details_ on the target Space/Bucket
+3. Select _Download_ on the target object
+4. The object's URL shall be opened in a new tab
+</details>
+
+<details>
+  <summary>📢 Make an object public</summary>
+  
+1. Navigate to the _Spaces_ section
+2. Select _Details_ on the target Space/Bucket
+3. Select _Make Public_ on the target object
+4. A message should pop up to indicate success
+</details>
+
+<details>
+  <summary>🤫 Make an Object private</summary>
+  
+1. Navigate to the _Spaces_ section
+2. Select _Details_ on the target Space/Bucket
+3. Select _Make Private_ on the target object
+4. A message should pop up to indicate success 
+</details>
+
+<details>
+  <summary>🔥 Delete an Object</summary>
+
+1. Navigate to the _Spaces_ section
+2. Select _Details_ on the target Space/Bucket
+3. Select _Delete_ on the target object
+4. The list of objects should reload without the deleted one 
+</details>
+
+<details>
+  <summary>☄️ Delete a Bucket</summary>
+  
+1. Navigate to the _Spaces_ section
+2. Select _Delete_ on the target Space/Bucket
+3. The list of buckets should reload without the deleted one 
+</details>
+
+<details>
+  <summary>👾 Generate a pre-signed URL</summary>
+  
+1. Navigate to the _Spaces_ section
+2. Select _Details_ on the target Space/Bucket
+3. Select _Magic Link_ on the target object
+4. A message should pop up, containing a pre-signed URL for that object (which is valid for 15 minutes) 
+</details>
+
+<details>
+  <summary>⏳ Set Expiration on Bucket</summary>
+
+1. Navigate to the _Spaces_ section
+2. Select _Make Temporary_ on the target Space/Bucket
+3. Select _Delete_ on the target object
+4. A message should pop up to indicate success 
+</details>
+
+<!-- CONTACT -->
+## Contact
+
+Joshua Görner - [jgoerner](https://www.linkedin.com/in/jgoerner/) - joshua.goerner[at]gmail.com
+
+
+<!-- ACKNOWLEDGEMENTS -->
+## Acknowledgements
+* [O. Drew](https://github.com/othneildrew/Best-README-Template) - nice GH Readme template
+* [Hatchful](https://hatchful.shopify.com/) - Easy Logo Generation

aws/s3/build.gradle

@@ -0,0 +1,41 @@
+plugins {
+    id 'org.springframework.boot' version '2.4.2'
+    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
+    id 'java'
+}
+
+group = 'io.jgoerner'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = '11'
+
+repositories {
+    mavenCentral()
+}
+
+ext {
+    // set('springCloudVersion', "Hoxton.SR9")
+    set('springCloudVersion', "Finchley.SR1")
+}
+
+
+dependencies {
+    annotationProcessor 'org.projectlombok:lombok'
+    developmentOnly 'org.springframework.boot:spring-boot-devtools'
+    implementation 'org.springframework.boot:spring-boot-starter-web'
+    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
+    implementation 'org.springframework.cloud:spring-cloud-starter-aws'
+    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+    implementation 'org.projectlombok:lombok:1.18.16'
+    runtimeOnly 'com.h2database:h2'
+    testImplementation 'org.springframework.boot:spring-boot-starter-test'
+}
+
+dependencyManagement {
+    imports {
+        mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
+    }
+}
+
+test {
+    useJUnitPlatform()
+}

aws/s3/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Mon Jan 04 22:38:53 CET 2021
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-all.zip
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME

aws/s3/gradlew

@@ -0,0 +1,185 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

aws/s3/gradlew.bat

@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

aws/s3/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 's3'

aws/s3/src/main/java/io/jgoerner/s3/S3Application.java

@@ -0,0 +1,38 @@
+package io.jgoerner.s3;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.autoconfigure.thymeleaf.ThymeleafProperties;
+import org.springframework.cloud.aws.autoconfigure.context.ContextInstanceDataAutoConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.thymeleaf.templateresolver.FileTemplateResolver;
+import org.thymeleaf.templateresolver.ITemplateResolver;
+
+@SpringBootApplication(exclude = ContextInstanceDataAutoConfiguration.class)
+public class S3Application {
+
+  private final ThymeleafProperties properties;
+
+  @Value("${spring.thymeleaf.templates_root:}")
+  private String templatesRoot;
+
+  public S3Application(ThymeleafProperties properties) {
+    this.properties = properties;
+  }
+
+  public static void main(String[] args) {
+    SpringApplication.run(S3Application.class, args);
+  }
+
+  @Bean
+  public ITemplateResolver defaultTemplateResolver() {
+    FileTemplateResolver resolver = new FileTemplateResolver();
+    resolver.setSuffix(properties.getSuffix());
+    resolver.setPrefix(templatesRoot);
+    resolver.setTemplateMode(properties.getMode());
+    resolver.setCacheable(properties.isCache());
+    return resolver;
+  }
+
+}

aws/s3/src/main/java/io/jgoerner/s3/adapter/in/RestApi.java

@@ -0,0 +1,128 @@
+package io.jgoerner.s3.adapter.in;
+
+import io.jgoerner.s3.application.port.in.object.*;
+import io.jgoerner.s3.application.port.in.space.*;
+import io.jgoerner.s3.domain.Object;
+import io.jgoerner.s3.domain.ObjectPartial;
+import io.jgoerner.s3.domain.Space;
+import io.jgoerner.s3.domain.SpacePartial;
+import lombok.SneakyThrows;
+import lombok.extern.log4j.Log4j2;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.multipart.MultipartFile;
+
+import java.net.URL;
+import java.util.List;
+import java.util.Optional;
+
+@RestController
+@RequestMapping("api")
+@Log4j2
+public class RestApi {
+
+  private final CreateSpace spaceCreator;
+  private final GetAllSpaces allSpaceGetter;
+  private final RemoveSpace spaceRemover;
+  private final GetAllObjects allObjectsInSpaceGetter;
+  private final UploadObject objectUploader;
+  private final UpdateObject objectUpdater;
+  private final RemoveObject objectDeleter;
+  private final ForceRemoveSpace forceSpaceRemover;
+  private final CreateLink linkCreator;
+  private final SetTTL ttlUpdater;
+  private final RemoveTTL ttlRemover;
+
+  public RestApi(
+      CreateSpace spaceCreator,
+      GetAllSpaces allSpaceGetter,
+      RemoveSpace spaceRemover,
+      GetAllObjects allObjectsInSpaceGetter,
+      UploadObject objectUploader,
+      UpdateObject objectUpdater,
+      RemoveObject objectDeleter,
+      ForceRemoveSpace forceSpaceRemover,
+      CreateLink linkCreator,
+      SetTTL ttlUpdater,
+      RemoveTTL ttlRemover) {
+    this.spaceCreator = spaceCreator;
+    this.allSpaceGetter = allSpaceGetter;
+    this.spaceRemover = spaceRemover;
+    this.allObjectsInSpaceGetter = allObjectsInSpaceGetter;
+    this.objectUploader = objectUploader;
+    this.objectUpdater = objectUpdater;
+    this.objectDeleter = objectDeleter;
+    this.forceSpaceRemover = forceSpaceRemover;
+    this.linkCreator = linkCreator;
+    this.ttlUpdater = ttlUpdater;
+    this.ttlRemover = ttlRemover;
+  }
+
+  @GetMapping("/space")
+  List<Space> getSpaces() {
+    return allSpaceGetter.getAll();
+  }
+
+  @PostMapping("/space/{space}")
+  Space postSpace(@PathVariable String space) {
+    return spaceCreator.create(space);
+  }
+
+  @DeleteMapping("/space/{space}")
+  void deleteSpace(@PathVariable String space, @RequestParam Optional<Boolean> force) {
+    log.info("Got the value " + force);
+    force.ifPresentOrElse(
+        value -> {
+          if (value) {
+            forceSpaceRemover.forceRemove(space);
+          } else {
+            spaceRemover.remove(space);
+          }
+        },
+        () -> spaceRemover.remove(space));
+  }
+
+  @GetMapping("/space/{space}/object")
+  List<Object> getObjectsInSpace(@PathVariable String space) {
+    return allObjectsInSpaceGetter.getAllObjects(space);
+  }
+
+  @SneakyThrows
+  @PostMapping("/space/{space}/object")
+  Object postObject(
+      @PathVariable String space,
+      @RequestParam("file") MultipartFile file,
+      @RequestParam(required = false, name = "name") String name) {
+    var key = name != null ? name : file.getOriginalFilename();
+    return objectUploader.upload(space, key, file.getInputStream());
+  }
+
+  @PatchMapping("/space/{space}/object/{key}")
+  Object patchObject(
+      @PathVariable String space, @PathVariable String key, @RequestBody ObjectPartial body) {
+    log.info("Got the partial " + body);
+    return objectUpdater.update(space, key, body);
+  }
+
+  @DeleteMapping("/space/{space}/object/{key}")
+  void deleteObject(@PathVariable String space, @PathVariable String key) {
+    objectDeleter.delete(space, key);
+  }
+
+  @PostMapping("/space/{space}/object/{key}/url")
+  URL createLink(
+      @PathVariable String space,
+      @PathVariable String key,
+      @RequestParam(required = false, name = "duration", defaultValue = "300") Long duration) {
+    return linkCreator.createLink(space, key, duration);
+  }
+
+  @PatchMapping("/space/{space}")
+  void patchSpace(@PathVariable String space, @RequestBody(required = false) SpacePartial body) {
+    log.info("got " + body);
+    if (body.getTtlInDays() > 1) {
+      ttlUpdater.setTTL(space, body.getTtlInDays());
+    } else {
+      ttlRemover.removeTTL(space);
+    }
+  }
+}

aws/s3/src/main/java/io/jgoerner/s3/adapter/in/View.java

@@ -0,0 +1,126 @@
+package io.jgoerner.s3.adapter.in;
+
+import io.jgoerner.s3.domain.ObjectPartial;
+import io.jgoerner.s3.domain.SpacePartial;
+import lombok.Data;
+import lombok.extern.log4j.Log4j2;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.multipart.MultipartFile;
+import org.springframework.web.servlet.mvc.support.RedirectAttributes;
+
+import java.util.Map;
+import java.util.Optional;
+
+@Log4j2
+@Controller()
+public class View {
+
+  private final RestApi api;
+
+  public View(RestApi api) {
+    this.api = api;
+  }
+
+  @GetMapping("space")
+  String space(Model model) {
+    var spaces = api.getSpaces();
+    model.addAttribute("spaces", spaces);
+    return "space-overview";
+  }
+
+  @GetMapping("space/{name}")
+  String spaceDetail(@PathVariable String name, Model model) {
+    model.addAllAttributes(Map.of("space", name, "objects", api.getObjectsInSpace(name)));
+    return "space-detail";
+  }
+
+  @GetMapping("space/{space}/make-public/{key}")
+  String makePublic(
+      @PathVariable String space, @PathVariable String key, RedirectAttributes redirectAttributes) {
+    api.patchObject(space, key, new ObjectPartial(true));
+    redirectAttributes.addFlashAttribute("success", "Made object public");
+    return "redirect:/space/" + space;
+  }
+
+  @GetMapping("space/{space}/make-private/{key}")
+  String makePrivate(
+      @PathVariable String space, @PathVariable String key, RedirectAttributes redirectAttributes) {
+    api.patchObject(space, key, new ObjectPartial(false));
+    redirectAttributes.addFlashAttribute("success", "Made object private");
+    return "redirect:/space/" + space;
+  }
+
+  @GetMapping("space/{space}/delete/{key}")
+  String deleteObject(@PathVariable String space, @PathVariable String key) {
+    api.deleteObject(space, key);
+    return "redirect:/space/" + space;
+  }
+
+  @GetMapping("/space/{space}/object-form")
+  String objectNew(@PathVariable String space, Model model) {
+    model.addAllAttributes(Map.of("space", space, "object", new ObjectForm()));
+    return "object-form";
+  }
+
+  @PostMapping("/space/{space}/object-form")
+  String postObject(
+      @PathVariable String space,
+      @RequestParam("file") MultipartFile file,
+      @ModelAttribute ObjectForm form,
+      RedirectAttributes redirectAttributes) {
+    api.postObject(space, file, form.getName());
+    redirectAttributes.addFlashAttribute("success", "Successfully uploaded " + form.getName());
+    return "redirect:/space/" + space;
+  }
+
+  @GetMapping("/space/{space}/magic/{key}")
+  String magicLink(
+      @PathVariable String space, @PathVariable String key, RedirectAttributes redirectAttributes) {
+    var link = api.createLink(space, key, 15L);
+    redirectAttributes.addFlashAttribute("warn", link);
+    return "redirect:/space/" + space;
+  }
+
+  @GetMapping("space-form")
+  String spaceNew(Model model) {
+    model.addAttribute("space", new SpaceForm());
+    return "space-form";
+  }
+
+  @PostMapping("space-form")
+  String newSpace(@ModelAttribute SpaceForm form, RedirectAttributes redirectAttributes) {
+    api.postSpace(form.getName());
+    redirectAttributes.addFlashAttribute("success", "Successfully created " + form.getName());
+    return "redirect:space";
+  }
+
+  @GetMapping("space/temporary/{name}")
+  String makeTemporary(@PathVariable String name) {
+    api.patchSpace(name, new SpacePartial(2));
+    return "redirect:/space";
+  }
+
+  @GetMapping("space/permanent/{name}")
+  String makePermanent(@PathVariable String name) {
+    api.patchSpace(name, new SpacePartial(-1));
+    return "redirect:/space";
+  }
+
+  @GetMapping("space/delete/{name}")
+  String delete(@PathVariable String name) {
+    api.deleteSpace(name, Optional.of(true));
+    return "redirect:/space";
+  }
+}
+
+@Data
+class SpaceForm {
+  String name;
+}
+
+@Data
+class ObjectForm {
+  String name;
+}

aws/s3/src/main/java/io/jgoerner/s3/adapter/out/h2/SpaceEntity.java

@@ -0,0 +1,20 @@
+package io.jgoerner.s3.adapter.out.h2;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+
+@Entity
+@NoArgsConstructor
+@AllArgsConstructor
+@Getter
+@Setter
+public class SpaceEntity {
+  @Id private String name;
+  private String bucket;
+  private Integer ttl;
+}

aws/s3/src/main/java/io/jgoerner/s3/adapter/out/h2/SpacePersistenceHandler.java

@@ -0,0 +1,69 @@
+package io.jgoerner.s3.adapter.out.h2;
+
+import io.jgoerner.s3.application.port.out.space.*;
+import io.jgoerner.s3.domain.Space;
+import lombok.extern.log4j.Log4j2;
+import org.springframework.stereotype.Component;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+@Component
+@Log4j2
+public class SpacePersistenceHandler
+    implements CheckSpaceExistence,
+        SaveSpace,
+        RetrieveAllSpaces,
+        ResolveSpaceName,
+        DeleteSpace,
+        RetrieveSpaceByName {
+
+  private final SpaceRepository spaceRepository;
+
+  public SpacePersistenceHandler(SpaceRepository spaceRepository) {
+    this.spaceRepository = spaceRepository;
+  }
+
+  @Override
+  public boolean doesExist(String name) {
+    return this.spaceRepository.findById(name).isPresent();
+  }
+
+  @Override
+  public Space save(Space name) {
+    this.spaceRepository.save(SpacePersistenceHandler.mapPojoToJpa(name));
+    return name;
+  }
+
+  @Override
+  public List<Space> findAll() {
+    return spaceRepository.findAll().stream()
+        .map(SpacePersistenceHandler::mapJpaToPojo)
+        .collect(Collectors.toList());
+  }
+
+  private static SpaceEntity mapPojoToJpa(Space space) {
+    return new SpaceEntity(space.getName(), space.getBucket(), space.getTtl());
+  }
+
+  private static Space mapJpaToPojo(SpaceEntity entity) {
+    return new Space(entity.getName(), entity.getBucket(), entity.getTtl());
+  }
+
+  @Override
+  public String resolve(String name) {
+    var bucket = spaceRepository.findById(name).get().getBucket();
+    log.info("Space " + name + " was resolved to " + bucket);
+    return bucket;
+  }
+
+  @Override
+  public void delete(String name) {
+    spaceRepository.deleteById(name);
+  }
+
+  @Override
+  public Space retrieveByName(String name) {
+    return mapJpaToPojo(spaceRepository.findById(name).orElseThrow());
+  }
+}

aws/s3/src/main/java/io/jgoerner/s3/adapter/out/h2/SpaceRepository.java

@@ -0,0 +1,7 @@
+package io.jgoerner.s3.adapter.out.h2;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface SpaceRepository extends JpaRepository<SpaceEntity, String> {}

aws/s3/src/main/java/io/jgoerner/s3/adapter/out/s3/S3Repository.java

@@ -0,0 +1,143 @@
+package io.jgoerner.s3.adapter.out.s3;
+
+import com.amazonaws.services.s3.AmazonS3Client;
+import com.amazonaws.services.s3.model.*;
+import com.amazonaws.services.s3.model.lifecycle.LifecycleFilter;
+import com.amazonaws.waiters.WaiterParameters;
+import io.jgoerner.s3.application.port.out.bucket.*;
+import io.jgoerner.s3.application.port.out.object.*;
+import io.jgoerner.s3.domain.Object;
+import lombok.extern.log4j.Log4j2;
+import org.springframework.stereotype.Repository;
+
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Date;
+import java.util.List;
+import java.util.stream.Collectors;
+
+@Repository
+@Log4j2
+public class S3Repository
+    implements CreateBucket,
+        DeleteBucket,
+        ListObjects,
+        SaveObject,
+        MakeObjectPublic,
+        MakeObjectPrivate,
+        DeleteObject,
+        CreatePresignedUrl,
+        SetVisibilityInObjectLifecycle,
+        RemoveVisibilityInObjectLifecycle {
+
+  private final AmazonS3Client s3Client;
+
+  public S3Repository(AmazonS3Client s3Client) {
+    this.s3Client = s3Client;
+  }
+
+  @Override
+  public void create(String bucket) {
+    // send bucket creation request
+    s3Client.createBucket(bucket);
+    log.info("Request to create " + bucket + " sent");
+
+    // assure that bucket is available
+    s3Client.waiters().bucketExists().run(new WaiterParameters<>(new HeadBucketRequest(bucket)));
+    log.info("Bucket " + bucket + " is ready");
+  }
+
+  @Override
+  public void delete(String bucket) {
+    // send deletion request
+    s3Client.deleteBucket(bucket);
+    log.info("Request to delete " + bucket + " sent");
+
+    // assure bucket is deleted
+    s3Client.waiters().bucketNotExists().run(new WaiterParameters(new HeadBucketRequest(bucket)));
+    log.info("Bucket " + bucket + " is deleted");
+  }
+
+  @Override
+  public List<Object> listObjectsInBucket(String bucket) {
+    var items =
+        s3Client.listObjectsV2(bucket).getObjectSummaries().stream()
+            .parallel()
+            .map(S3ObjectSummary::getKey)
+            .map(key -> mapS3ToObject(bucket, key))
+            .collect(Collectors.toList());
+
+    log.info("Found " + items.size() + " objects in the bucket " + bucket);
+    return items;
+  }
+
+  @Override
+  public Object safe(String bucket, String key, String name, InputStream payload) {
+    var metadata = new ObjectMetadata();
+    metadata.addUserMetadata("name", name);
+    s3Client.putObject(bucket, key, payload, metadata);
+    log.info("Sent the request");
+    return Object.builder().name(name).key(key).url(s3Client.getUrl(bucket, key)).build();
+  }
+
+  @Override
+  public void makePublic(String bucket, String key) {
+    s3Client.setObjectAcl(bucket, key, CannedAccessControlList.PublicRead);
+    log.info("Sent request to make object in bucket " + bucket + " with key " + key + " public");
+  }
+
+  @Override
+  public void makePrivate(String bucket, String key) {
+    s3Client.setObjectAcl(bucket, key, CannedAccessControlList.BucketOwnerFullControl);
+    log.info("Sent request to make object in bucket " + bucket + " with key " + key + " private");
+  }
+
+  @Override
+  public void delete(String bucket, String key) {
+    s3Client.deleteObject(bucket, key);
+    log.info("Sent request to delete file with key " + key + " in bucket " + bucket);
+  }
+
+  @Override
+  public URL createURL(String bucket, String key, Long duration) {
+    var date = new Date(new Date().getTime() + duration * 1000); // 1 s * 1000 ms/s
+    var url = s3Client.generatePresignedUrl(bucket, key, date);
+    log.info("Generated the signature " + url);
+    return url;
+  }
+
+  @Override
+  public void setVisibility(String bucket, Integer ttlInDays) {
+    s3Client.setBucketLifecycleConfiguration(
+        bucket,
+        new BucketLifecycleConfiguration()
+            .withRules(
+                new BucketLifecycleConfiguration.Rule()
+                    .withId("custom-expiration-id")
+                    .withFilter(new LifecycleFilter())
+                    .withStatus(BucketLifecycleConfiguration.ENABLED)
+                    .withExpirationInDays(ttlInDays)));
+  }
+
+  @Override
+  public void removeVisibility(String bucket) {
+    s3Client.deleteBucketLifecycleConfiguration(bucket);
+  }
+
+  private Object mapS3ToObject(String bucket, String key) {
+
+    return Object.builder()
+        .name(s3Client.getObjectMetadata(bucket, key).getUserMetaDataOf("name"))
+        .key(key)
+        .url(s3Client.getUrl(bucket, key))
+        .isPublic(
+            s3Client.getObjectAcl(bucket, key).getGrantsAsList().stream()
+                .anyMatch(grant -> grant.equals(S3Repository.publicObjectReadGrant())))
+        .build();
+  }
+
+  private static Grant publicObjectReadGrant() {
+    return new Grant(
+        GroupGrantee.parseGroupGrantee(GroupGrantee.AllUsers.getIdentifier()), Permission.Read);
+  }
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/object/CreateLink.java

@@ -0,0 +1,7 @@
+package io.jgoerner.s3.application.port.in.object;
+
+import java.net.URL;
+
+public interface CreateLink {
+  URL createLink(String space, String key, Long duration);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/object/GetAllObjects.java

@@ -0,0 +1,9 @@
+package io.jgoerner.s3.application.port.in.object;
+
+import io.jgoerner.s3.domain.Object;
+
+import java.util.List;
+
+public interface GetAllObjects {
+  List<Object> getAllObjects(String space);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/object/RemoveObject.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.in.object;
+
+public interface RemoveObject {
+    void delete(String space, String key);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/object/UpdateObject.java

@@ -0,0 +1,8 @@
+package io.jgoerner.s3.application.port.in.object;
+
+import io.jgoerner.s3.domain.ObjectPartial;
+import io.jgoerner.s3.domain.Object;
+
+public interface UpdateObject {
+  Object update(String space, String key, ObjectPartial updates);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/object/UploadObject.java

@@ -0,0 +1,9 @@
+package io.jgoerner.s3.application.port.in.object;
+
+import io.jgoerner.s3.domain.Object;
+
+import java.io.InputStream;
+
+public interface UploadObject {
+  Object upload(String space, String name, InputStream payload);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/space/CreateSpace.java

@@ -0,0 +1,7 @@
+package io.jgoerner.s3.application.port.in.space;
+
+import io.jgoerner.s3.domain.Space;
+
+public interface CreateSpace {
+  Space create(String name);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/space/ForceRemoveSpace.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.in.space;
+
+public interface ForceRemoveSpace {
+    void forceRemove(String space);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/space/GetAllSpaces.java

@@ -0,0 +1,9 @@
+package io.jgoerner.s3.application.port.in.space;
+
+import io.jgoerner.s3.domain.Space;
+
+import java.util.List;
+
+public interface GetAllSpaces {
+  List<Space> getAll();
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/space/RemoveSpace.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.in.space;
+
+public interface RemoveSpace {
+  void remove(String space);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/space/RemoveTTL.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.in.space;
+
+public interface RemoveTTL {
+  void removeTTL(String space);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/in/space/SetTTL.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.in.space;
+
+public interface SetTTL {
+  void setTTL(String space, Integer ttlInDays);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/bucket/CreateBucket.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.bucket;
+
+public interface CreateBucket {
+  void create(String bucket);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/bucket/DeleteBucket.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.bucket;
+
+public interface DeleteBucket {
+  void delete(String bucket);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/bucket/ListObjects.java

@@ -0,0 +1,9 @@
+package io.jgoerner.s3.application.port.out.bucket;
+
+import io.jgoerner.s3.domain.Object;
+
+import java.util.List;
+
+public interface ListObjects {
+  List<Object> listObjectsInBucket(String bucket);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/bucket/RemoveVisibilityInObjectLifecycle.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.bucket;
+
+public interface RemoveVisibilityInObjectLifecycle {
+  void removeVisibility(String bucket);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/bucket/SetVisibilityInObjectLifecycle.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.bucket;
+
+public interface SetVisibilityInObjectLifecycle {
+  void setVisibility(String bucket, Integer ttlInDays);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/object/CreatePresignedUrl.java

@@ -0,0 +1,7 @@
+package io.jgoerner.s3.application.port.out.object;
+
+import java.net.URL;
+
+public interface CreatePresignedUrl {
+  URL createURL(String bucket, String key, Long duration);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/object/DeleteObject.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.object;
+
+public interface DeleteObject {
+    void delete(String bucket, String key);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/object/MakeObjectPrivate.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.object;
+
+public interface MakeObjectPrivate {
+  void makePrivate(String bucket, String key);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/object/MakeObjectPublic.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.object;
+
+public interface MakeObjectPublic {
+  void makePublic(String bucket, String key);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/object/SaveObject.java

@@ -0,0 +1,9 @@
+package io.jgoerner.s3.application.port.out.object;
+
+import io.jgoerner.s3.domain.Object;
+
+import java.io.InputStream;
+
+public interface SaveObject {
+  Object safe(String bucket, String key, String name, InputStream payload);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/space/CheckSpaceExistence.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.space;
+
+public interface CheckSpaceExistence {
+  boolean doesExist(String name);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/space/DeleteSpace.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.space;
+
+public interface DeleteSpace {
+  void delete(String name);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/space/ResolveSpaceName.java

@@ -0,0 +1,5 @@
+package io.jgoerner.s3.application.port.out.space;
+
+public interface ResolveSpaceName {
+  String resolve(String name);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/space/RetrieveAllSpaces.java

@@ -0,0 +1,9 @@
+package io.jgoerner.s3.application.port.out.space;
+
+import io.jgoerner.s3.domain.Space;
+
+import java.util.List;
+
+public interface RetrieveAllSpaces {
+  List<Space> findAll();
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/space/RetrieveSpaceByName.java

@@ -0,0 +1,7 @@
+package io.jgoerner.s3.application.port.out.space;
+
+import io.jgoerner.s3.domain.Space;
+
+public interface RetrieveSpaceByName {
+  Space retrieveByName(String name);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/port/out/space/SaveSpace.java

@@ -0,0 +1,7 @@
+package io.jgoerner.s3.application.port.out.space;
+
+import io.jgoerner.s3.domain.Space;
+
+public interface SaveSpace {
+  Space save(Space name);
+}

aws/s3/src/main/java/io/jgoerner/s3/application/service/ObjectService.java

@@ -0,0 +1,105 @@
+package io.jgoerner.s3.application.service;
+
+import io.jgoerner.s3.application.port.in.object.CreateLink;
+import io.jgoerner.s3.application.port.in.object.RemoveObject;
+import io.jgoerner.s3.application.port.in.object.UpdateObject;
+import io.jgoerner.s3.application.port.in.object.UploadObject;
+import io.jgoerner.s3.application.port.out.object.*;
+import io.jgoerner.s3.application.port.out.space.ResolveSpaceName;
+import io.jgoerner.s3.domain.Object;
+import io.jgoerner.s3.domain.ObjectPartial;
+import lombok.extern.log4j.Log4j2;
+import org.springframework.stereotype.Service;
+
+import java.io.InputStream;
+import java.net.URL;
+import java.util.UUID;
+
+@Service
+@Log4j2
+public class ObjectService implements UploadObject, UpdateObject, RemoveObject, CreateLink {
+
+  private final ResolveSpaceName bucketNameResolver;
+  private final SaveObject objectSaver;
+  private final MakeObjectPublic objectPublicMaker;
+  private final MakeObjectPrivate objectPrivateMaker;
+  private final DeleteObject objectDeleter;
+  private final CreatePresignedUrl presignedUrlCreator;
+
+  public ObjectService(
+      ResolveSpaceName bucketNameResolver,
+      SaveObject objectSaver,
+      MakeObjectPublic objectPublicMaker,
+      MakeObjectPrivate objectPrivateMaker,
+      DeleteObject objectDeleter,
+      CreatePresignedUrl presignedUrlCreator) {
+    this.bucketNameResolver = bucketNameResolver;
+    this.objectSaver = objectSaver;
+    this.objectPublicMaker = objectPublicMaker;
+    this.objectPrivateMaker = objectPrivateMaker;
+    this.objectDeleter = objectDeleter;
+    this.presignedUrlCreator = presignedUrlCreator;
+  }
+
+  @Override
+  public Object upload(String space, String name, InputStream payload) {
+    // check if bucket exists
+    var bucket = bucketNameResolver.resolve(space);
+
+    // generate a id & store in lookup table
+    var key = UUID.randomUUID().toString();
+
+    // save
+    log.info(
+        "Going to upload the file into to "
+            + bucket
+            + "/"
+            + key
+            + " with metadata name of "
+            + name);
+
+    return objectSaver.safe(bucket, key, name, payload);
+  }
+
+  @Override
+  public Object update(String space, String key, ObjectPartial updates) {
+    var bucket = bucketNameResolver.resolve(space);
+
+    if (updates.getIsPublic() != null) {
+      if (updates.getIsPublic()) {
+        log.info("going to open up to public");
+        objectPublicMaker.makePublic(bucket, key);
+      } else {
+        log.info("going to remove public access");
+        objectPrivateMaker.makePrivate(bucket, key);
+      }
+    }
+
+    return null;
+  }
+
+  @Override
+  public void delete(String space, String key) {
+    var bucket = bucketNameResolver.resolve(space);
+
+    log.info("Going to delete the file with the key " + key + " in the bucket " + bucket);
+
+    objectDeleter.delete(bucket, key);
+  }
+
+  @Override
+  public URL createLink(String space, String key, Long duration) {
+    var bucket = bucketNameResolver.resolve(space);
+
+    log.info(
+        "Going to generate a link for the file "
+            + key
+            + " in bucket "
+            + bucket
+            + " with visibility duration of "
+            + duration
+            + " seconds");
+
+    return presignedUrlCreator.createURL(bucket, key, duration);
+  }
+}

aws/s3/src/main/java/io/jgoerner/s3/application/service/SpaceService.java

@@ -0,0 +1,155 @@
+package io.jgoerner.s3.application.service;
+
+import io.jgoerner.s3.application.port.in.object.GetAllObjects;
+import io.jgoerner.s3.application.port.in.object.RemoveObject;
+import io.jgoerner.s3.application.port.in.space.*;
+import io.jgoerner.s3.application.port.out.bucket.*;
+import io.jgoerner.s3.application.port.out.object.DeleteObject;
+import io.jgoerner.s3.application.port.out.space.*;
+import io.jgoerner.s3.domain.Object;
+import io.jgoerner.s3.domain.Space;
+import lombok.extern.log4j.Log4j2;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.UUID;
+
+@Service
+@Log4j2
+public class SpaceService
+    implements CreateSpace,
+        GetAllSpaces,
+        GetAllObjects,
+        RemoveSpace,
+        ForceRemoveSpace,
+        SetTTL,
+        RemoveTTL {
+
+  private final CheckSpaceExistence spaceExistenceChecker;
+  private final SaveSpace spaceSaver;
+  private final RetrieveAllSpaces allSpaceRetriever;
+  private final CreateBucket bucketCreator;
+  private final ResolveSpaceName bucketNameResolver;
+  private final DeleteBucket bucketDeleter;
+  private final DeleteSpace spaceDeleter;
+  private final ListObjects objectLister;
+  private final DeleteObject objectDeleter;
+  private final SetVisibilityInObjectLifecycle objectLifecycleVisibilitySetter;
+  private final RemoveVisibilityInObjectLifecycle objectLifecycleVisibilityRemover;
+  private final RetrieveSpaceByName spaceByNameRetriever;
+
+  public SpaceService(
+      CheckSpaceExistence spaceExistenceChecker,
+      SaveSpace spaceSaver,
+      RetrieveAllSpaces allSpaceRetriever,
+      CreateBucket bucketCreator,
+      ResolveSpaceName bucketNameResolver,
+      DeleteBucket bucketDeleter,
+      DeleteSpace spaceDeleter,
+      ListObjects objectLister,
+      RemoveObject objectRemover,
+      DeleteObject objectDeleter,
+      SetVisibilityInObjectLifecycle objectLifecycleVisibilitySetter,
+      RemoveVisibilityInObjectLifecycle objectLifecycleVisibilityRemover,
+      RetrieveSpaceByName spaceByNameRetriever) {
+    this.spaceExistenceChecker = spaceExistenceChecker;
+    this.spaceSaver = spaceSaver;
+    this.allSpaceRetriever = allSpaceRetriever;
+    this.bucketNameResolver = bucketNameResolver;
+    this.bucketCreator = bucketCreator;
+    this.bucketDeleter = bucketDeleter;
+    this.spaceDeleter = spaceDeleter;
+    this.objectLister = objectLister;
+    this.objectDeleter = objectDeleter;
+    this.objectLifecycleVisibilitySetter = objectLifecycleVisibilitySetter;
+    this.objectLifecycleVisibilityRemover = objectLifecycleVisibilityRemover;
+    this.spaceByNameRetriever = spaceByNameRetriever;
+  }
+
+  @Override
+  public Space create(String name) {
+    // check if bucket exists
+    if (spaceExistenceChecker.doesExist(name)) {
+      log.info("Space " + name + " does already exist");
+      return null;
+    }
+
+    // create
+    Space space = new Space(name, "spring-boot-s3-tutorial-" + UUID.randomUUID().toString(), null);
+    log.info("Mapped space to bucket " + space);
+    bucketCreator.create(space.getBucket());
+
+    // create bucket meta
+    return this.spaceSaver.save(space);
+  }
+
+  @Override
+  public List<Space> getAll() {
+    var buckets = allSpaceRetriever.findAll();
+    log.info("Found " + buckets.size() + " buckets");
+    return buckets;
+  }
+
+  @Override
+  public List<Object> getAllObjects(String space) {
+    // get bucket from H2
+    var bucket = bucketNameResolver.resolve(space);
+
+    // return all files in bucket
+    return objectLister.listObjectsInBucket(bucket);
+  }
+
+  @Override
+  public void remove(String space) {
+    // get bucket from H2
+    var bucket = bucketNameResolver.resolve(space);
+
+    // delete from S3
+    bucketDeleter.delete(bucket);
+
+    // delete from H2
+    spaceDeleter.delete(space);
+  }
+
+  @Override
+  public void forceRemove(String space) {
+    // get bucket from H2
+    var bucket = bucketNameResolver.resolve(space);
+
+    // empty bucket
+    getAllObjects(space).stream()
+        .peek(log::info)
+        .forEach(object -> objectDeleter.delete(bucket, object.getKey()));
+
+    // get rid of bucket
+    remove(space);
+  }
+
+  @Override
+  public void setTTL(String space, Integer ttlInDays) {
+    var bucket = bucketNameResolver.resolve(space);
+    log.info("Going to adjust the TTL for the bucket " + bucket + " to " + ttlInDays + " day(s)");
+
+    // S3
+    objectLifecycleVisibilitySetter.setVisibility(bucket, ttlInDays);
+
+    // H2
+    var spaceEntity = spaceByNameRetriever.retrieveByName(space);
+    spaceEntity.setTtl(ttlInDays);
+    spaceSaver.save(spaceEntity);
+  }
+
+  @Override
+  public void removeTTL(String space) {
+    var bucket = bucketNameResolver.resolve(space);
+    log.info("Going to remove TTL policy for bucket " + bucket);
+
+    // S3
+    objectLifecycleVisibilityRemover.removeVisibility(bucket);
+
+    // H2
+    var spaceEntity = spaceByNameRetriever.retrieveByName(space);
+    spaceEntity.setTtl(null);
+    spaceSaver.save(spaceEntity);
+  }
+}

aws/s3/src/main/java/io/jgoerner/s3/domain/Object.java

@@ -0,0 +1,15 @@
+package io.jgoerner.s3.domain;
+
+import lombok.Builder;
+import lombok.Value;
+
+import java.net.URL;
+
+@Value
+@Builder
+public class Object {
+  String name;
+  String key;
+  URL url;
+  @Builder.Default boolean isPublic = false;
+}

aws/s3/src/main/java/io/jgoerner/s3/domain/ObjectPartial.java

@@ -0,0 +1,12 @@
+package io.jgoerner.s3.domain;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Data
+public class ObjectPartial {
+  Boolean isPublic;
+}

aws/s3/src/main/java/io/jgoerner/s3/domain/Space.java

@@ -0,0 +1,12 @@
+package io.jgoerner.s3.domain;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@AllArgsConstructor
+@Data
+public class Space {
+  String name;
+  String bucket;
+  Integer ttl;
+}

aws/s3/src/main/java/io/jgoerner/s3/domain/SpacePartial.java

@@ -0,0 +1,12 @@
+package io.jgoerner.s3.domain;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Data
+public class SpacePartial {
+  Integer ttlInDays;
+}

aws/s3/src/main/resources/application.yaml

@@ -0,0 +1,36 @@
+spring:
+  datasource:
+    url: jdbc:h2:./data/metadb
+    username: admin
+  h2:
+    console:
+      enabled: true
+      path: /h2
+  jpa:
+    hibernate:
+      ddl-auto: update
+  # https://stackoverflow.com/questions/40057057/spring-boot-and-thymeleaf-hot-swap-templates-and-resources-once-again
+  thymeleaf:
+    cache: false
+    templates_root: src/main/resources/templates/
+  servlet:
+    multipart:
+      max-file-size: 15MB
+      max-request-size: 15MB
+
+cloud:
+  aws:
+    region:
+      static: eu-central-1
+    stack:
+      auto: false
+    credentials:
+      profile-name: dev
+
+# https://docs.spring.io/spring-cloud-aws/docs/2.2.3.RELEASE/reference/html/#amazon-sdk-configuration
+logging:
+  level:
+    com:
+      amazonaws:
+        util:
+          EC2MetadataUtils: error

aws/s3/src/main/resources/templates/fragments/head.html

@@ -0,0 +1,7 @@
+<head th:fragment="head" xmlns:th="http://www.w3.org/1999/xhtml">
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <title>File Share</title>
+    <link rel="stylesheet" th:href="@{/css/bulma.min.css}">
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.2/css/all.min.css">
+</head>

aws/s3/src/main/resources/templates/fragments/navbar.html

@@ -0,0 +1,43 @@
+<nav class="navbar" th:fragment="navbar" xmlns:th="http://www.w3.org/1999/xhtml">
+    <div class=" container">
+
+        <div class="navbar-brand">
+            <a class="navbar-item" href="/">
+                       <span class="icon-text">
+                           <span class="icon">
+                               <i class="fas fa-home"></i>
+                           </span>
+                           <span>Home</span>
+                       </span>
+            </a>
+            <a class="navbar-item" th:href="@{~/space}">
+                       <span class="icon-text">
+                           <span class="icon">
+                               <i class="fas fa-folder-open"></i>
+                           </span>
+                           <span>Spaces</span>
+                       </span>
+            </a>
+        </div>
+        <div class="navbar-menu">
+            <div class="navbar-end">
+                <a class="navbar-item" href="h2" target="_blank">
+                       <span class="icon-text">
+                           <span class="icon">
+                               <i class="fas fa-database"></i>
+                           </span>
+                           <span>DB</span>
+                       </span>
+                </a>
+                <span class="navbar-item">
+              <a class="button is-primary" href="https://github.com/jgoerner" target="_blank">
+                <span class="icon">
+                  <i class="fab fa-github"></i>
+                </span>
+                <span>GitHub</span>
+              </a>
+            </span>
+            </div>
+        </div>
+    </div>
+</nav>

aws/s3/src/main/resources/templates/fragments/notification.html

@@ -0,0 +1,23 @@
+<script th:inline="javascript" th:fragment="script" xmlns:th="http://www.w3.org/1999/xhtml">
+    document.addEventListener('DOMContentLoaded', () => {
+        (document.querySelectorAll('.notification .delete') || []).forEach(($delete) => {
+            var $notification = $delete.parentNode;
+
+            $delete.addEventListener('click', () => {
+                $notification.parentNode.removeChild($notification);
+            });
+        });
+    });
+</script>
+
+<div th:fragment="notification" xmlns:th="http://www.w3.org/1999/xhtml">
+
+    <div class="notification" th:if="${success}">
+        <button class="delete"></button>
+        <p class="has-text-grey-light" th:text="${success}"/>
+    </div>
+    <div class="notification is-warning is-light" th:if="${warn}">
+        <button class="delete"></button>
+        <p th:text="${warn}"/>
+    </div>
+</div>

aws/s3/src/main/resources/templates/index.html

@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml"
+      xmlns:th="http://www.thymeleaf.org">
+<head th:replace="fragments/head :: head"/>
+<body>
+
+<div th:replace="fragments/navbar :: navbar"/>
+
+<section class="hero is-primary is-fullheight-with-navbar is-bold">
+    <div class="hero-body">
+        <div class="container has-text-centered">
+            <h1 class="title">
+                Private File Share
+            </h1>
+            <h2 class="subtitle">
+                powered by Spring Boot & Simple Storage Service (S3)
+            </h2>
+
+        </div>
+    </div>
+</section>
+
+</body>
+</html>

aws/s3/src/main/resources/templates/object-form.html

@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml"
+      xmlns:th="http://www.thymeleaf.org">
+<head th:replace="fragments/head :: head"/>
+<body>
+
+<div th:replace="fragments/navbar :: navbar"/>
+
+<section class="hero is-fullheight-with-navbar is-primary is-bold">
+
+    <section class="hero-body columns is-centered  m-0">
+        <div class="column is-half  ">
+            <form action="#" th:action="@{/space/__${space}__/object-form}" th:object="${object}" method="post"
+                  enctype="multipart/form-data">
+                <div class="field">
+                    <div class="control has-icons-left">
+                        <input class="input is-medium" type="text" th:field="*{name}" placeholder="Name of your File">
+                        <span class="icon is-small is-left">
+                            <i class="fas fa-heading"></i>
+                        </span>
+                    </div>
+                    <p class="help">Human readable name of the file</p>
+                </div>
+
+                <div class="field">
+                    <div class="control">
+                        <input type="file" name="file"/>
+                    </div>
+                    <p class="help">Human readable name of the file</p>
+                </div>
+
+                <div class="field is-grouped is-grouped-centered">
+                    <p class="control">
+                        <button class="button is-primary is-outlined is-inverted" type="submit">
+                            Submit
+                        </button>
+                    </p>
+                    <p class="control">
+                        <a class="button is-primary is-outlined is-inverted" href="#">
+                            Cancel
+                        </a>
+                    </p>
+                </div>
+            </form>
+        </div>
+    </section>
+</section>
+</body>
+</html>

aws/s3/src/main/resources/templates/space-detail.html

@@ -0,0 +1,81 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml"
+      xmlns:th="http://www.thymeleaf.org">
+<head th:replace="fragments/head :: head"/>
+<body>
+
+<div th:replace="fragments/navbar :: navbar"/>
+
+<section class="hero is-fullheight-with-navbar is-primary is-bold">
+
+    <section class="hero-body columns is-centered  m-0">
+        <div class="column is-half has-text-centered">
+            <div th:replace="fragments/notification :: notification"/>
+            <div th:each="object: ${objects}" class="card m-4">
+                <div class="card-content">
+                    <div class="media">
+                        <div class="media-content">
+                            <p class="title is-4 has-text-dark" th:text="${object.name}"/>
+                            <p class="subtitle is-6 has-text-grey-light mb-1" th:text="${object.key}"/>
+                            <p th:if="${object.isPublic}" class="subtitle is-6 has-text-grey-light">
+                                Publicly accessible
+                            </p>
+                            <p th:unless="${object.isPublic}" class="subtitle is-6 has-text-grey-light">Private</p>
+                        </div>
+                    </div>
+                </div>
+                <div class="card-footer">
+                    <a th:href="${object.url}" target="_blank"
+                       class="card-footer-item has-text-info">
+                        <span class="icon is-small pr-3">
+                            <i class="fas fa-download"></i>
+                        </span>
+                        <span>Download</span>
+                    </a>
+                    <a th:if="${object.isPublic}" th:href="@{~/space/__${space}__/make-private/__${object.key}__}"
+                       class="card-footer-item has-text-info">
+                    <span class="icon is-small pr-3">
+                            <i class="fas fa-eye-slash"></i>
+                        </span>
+                        <span>Make Private</span>
+                    </a>
+                    <a th:unless="${object.isPublic}" th:href="@{~/space/__${space}__/make-public/__${object.key}__}"
+                       class="card-footer-item has-text-info">
+                    <span class="icon is-small pr-3">
+                            <i class="fas fa-eye"></i>
+                        </span>
+                        <span>Make Public</span>
+                    </a>
+                    <a th:href="@{~/space/__${space}__/magic/__${object.key}__}"
+                       class="card-footer-item has-text-info">
+                        <span class="icon is-small pr-3">
+                            <i class="fas fa-magic"></i>
+                        </span>
+                        <span>Magic Link</span>
+                    </a>
+                    <a th:href="@{~/space/__${space}__/delete/__${object.key}__}"
+                       class="card-footer-item has-text-danger">
+                        <span class="icon is-small pr-3">
+                            <i class="fas fa-trash-alt"></i>
+                        </span>
+                        <span>Delete</span>
+                    </a>
+
+                </div>
+            </div>
+            <button class="button is-medium is-primary is-inverted is-outlined ">
+                <a th:href="@{~/space/__${space}__/object-form}">
+                <span class="icon is-small">
+                   <i class="fas fa-upload"></i>
+                </span>
+                    <span>Upload File</span>
+                </a>
+            </button>
+        </div>
+    </section>
+</section>
+
+<script th:replace="fragments/notification :: script"/>
+
+</body>
+</html>

aws/s3/src/main/resources/templates/space-form.html

@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml"
+      xmlns:th="http://www.thymeleaf.org">
+<head th:replace="fragments/head :: head"/>
+<body>
+
+<div th:replace="fragments/navbar :: navbar"/>
+
+<section class="hero is-fullheight-with-navbar is-primary is-bold">
+
+    <section class="hero-body columns is-centered  m-0">
+        <div class="column is-half  ">
+            <form action="#" th:action="@{/space-form}" th:object="${space}" method="post">
+                <div class="field">
+                    <div class="control has-icons-left">
+                        <input class="input is-medium" type="text" th:field="*{name}" placeholder="Name of your space">
+                        <span class="icon is-small is-left">
+                            <i class="fas fa-heading"></i>
+                        </span>
+                    </div>
+                    <p class="help">Human readable name of the bucket</p>
+
+                </div>
+                <div class="field is-grouped is-grouped-centered">
+                    <p class="control">
+                        <button class="button is-primary is-outlined is-inverted" type="submit">
+                            Submit
+                        </button>
+                    </p>
+                    <p class="control">
+                        <a class="button is-primary is-outlined is-inverted" href="space">
+                            Cancel
+                        </a>
+                    </p>
+                </div>
+            </form>
+        </div>
+    </section>
+</section>
+</body>
+</html>

aws/s3/src/main/resources/templates/space-overview.html

@@ -0,0 +1,73 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml"
+      xmlns:th="http://www.thymeleaf.org">
+<head th:replace="fragments/head :: head"/>
+
+<body>
+<div th:replace="fragments/navbar :: navbar"/>
+
+<section class="hero is-fullheight-with-navbar is-primary is-bold">
+
+    <section class="hero-body columns is-centered  m-0">
+        <div class="column is-half has-text-centered">
+            <div th:replace="fragments/notification :: notification"/>
+            <div th:each="space: ${spaces}" class="card m-4">
+                <div class="card-content">
+                    <div class="media">
+                        <div class="media-content">
+                            <p class="title is-4 has-text-dark" th:text="${space.name}"/>
+                            <p class="subtitle is-6 has-text-grey-light mb-1" th:text="${space.bucket}"/>
+                            <p th:if=${space.ttl} class="subtitle is-6 has-text-grey-light"
+                               th:text="${'Only storing files for ' + space.ttl + ' days'}"/>
+                            <p th:unless=${space.ttl} class="subtitle is-6 has-text-grey-light"
+                            >Permanent Storage</p>
+                        </div>
+                    </div>
+                </div>
+                <div class="card-footer">
+                    <a th:href="@{space/__${space.name}__}"
+                       class="card-footer-item has-text-info">
+                        <span class="icon is-small pr-3">
+                            <i class="fas fa-info"></i>
+                        </span>
+                        <span>Details</span>
+                    </a>
+                    <a th:unless="${space.ttl}" th:href="@{space/temporary/__${space.name}__}"
+                       class="card-footer-item has-text-info">
+                        <span class="icon is-small pr-3">
+                            <i class="fas fa-hourglass-half"></i>
+                        </span>
+                        <span>Make Temporary</span>
+                    </a>
+                    <a th:if="${space.ttl}" th:href="@{space/permanent/__${space.name}__}"
+                       class="card-footer-item has-text-info">
+                        <span class="icon is-small pr-3">
+                            <i class="fas fa-infinity"></i>
+                        </span>
+                        <span>Make Permanent</span>
+                    </a>
+                    <a th:href="@{space/delete/__${space.name}__}"
+                       class="card-footer-item has-text-danger">
+                        <span class="icon is-small pr-3">
+                            <i class="fas fa-trash-alt"></i>
+                        </span>
+                        <span>Delete</span>
+                    </a>
+                </div>
+            </div>
+            <button class="button is-medium is-primary is-inverted is-outlined ">
+                <a href="space-form">
+                <span class="icon is-small">
+                   <i class="fas fa-plus-square"></i>
+                </span>
+                    <span>New Space</span>
+                </a>
+            </button>
+        </div>
+    </section>
+</section>
+
+<script th:replace="fragments/notification :: script"/>
+
+</body>
+</html>

aws/s3/src/test/java/io/jgoerner/s3/S3ApplicationTests.java

@@ -0,0 +1,13 @@
+package io.jgoerner.s3;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class S3ApplicationTests {
+
+	@Test
+	void contextLoads() {
+	}
+
+}

build-all.sh

@@ -86,6 +86,16 @@ if [[ "$MODULE" == "module5" ]]
 then
   # ADD NEW MODULES HERE
   # (add new modules above the rest so you get quicker feedback if it fails)
+  build_maven_module "core-java/service-provider-interface"
+  build_gradle_module "spring-boot/hazelcast/hazelcast-embedded-cache"
+  build_gradle_module "spring-boot/hazelcast/hazelcast-client-server"
+  build_maven_module "core-java/heapdump"
+  build_gradle_module "aws/s3"
+  build_maven_module "graphql"
+  build_gradle_module "spring-boot/exception-handling"
+  build_maven_module "spring-boot/spring-boot-elasticsearch"
+  build_gradle_module "spring-boot/spring-boot-mocking-modules"
+  build_gradle_module "spring-boot/specification"
   build_gradle_module "spring-boot/hibernate-search"
   build_maven_module "core-java/streams/fileswithstreams"
   build_maven_module "spring-boot/spring-boot-health-check"
@@ -97,8 +107,6 @@ then
   build_gradle_module "spring-boot/bean-lifecycle"
   build_gradle_module "spring-boot/request-response/client"
   build_gradle_module "spring-boot/request-response/server"
-  build_gradle_module "spring-boot/hazelcast/hazelcast-embedded-cache"
-  build_gradle_module "spring-boot/hazelcast/hazelcast-client-server"
 
   echo ""
   echo "+++"
@@ -109,6 +117,7 @@ fi
 
 if [[ "$MODULE" == "module1" ]]
 then
+  build_maven_module "spring-boot/spring-boot-cookie-demo"
   build_maven_module "spring-boot/spring-boot-kafka"
   build_gradle_module "spring-boot/spring-boot-springdoc"
   build_maven_module "spring-boot/dependency-injection"
@@ -135,6 +144,7 @@ then
   build_maven_module "resilience4j/ratelimiter"
   build_maven_module "resilience4j/timelimiter"
   build_maven_module "resilience4j/bulkhead"
+  build_maven_module "resilience4j/circuitbreaker"
   build_gradle_module "spring-data/spring-data-jdbc-converter"
   build_gradle_module "reactive"
   build_gradle_module "junit/assumptions"
@@ -187,4 +197,4 @@ then
   echo "+++"
   echo "+++ MODULE 4 SUCCESSFUL"
   echo "+++"
-fi
+fi

core-java/heapdump/.mvn/wrapper/MavenWrapperDownloader.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2007-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import java.net.*;
+import java.io.*;
+import java.nio.channels.*;
+import java.util.Properties;
+
+public class MavenWrapperDownloader {
+
+    private static final String WRAPPER_VERSION = "0.5.6";
+    /**
+     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
+     */
+    private static final String DEFAULT_DOWNLOAD_URL = "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/"
+        + WRAPPER_VERSION + "/maven-wrapper-" + WRAPPER_VERSION + ".jar";
+
+    /**
+     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
+     * use instead of the default one.
+     */
+    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
+            ".mvn/wrapper/maven-wrapper.properties";
+
+    /**
+     * Path where the maven-wrapper.jar will be saved to.
+     */
+    private static final String MAVEN_WRAPPER_JAR_PATH =
+            ".mvn/wrapper/maven-wrapper.jar";
+
+    /**
+     * Name of the property which should be used to override the default download url for the wrapper.
+     */
+    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
+
+    public static void main(String args[]) {
+        System.out.println("- Downloader started");
+        File baseDirectory = new File(args[0]);
+        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
+
+        // If the maven-wrapper.properties exists, read it and check if it contains a custom
+        // wrapperUrl parameter.
+        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
+        String url = DEFAULT_DOWNLOAD_URL;
+        if(mavenWrapperPropertyFile.exists()) {
+            FileInputStream mavenWrapperPropertyFileInputStream = null;
+            try {
+                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
+                Properties mavenWrapperProperties = new Properties();
+                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
+                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
+            } catch (IOException e) {
+                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
+            } finally {
+                try {
+                    if(mavenWrapperPropertyFileInputStream != null) {
+                        mavenWrapperPropertyFileInputStream.close();
+                    }
+                } catch (IOException e) {
+                    // Ignore ...
+                }
+            }
+        }
+        System.out.println("- Downloading from: " + url);
+
+        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
+        if(!outputFile.getParentFile().exists()) {
+            if(!outputFile.getParentFile().mkdirs()) {
+                System.out.println(
+                        "- ERROR creating output directory '" + outputFile.getParentFile().getAbsolutePath() + "'");
+            }
+        }
+        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
+        try {
+            downloadFileFromURL(url, outputFile);
+            System.out.println("Done");
+            System.exit(0);
+        } catch (Throwable e) {
+            System.out.println("- Error downloading");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
+        if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
+            String username = System.getenv("MVNW_USERNAME");
+            char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
+            Authenticator.setDefault(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication(username, password);
+                }
+            });
+        }
+        URL website = new URL(urlString);
+        ReadableByteChannel rbc;
+        rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(destination);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        fos.close();
+        rbc.close();
+    }
+
+}

core-java/heapdump/.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,2 @@
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar

core-java/heapdump/README.md

@@ -0,0 +1,3 @@
+# Related Blog Posts
+
+* [How to do heap dump analysis](https://reflectoring.io/create-analyze-heapdump/)

core-java/heapdump/mvnw

@@ -0,0 +1,310 @@
+#!/bin/sh
+# ----------------------------------------------------------------------------
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+# ----------------------------------------------------------------------------
+
+# ----------------------------------------------------------------------------
+# Maven Start Up Batch script
+#
+# Required ENV vars:
+# ------------------
+#   JAVA_HOME - location of a JDK home dir
+#
+# Optional ENV vars
+# -----------------
+#   M2_HOME - location of maven2's installed home dir
+#   MAVEN_OPTS - parameters passed to the Java VM when running Maven
+#     e.g. to debug Maven itself, use
+#       set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+#   MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+# ----------------------------------------------------------------------------
+
+if [ -z "$MAVEN_SKIP_RC" ] ; then
+
+  if [ -f /etc/mavenrc ] ; then
+    . /etc/mavenrc
+  fi
+
+  if [ -f "$HOME/.mavenrc" ] ; then
+    . "$HOME/.mavenrc"
+  fi
+
+fi
+
+# OS specific support.  $var _must_ be set to either true or false.
+cygwin=false;
+darwin=false;
+mingw=false
+case "`uname`" in
+  CYGWIN*) cygwin=true ;;
+  MINGW*) mingw=true;;
+  Darwin*) darwin=true
+    # Use /usr/libexec/java_home if available, otherwise fall back to /Library/Java/Home
+    # See https://developer.apple.com/library/mac/qa/qa1170/_index.html
+    if [ -z "$JAVA_HOME" ]; then
+      if [ -x "/usr/libexec/java_home" ]; then
+        export JAVA_HOME="`/usr/libexec/java_home`"
+      else
+        export JAVA_HOME="/Library/Java/Home"
+      fi
+    fi
+    ;;
+esac
+
+if [ -z "$JAVA_HOME" ] ; then
+  if [ -r /etc/gentoo-release ] ; then
+    JAVA_HOME=`java-config --jre-home`
+  fi
+fi
+
+if [ -z "$M2_HOME" ] ; then
+  ## resolve links - $0 may be a link to maven's home
+  PRG="$0"
+
+  # need this for relative symlinks
+  while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+      PRG="$link"
+    else
+      PRG="`dirname "$PRG"`/$link"
+    fi
+  done
+
+  saveddir=`pwd`
+
+  M2_HOME=`dirname "$PRG"`/..
+
+  # make it fully qualified
+  M2_HOME=`cd "$M2_HOME" && pwd`
+
+  cd "$saveddir"
+  # echo Using m2 at $M2_HOME
+fi
+
+# For Cygwin, ensure paths are in UNIX format before anything is touched
+if $cygwin ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --unix "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
+fi
+
+# For Mingw, ensure paths are in UNIX format before anything is touched
+if $mingw ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME="`(cd "$M2_HOME"; pwd)`"
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME="`(cd "$JAVA_HOME"; pwd)`"
+fi
+
+if [ -z "$JAVA_HOME" ]; then
+  javaExecutable="`which javac`"
+  if [ -n "$javaExecutable" ] && ! [ "`expr \"$javaExecutable\" : '\([^ ]*\)'`" = "no" ]; then
+    # readlink(1) is not available as standard on Solaris 10.
+    readLink=`which readlink`
+    if [ ! `expr "$readLink" : '\([^ ]*\)'` = "no" ]; then
+      if $darwin ; then
+        javaHome="`dirname \"$javaExecutable\"`"
+        javaExecutable="`cd \"$javaHome\" && pwd -P`/javac"
+      else
+        javaExecutable="`readlink -f \"$javaExecutable\"`"
+      fi
+      javaHome="`dirname \"$javaExecutable\"`"
+      javaHome=`expr "$javaHome" : '\(.*\)/bin'`
+      JAVA_HOME="$javaHome"
+      export JAVA_HOME
+    fi
+  fi
+fi
+
+if [ -z "$JAVACMD" ] ; then
+  if [ -n "$JAVA_HOME"  ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+      # IBM's JDK on AIX uses strange locations for the executables
+      JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+      JAVACMD="$JAVA_HOME/bin/java"
+    fi
+  else
+    JAVACMD="`which java`"
+  fi
+fi
+
+if [ ! -x "$JAVACMD" ] ; then
+  echo "Error: JAVA_HOME is not defined correctly." >&2
+  echo "  We cannot execute $JAVACMD" >&2
+  exit 1
+fi
+
+if [ -z "$JAVA_HOME" ] ; then
+  echo "Warning: JAVA_HOME environment variable is not set."
+fi
+
+CLASSWORLDS_LAUNCHER=org.codehaus.plexus.classworlds.launcher.Launcher
+
+# traverses directory structure from process work directory to filesystem root
+# first directory with .mvn subdirectory is considered project base directory
+find_maven_basedir() {
+
+  if [ -z "$1" ]
+  then
+    echo "Path not specified to find_maven_basedir"
+    return 1
+  fi
+
+  basedir="$1"
+  wdir="$1"
+  while [ "$wdir" != '/' ] ; do
+    if [ -d "$wdir"/.mvn ] ; then
+      basedir=$wdir
+      break
+    fi
+    # workaround for JBEAP-8937 (on Solaris 10/Sparc)
+    if [ -d "${wdir}" ]; then
+      wdir=`cd "$wdir/.."; pwd`
+    fi
+    # end of workaround
+  done
+  echo "${basedir}"
+}
+
+# concatenates all lines of a file
+concat_lines() {
+  if [ -f "$1" ]; then
+    echo "$(tr -s '\n' ' ' < "$1")"
+  fi
+}
+
+BASE_DIR=`find_maven_basedir "$(pwd)"`
+if [ -z "$BASE_DIR" ]; then
+  exit 1;
+fi
+
+##########################################################################################
+# Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+# This allows using the maven wrapper in projects that prohibit checking in binary data.
+##########################################################################################
+if [ -r "$BASE_DIR/.mvn/wrapper/maven-wrapper.jar" ]; then
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Found .mvn/wrapper/maven-wrapper.jar"
+    fi
+else
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Couldn't find .mvn/wrapper/maven-wrapper.jar, downloading it ..."
+    fi
+    if [ -n "$MVNW_REPOURL" ]; then
+      jarUrl="$MVNW_REPOURL/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    else
+      jarUrl="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    fi
+    while IFS="=" read key value; do
+      case "$key" in (wrapperUrl) jarUrl="$value"; break ;;
+      esac
+    done < "$BASE_DIR/.mvn/wrapper/maven-wrapper.properties"
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Downloading from: $jarUrl"
+    fi
+    wrapperJarPath="$BASE_DIR/.mvn/wrapper/maven-wrapper.jar"
+    if $cygwin; then
+      wrapperJarPath=`cygpath --path --windows "$wrapperJarPath"`
+    fi
+
+    if command -v wget > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found wget ... using wget"
+        fi
+        if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
+            wget "$jarUrl" -O "$wrapperJarPath"
+        else
+            wget --http-user=$MVNW_USERNAME --http-password=$MVNW_PASSWORD "$jarUrl" -O "$wrapperJarPath"
+        fi
+    elif command -v curl > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found curl ... using curl"
+        fi
+        if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
+            curl -o "$wrapperJarPath" "$jarUrl" -f
+        else
+            curl --user $MVNW_USERNAME:$MVNW_PASSWORD -o "$wrapperJarPath" "$jarUrl" -f
+        fi
+
+    else
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Falling back to using Java to download"
+        fi
+        javaClass="$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.java"
+        # For Cygwin, switch paths to Windows format before running javac
+        if $cygwin; then
+          javaClass=`cygpath --path --windows "$javaClass"`
+        fi
+        if [ -e "$javaClass" ]; then
+            if [ ! -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Compiling MavenWrapperDownloader.java ..."
+                fi
+                # Compiling the Java class
+                ("$JAVA_HOME/bin/javac" "$javaClass")
+            fi
+            if [ -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                # Running the downloader
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Running MavenWrapperDownloader.java ..."
+                fi
+                ("$JAVA_HOME/bin/java" -cp .mvn/wrapper MavenWrapperDownloader "$MAVEN_PROJECTBASEDIR")
+            fi
+        fi
+    fi
+fi
+##########################################################################################
+# End of extension
+##########################################################################################
+
+export MAVEN_PROJECTBASEDIR=${MAVEN_BASEDIR:-"$BASE_DIR"}
+if [ "$MVNW_VERBOSE" = true ]; then
+  echo $MAVEN_PROJECTBASEDIR
+fi
+MAVEN_OPTS="$(concat_lines "$MAVEN_PROJECTBASEDIR/.mvn/jvm.config") $MAVEN_OPTS"
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --path --windows "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --path --windows "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
+  [ -n "$MAVEN_PROJECTBASEDIR" ] &&
+    MAVEN_PROJECTBASEDIR=`cygpath --path --windows "$MAVEN_PROJECTBASEDIR"`
+fi
+
+# Provide a "standardized" way to retrieve the CLI args that will
+# work with both Windows and non-Windows executions.
+MAVEN_CMD_LINE_ARGS="$MAVEN_CONFIG $@"
+export MAVEN_CMD_LINE_ARGS
+
+WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+exec "$JAVACMD" \
+  $MAVEN_OPTS \
+  -classpath "$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.jar" \
+  "-Dmaven.home=${M2_HOME}" "-Dmaven.multiModuleProjectDirectory=${MAVEN_PROJECTBASEDIR}" \
+  ${WRAPPER_LAUNCHER} $MAVEN_CONFIG "$@"

core-java/heapdump/mvnw.cmd

@@ -0,0 +1,182 @@
+@REM ----------------------------------------------------------------------------
+@REM Licensed to the Apache Software Foundation (ASF) under one
+@REM or more contributor license agreements.  See the NOTICE file
+@REM distributed with this work for additional information
+@REM regarding copyright ownership.  The ASF licenses this file
+@REM to you under the Apache License, Version 2.0 (the
+@REM "License"); you may not use this file except in compliance
+@REM with the License.  You may obtain a copy of the License at
+@REM
+@REM    http://www.apache.org/licenses/LICENSE-2.0
+@REM
+@REM Unless required by applicable law or agreed to in writing,
+@REM software distributed under the License is distributed on an
+@REM "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+@REM KIND, either express or implied.  See the License for the
+@REM specific language governing permissions and limitations
+@REM under the License.
+@REM ----------------------------------------------------------------------------
+
+@REM ----------------------------------------------------------------------------
+@REM Maven Start Up Batch script
+@REM
+@REM Required ENV vars:
+@REM JAVA_HOME - location of a JDK home dir
+@REM
+@REM Optional ENV vars
+@REM M2_HOME - location of maven2's installed home dir
+@REM MAVEN_BATCH_ECHO - set to 'on' to enable the echoing of the batch commands
+@REM MAVEN_BATCH_PAUSE - set to 'on' to wait for a keystroke before ending
+@REM MAVEN_OPTS - parameters passed to the Java VM when running Maven
+@REM     e.g. to debug Maven itself, use
+@REM set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+@REM MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+@REM ----------------------------------------------------------------------------
+
+@REM Begin all REM lines with '@' in case MAVEN_BATCH_ECHO is 'on'
+@echo off
+@REM set title of command window
+title %0
+@REM enable echoing by setting MAVEN_BATCH_ECHO to 'on'
+@if "%MAVEN_BATCH_ECHO%" == "on"  echo %MAVEN_BATCH_ECHO%
+
+@REM set %HOME% to equivalent of $HOME
+if "%HOME%" == "" (set "HOME=%HOMEDRIVE%%HOMEPATH%")
+
+@REM Execute a user defined script before this one
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPre
+@REM check for pre script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_pre.bat" call "%HOME%\mavenrc_pre.bat"
+if exist "%HOME%\mavenrc_pre.cmd" call "%HOME%\mavenrc_pre.cmd"
+:skipRcPre
+
+@setlocal
+
+set ERROR_CODE=0
+
+@REM To isolate internal variables from possible post scripts, we use another setlocal
+@setlocal
+
+@REM ==== START VALIDATION ====
+if not "%JAVA_HOME%" == "" goto OkJHome
+
+echo.
+echo Error: JAVA_HOME not found in your environment. >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+:OkJHome
+if exist "%JAVA_HOME%\bin\java.exe" goto init
+
+echo.
+echo Error: JAVA_HOME is set to an invalid directory. >&2
+echo JAVA_HOME = "%JAVA_HOME%" >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+@REM ==== END VALIDATION ====
+
+:init
+
+@REM Find the project base dir, i.e. the directory that contains the folder ".mvn".
+@REM Fallback to current working directory if not found.
+
+set MAVEN_PROJECTBASEDIR=%MAVEN_BASEDIR%
+IF NOT "%MAVEN_PROJECTBASEDIR%"=="" goto endDetectBaseDir
+
+set EXEC_DIR=%CD%
+set WDIR=%EXEC_DIR%
+:findBaseDir
+IF EXIST "%WDIR%"\.mvn goto baseDirFound
+cd ..
+IF "%WDIR%"=="%CD%" goto baseDirNotFound
+set WDIR=%CD%
+goto findBaseDir
+
+:baseDirFound
+set MAVEN_PROJECTBASEDIR=%WDIR%
+cd "%EXEC_DIR%"
+goto endDetectBaseDir
+
+:baseDirNotFound
+set MAVEN_PROJECTBASEDIR=%EXEC_DIR%
+cd "%EXEC_DIR%"
+
+:endDetectBaseDir
+
+IF NOT EXIST "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" goto endReadAdditionalConfig
+
+@setlocal EnableExtensions EnableDelayedExpansion
+for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do set JVM_CONFIG_MAVEN_PROPS=!JVM_CONFIG_MAVEN_PROPS! %%a
+@endlocal & set JVM_CONFIG_MAVEN_PROPS=%JVM_CONFIG_MAVEN_PROPS%
+
+:endReadAdditionalConfig
+
+SET MAVEN_JAVA_EXE="%JAVA_HOME%\bin\java.exe"
+set WRAPPER_JAR="%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.jar"
+set WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+set DOWNLOAD_URL="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+
+FOR /F "tokens=1,2 delims==" %%A IN ("%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.properties") DO (
+    IF "%%A"=="wrapperUrl" SET DOWNLOAD_URL=%%B
+)
+
+@REM Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+@REM This allows using the maven wrapper in projects that prohibit checking in binary data.
+if exist %WRAPPER_JAR% (
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Found %WRAPPER_JAR%
+    )
+) else (
+    if not "%MVNW_REPOURL%" == "" (
+        SET DOWNLOAD_URL="%MVNW_REPOURL%/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    )
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Couldn't find %WRAPPER_JAR%, downloading it ...
+        echo Downloading from: %DOWNLOAD_URL%
+    )
+
+    powershell -Command "&{"^
+		"$webclient = new-object System.Net.WebClient;"^
+		"if (-not ([string]::IsNullOrEmpty('%MVNW_USERNAME%') -and [string]::IsNullOrEmpty('%MVNW_PASSWORD%'))) {"^
+		"$webclient.Credentials = new-object System.Net.NetworkCredential('%MVNW_USERNAME%', '%MVNW_PASSWORD%');"^
+		"}"^
+		"[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; $webclient.DownloadFile('%DOWNLOAD_URL%', '%WRAPPER_JAR%')"^
+		"}"
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Finished downloading %WRAPPER_JAR%
+    )
+)
+@REM End of extension
+
+@REM Provide a "standardized" way to retrieve the CLI args that will
+@REM work with both Windows and non-Windows executions.
+set MAVEN_CMD_LINE_ARGS=%*
+
+%MAVEN_JAVA_EXE% %JVM_CONFIG_MAVEN_PROPS% %MAVEN_OPTS% %MAVEN_DEBUG_OPTS% -classpath %WRAPPER_JAR% "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" %WRAPPER_LAUNCHER% %MAVEN_CONFIG% %*
+if ERRORLEVEL 1 goto error
+goto end
+
+:error
+set ERROR_CODE=1
+
+:end
+@endlocal & set ERROR_CODE=%ERROR_CODE%
+
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPost
+@REM check for post script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_post.bat" call "%HOME%\mavenrc_post.bat"
+if exist "%HOME%\mavenrc_post.cmd" call "%HOME%\mavenrc_post.cmd"
+:skipRcPost
+
+@REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
+if "%MAVEN_BATCH_PAUSE%" == "on" pause
+
+if "%MAVEN_TERMINATE_CMD%" == "on" exit %ERROR_CODE%
+
+exit /B %ERROR_CODE%

core-java/heapdump/pom.xml

@@ -0,0 +1,32 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>io.pratik</groupId>
+	<artifactId>oomegen</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>oomegen</name>
+	<properties>
+		<maven.compiler.source>11</maven.compiler.source>
+		<maven.compiler.target>11</maven.compiler.target>
+	</properties>
+
+	<build>
+		<plugins>
+			<plugin>
+				<!-- Build an executable JAR -->
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-jar-plugin</artifactId>
+				<version>2.4</version>
+				<configuration>
+					<archive>
+						<manifest>
+							<mainClass>io.pratik.OOMGenerator</mainClass>
+						</manifest>
+					</archive>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

core-java/heapdump/src/main/java/io/pratik/AbstractProduct.java

@@ -0,0 +1,54 @@
+/**
+ * 
+ */
+package io.pratik;
+
+import java.util.Random;
+import java.util.UUID;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class AbstractProduct {
+
+	private String name;
+	private String id;
+	private byte[] logo;
+	private static final Random random = new Random();
+
+	public AbstractProduct() {
+		super();
+		this.id = UUID.randomUUID().toString();
+		this.logo = new byte[(5 ) * 1024 * 1024];
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public String getId() {
+		return id;
+	}
+
+	public void setId(String id) {
+		this.id = id;
+	}
+
+	public byte[] getLogo() {
+		return logo;
+	}
+
+	public void setLogo(byte[] logo) {
+		this.logo = logo;
+	}
+
+	public long getSize() {
+		return JavaAgent.getObjectSize(this) + JavaAgent.getObjectSize(logo) + JavaAgent.getObjectSize(id);
+	}
+
+}

core-java/heapdump/src/main/java/io/pratik/JavaAgent.java

@@ -0,0 +1,23 @@
+/**
+ * 
+ */
+package io.pratik;
+
+import java.lang.instrument.Instrumentation;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class JavaAgent {
+    private static volatile Instrumentation instrumentation;
+    public static void premain(final String agentArgs, final Instrumentation instrumentation) {
+        JavaAgent.instrumentation = instrumentation;
+    }
+    public static long getObjectSize(final Object object) {
+        if (instrumentation == null) {
+            return -1L;
+        }
+        return instrumentation.getObjectSize(object);
+    }
+}

core-java/heapdump/src/main/java/io/pratik/OOMGenerator.java

@@ -0,0 +1,29 @@
+/**
+ * 
+ */
+package io.pratik;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class OOMGenerator {
+
+	/**
+	 * @param args
+	 * @throws Exception
+	 */
+	public static void main(String[] args) throws Exception {
+		
+		System.out.println("Max JVM memory: " + Runtime.getRuntime().maxMemory()/(1024*1024));
+		try {
+			ProductManager productManager = new ProductManager();
+			productManager.populateProducts();
+			
+		} catch (OutOfMemoryError outofMemory) {
+			System.out.println("Catching out of memory error "+ Runtime.getRuntime().freeMemory()/(1024*1024));
+			// Log the information,so that we can generate the statistics (latter on).
+			throw outofMemory;
+		}
+	}
+}

core-java/heapdump/src/main/java/io/pratik/ProductManager.java

@@ -0,0 +1,58 @@
+/**
+ * 
+ */
+package io.pratik;
+
+import io.pratik.models.BrandedProduct;
+import io.pratik.models.ElectronicGood;
+import io.pratik.models.GroceryProduct;
+import io.pratik.models.LuxuryGood;
+import io.pratik.models.ProductGroup;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class ProductManager {
+	private ProductGroup regularItems = new ProductGroup();
+
+	private ProductGroup discountedItems = new ProductGroup();
+
+	public void populateProducts() {
+
+		int dummyArraySize = 1;
+		for (int loop = 0; loop < 10; loop++) {
+			if(loop%2 == 0) {
+			  createObjects(regularItems, dummyArraySize);
+			}else {
+			  createObjects(discountedItems, dummyArraySize);
+			}
+			System.out.println("Memory Consumed till now: " + loop + "::"+ regularItems + " "+discountedItems );
+			dummyArraySize *= dummyArraySize * 2;
+		}
+	}
+
+	private void createObjects(ProductGroup productGroup, int dummyArraySize) {
+		for (int i = 0; i < dummyArraySize; ) {
+			productGroup.add(createProduct());
+		}
+ 	}
+	
+	private AbstractProduct createProduct() {
+        int randomIndex = (int) Math.round(Math.random() * 10);
+        switch (randomIndex) {
+		case 0:
+			return  new ElectronicGood();
+		case 1:
+			return	new BrandedProduct();
+		case 2:
+			return new GroceryProduct();
+		case 3:
+			return new LuxuryGood();
+		default:
+			return	new BrandedProduct();
+		}
+		
+	}
+
+}

core-java/heapdump/src/main/java/io/pratik/models/BrandedProduct.java

@@ -0,0 +1,48 @@
+/**
+ * 
+ */
+package io.pratik.models;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import io.pratik.AbstractProduct;
+import io.pratik.JavaAgent;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class BrandedProduct extends AbstractProduct{
+	private String brandName;
+	private Price mrp;
+	
+	
+
+	public BrandedProduct() {
+		super();
+		mrp = new Price();
+
+	}
+
+	public Price getMrp() {
+		return mrp;
+	}
+
+	public void setMrp(Price mrp) {
+		this.mrp = mrp;
+	}
+
+	public String getBrandName() {
+		return brandName;
+	}
+
+	public void setBrandName(String brandName) {
+		this.brandName = brandName;
+	}
+	
+	public long getSize() {
+		return JavaAgent.getObjectSize(this) + JavaAgent.getObjectSize(brandName);
+	}
+    
+}

core-java/heapdump/src/main/java/io/pratik/models/ElectronicGood.java

@@ -0,0 +1,31 @@
+/**
+ * 
+ */
+package io.pratik.models;
+
+import io.pratik.AbstractProduct;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class ElectronicGood extends AbstractProduct{
+	
+	private Manufacturer manufacturer;
+	
+	
+
+	public ElectronicGood() {
+		super();
+		this.manufacturer = new Manufacturer();
+	}
+
+	public Manufacturer getManufacturer() {
+		return manufacturer;
+	}
+
+	public void setManufacturer(Manufacturer manufacturer) {
+		this.manufacturer = manufacturer;
+	}
+	
+}

core-java/heapdump/src/main/java/io/pratik/models/GroceryProduct.java

@@ -0,0 +1,35 @@
+/**
+ * 
+ */
+package io.pratik.models;
+
+import io.pratik.AbstractProduct;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class GroceryProduct extends AbstractProduct{
+	private Price mrp;
+	private Price discountedPrice;
+	
+	
+	public GroceryProduct() {
+		super();
+		mrp = new Price();
+		discountedPrice = new Price();
+	}
+	public Price getMrp() {
+		return mrp;
+	}
+	public void setMrp(Price mrp) {
+		this.mrp = mrp;
+	}
+	public Price getDiscountedPrice() {
+		return discountedPrice;
+	}
+	public void setDiscountedPrice(Price discountedPrice) {
+		this.discountedPrice = discountedPrice;
+	}
+
+}

core-java/heapdump/src/main/java/io/pratik/models/LuxuryGood.java

@@ -0,0 +1,25 @@
+/**
+ * 
+ */
+package io.pratik.models;
+
+import io.pratik.AbstractProduct;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class LuxuryGood extends AbstractProduct{
+	private String luxuryCategory;
+
+	public String getLuxuryCategory() {
+		return luxuryCategory;
+	}
+
+	public void setLuxuryCategory(String luxuryCategory) {
+		this.luxuryCategory = luxuryCategory;
+	}
+	
+	
+
+}

core-java/heapdump/src/main/java/io/pratik/models/Manufacturer.java

@@ -0,0 +1,43 @@
+/**
+ * 
+ */
+package io.pratik.models;
+
+import io.pratik.JavaAgent;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class Manufacturer {
+	
+	private String name;
+	private String address;
+	
+	
+	public Manufacturer() {
+		super();
+		this.name = "Dummy";
+		this.address = "dummy state";
+	}
+	public String getName() {
+		return name;
+	}
+	public void setName(String name) {
+		this.name = name;
+	}
+	public String getAddress() {
+		return address;
+	}
+	public void setAddress(String address) {
+		this.address = address;
+	}
+	
+	public long getSize() {
+		return JavaAgent.getObjectSize(this) 
+				+ JavaAgent.getObjectSize(name) 
+				+ JavaAgent.getObjectSize(address);
+	}
+	
+
+}

core-java/heapdump/src/main/java/io/pratik/models/Price.java

@@ -0,0 +1,45 @@
+/**
+ * 
+ */
+package io.pratik.models;
+
+import java.util.Date;
+
+import io.pratik.JavaAgent;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public final class Price {
+	
+	private Double value;
+	private Date lastUpdated;
+	
+	
+	public Price() {
+		super();
+		value = 48.0;
+		lastUpdated = new Date();
+		
+	}
+	public Double getValue() {
+		return value;
+	}
+	public void setValue(Double value) {
+		this.value = value;
+	}
+	public Date getLastUpdated() {
+		return lastUpdated;
+	}
+	public void setLastUpdated(Date lastUpdated) {
+		this.lastUpdated = lastUpdated;
+	}
+	
+	public long getSize() {
+		return JavaAgent.getObjectSize(this) 
+				+ JavaAgent.getObjectSize(value) 
+				+ JavaAgent.getObjectSize(lastUpdated.toString());
+	}
+
+}

core-java/heapdump/src/main/java/io/pratik/models/ProductGroup.java

@@ -0,0 +1,22 @@
+/**
+ * 
+ */
+package io.pratik.models;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import io.pratik.AbstractProduct;
+
+/**
+ * @author Pratik Das
+ *
+ */
+public class ProductGroup {
+	
+	private List<AbstractProduct> products = new ArrayList<AbstractProduct>();
+	
+	public void add(AbstractProduct product) {
+		products.add(product);
+	}
+}

core-java/heapdump/src/main/resources/META-INF/MANIFEST.MF

@@ -0,0 +1,2 @@
+Manifest-Version: 1.0
+Premain-Class: io.pratik.JavaAgent

core-java/service-provider-interface/.gitignore

@@ -0,0 +1,2 @@
+/.idea
+**/target

core-java/service-provider-interface/.mvn/wrapper/MavenWrapperDownloader.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2007-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import java.net.*;
+import java.io.*;
+import java.nio.channels.*;
+import java.util.Properties;
+
+public class MavenWrapperDownloader {
+
+    private static final String WRAPPER_VERSION = "0.5.6";
+    /**
+     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
+     */
+    private static final String DEFAULT_DOWNLOAD_URL = "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/"
+        + WRAPPER_VERSION + "/maven-wrapper-" + WRAPPER_VERSION + ".jar";
+
+    /**
+     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
+     * use instead of the default one.
+     */
+    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
+            ".mvn/wrapper/maven-wrapper.properties";
+
+    /**
+     * Path where the maven-wrapper.jar will be saved to.
+     */
+    private static final String MAVEN_WRAPPER_JAR_PATH =
+            ".mvn/wrapper/maven-wrapper.jar";
+
+    /**
+     * Name of the property which should be used to override the default download url for the wrapper.
+     */
+    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
+
+    public static void main(String args[]) {
+        System.out.println("- Downloader started");
+        File baseDirectory = new File(args[0]);
+        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
+
+        // If the maven-wrapper.properties exists, read it and check if it contains a custom
+        // wrapperUrl parameter.
+        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
+        String url = DEFAULT_DOWNLOAD_URL;
+        if(mavenWrapperPropertyFile.exists()) {
+            FileInputStream mavenWrapperPropertyFileInputStream = null;
+            try {
+                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
+                Properties mavenWrapperProperties = new Properties();
+                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
+                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
+            } catch (IOException e) {
+                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
+            } finally {
+                try {
+                    if(mavenWrapperPropertyFileInputStream != null) {
+                        mavenWrapperPropertyFileInputStream.close();
+                    }
+                } catch (IOException e) {
+                    // Ignore ...
+                }
+            }
+        }
+        System.out.println("- Downloading from: " + url);
+
+        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
+        if(!outputFile.getParentFile().exists()) {
+            if(!outputFile.getParentFile().mkdirs()) {
+                System.out.println(
+                        "- ERROR creating output directory '" + outputFile.getParentFile().getAbsolutePath() + "'");
+            }
+        }
+        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
+        try {
+            downloadFileFromURL(url, outputFile);
+            System.out.println("Done");
+            System.exit(0);
+        } catch (Throwable e) {
+            System.out.println("- Error downloading");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
+        if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
+            String username = System.getenv("MVNW_USERNAME");
+            char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
+            Authenticator.setDefault(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication(username, password);
+                }
+            });
+        }
+        URL website = new URL(urlString);
+        ReadableByteChannel rbc;
+        rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(destination);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        fos.close();
+        rbc.close();
+    }
+
+}

core-java/service-provider-interface/.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,2 @@
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar

core-java/service-provider-interface/README.md

@@ -0,0 +1,3 @@
+# Related Blog Posts
+
+* [Service Provider Interface](https://reflectoring.io/service-provider-interface/)

core-java/service-provider-interface/classics-library/pom.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>service-provider-interface</artifactId>
+        <groupId>org.library</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>classics-library</artifactId>
+
+    <name>classics-library</name>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.library</groupId>
+            <artifactId>library-service-provider</artifactId>
+            <version>1.0-SNAPSHOT</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+    </build>
+</project>

core-java/service-provider-interface/classics-library/src/main/java/org/library/ClassicsLibrary.java

@@ -0,0 +1,40 @@
+package org.library;
+
+import java.util.Map;
+import java.util.TreeMap;
+
+import org.library.spi.Book;
+import org.library.spi.Library;
+
+public class ClassicsLibrary implements Library {
+
+    public static final String CLASSICS_LIBRARY = "CLASSICS";
+    private final Map<String, Book> books;
+
+    public ClassicsLibrary() {
+        books = new TreeMap<>();
+        Book nineteenEightyFour = new Book("Nineteen Eighty-Four", "George Orwell",
+                "It was a bright cold day in April, and the clocks were striking thirteen.");
+        Book theLordOfTheRings = new Book("The Lord of the Rings", "J. R. R. Tolkien",
+                "When Mr. Bilbo Baggins of Bag End announced that he would shortly be celebrating his " +
+                        "eleventy-first birthday with a party of special magnificence, there was much talk and excitement in Hobbiton.");
+        Book cleanCode = new Book("Clean Code", "Robert C. Martin",
+                "ClassicsEven bad code can function. But if code isn’t clean, it can bring a development organization to its knees");
+
+        books.put("Nineteen Eighty-Four", nineteenEightyFour);
+        books.put("The Lord of the Rings", theLordOfTheRings);
+        books.put("Clean Code", cleanCode);
+    }
+
+    @Override
+    public String getCategory() {
+        return CLASSICS_LIBRARY;
+    }
+
+    @Override
+    public Book getBook(String name) {
+        return books.get(name);
+    }
+
+}
+

core-java/service-provider-interface/classics-library/src/main/resources/META-INF/services/org.library.spi.Library

@@ -0,0 +1 @@
+org.library.ClassicsLibrary

core-java/service-provider-interface/computer-science-library/pom.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.library</groupId>
+  <artifactId>computer-science-library</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <name>computer-science-library</name>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.library</groupId>
+      <artifactId>library-service-provider</artifactId>
+      <version>1.0-SNAPSHOT</version>
+    </dependency>
+  </dependencies>
+
+  <build>
+  </build>
+</project>