add source

lesson-1/.gitignore

@@ -0,0 +1 @@
+/.metadata/

lesson-1/README.md

@@ -0,0 +1,11 @@
+Lesson-1
+---
+A very basic sample of Axon framework.
+
+In this Sample, you will learn the basic concept of Axon and CQRS & EventSourcing.
+- Command
+- Event
+- CommandGateway
+- Command Handler
+- Event Handler
+

lesson-1/pom.xml

@@ -0,0 +1,16 @@
+<?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>sbs-axon</artifactId>
+        <groupId>com.edi.learn</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+
+    <modelVersion>4.0.0</modelVersion>
+    <packaging>jar</packaging>
+    <artifactId>lesson-1</artifactId>
+    <version>1</version>
+
+</project>

lesson-1/src/main/java/com/edi/learn/axon/Application.java

@@ -0,0 +1,34 @@
+package com.edi.learn.axon;
+
+
+import com.edi.learn.axon.command.aggregates.BankAccount;
+import com.edi.learn.axon.command.commands.CreateAccountCommand;
+import com.edi.learn.axon.command.commands.WithdrawMoneyCommand;
+import com.edi.learn.axon.common.domain.AccountId;
+import org.axonframework.config.Configuration;
+import org.axonframework.config.DefaultConfigurer;
+import org.axonframework.eventsourcing.eventstore.inmemory.InMemoryEventStorageEngine;
+import org.slf4j.Logger;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
+
+public class Application {
+
+    private static final Logger LOGGER = getLogger(Application.class);
+
+    public static void main(String args[]){
+        Configuration config = DefaultConfigurer.defaultConfiguration()
+                .configureAggregate(BankAccount.class)
+                .configureEmbeddedEventStore(c -> new InMemoryEventStorageEngine())
+                .buildConfiguration();
+        config.start();
+        AccountId id = new AccountId();
+        config.commandGateway().send(new CreateAccountCommand(id, "MyAccount",1000));
+        config.commandGateway().send(new WithdrawMoneyCommand(id, 500));
+        config.commandGateway().send(new WithdrawMoneyCommand(id, 500));
+        /*config.commandBus().dispatch(asCommandMessage(new CreateAccountCommand(id, "MyAccount", 1000)));
+        config.commandBus().dispatch(asCommandMessage(new WithdrawMoneyCommand(id, 500)));*/
+    }
+
+}

lesson-1/src/main/java/com/edi/learn/axon/command/aggregates/BankAccount.java

@@ -0,0 +1,60 @@
+package com.edi.learn.axon.command.aggregates;
+
+import com.edi.learn.axon.command.commands.CreateAccountCommand;
+import com.edi.learn.axon.command.commands.WithdrawMoneyCommand;
+import com.edi.learn.axon.common.domain.AccountId;
+import com.edi.learn.axon.common.events.AccountCreatedEvent;
+import com.edi.learn.axon.common.events.MoneyWithdrawnEvent;
+import org.axonframework.commandhandling.CommandHandler;
+import org.axonframework.commandhandling.model.AggregateIdentifier;
+import org.axonframework.eventhandling.EventHandler;
+import org.slf4j.Logger;
+
+import java.math.BigDecimal;
+
+import static org.axonframework.commandhandling.model.AggregateLifecycle.apply;
+import static org.slf4j.LoggerFactory.getLogger;
+
+
+public class BankAccount {
+
+    private static final Logger LOGGER = getLogger(BankAccount.class);
+
+    @AggregateIdentifier
+    private AccountId accountId;
+    private String accountName;
+    private BigDecimal balance;
+
+    public BankAccount() {
+    }
+
+    @CommandHandler
+    public BankAccount(CreateAccountCommand command){
+        LOGGER.debug("Construct a new BankAccount");
+        apply(new AccountCreatedEvent(command.getAccountId(), command.getAccountName(), command.getAmount()));
+    }
+
+    @CommandHandler
+    public void handle(WithdrawMoneyCommand command){
+        apply(new MoneyWithdrawnEvent(command.getAccountId(), command.getAmount()));
+    }
+
+    @EventHandler
+    public void on(AccountCreatedEvent event){
+        this.accountId = event.getAccountId();
+        this.accountName = event.getAccountName();
+        this.balance = new BigDecimal(event.getAmount());
+        LOGGER.info("Account {} is created with balance {}", accountId, this.balance);
+    }
+
+    @EventHandler
+    public void on(MoneyWithdrawnEvent event){
+        BigDecimal result = this.balance.subtract(new BigDecimal(event.getAmount()));
+        if(result.compareTo(BigDecimal.ZERO)<0)
+            LOGGER.error("Cannot withdraw more money than the balance!");
+        else {
+            this.balance = result;
+            LOGGER.info("Withdraw {} from account {}, balance result: {}", event.getAmount(), accountId, balance);
+        }
+    }
+}

lesson-1/src/main/java/com/edi/learn/axon/command/commands/CreateAccountCommand.java

@@ -0,0 +1,29 @@
+package com.edi.learn.axon.command.commands;
+
+import com.edi.learn.axon.common.domain.AccountId;
+
+
+public class CreateAccountCommand {
+
+    private AccountId accountId;
+    private String accountName;
+    private long amount;
+
+    public CreateAccountCommand(AccountId accountId, String accountName, long amount) {
+        this.accountId = accountId;
+        this.accountName = accountName;
+        this.amount = amount;
+    }
+
+    public AccountId getAccountId() {
+        return accountId;
+    }
+
+    public String getAccountName() {
+        return accountName;
+    }
+
+    public long getAmount() {
+        return amount;
+    }
+}

lesson-1/src/main/java/com/edi/learn/axon/command/commands/WithdrawMoneyCommand.java

@@ -0,0 +1,26 @@
+package com.edi.learn.axon.command.commands;
+
+import com.edi.learn.axon.common.domain.AccountId;
+import org.axonframework.commandhandling.TargetAggregateIdentifier;
+
+
+public class WithdrawMoneyCommand {
+
+    @TargetAggregateIdentifier
+    private AccountId accountId;
+    private long amount;
+
+
+    public WithdrawMoneyCommand(AccountId accountId, long amount) {
+        this.accountId = accountId;
+        this.amount = amount;
+    }
+
+    public AccountId getAccountId() {
+        return accountId;
+    }
+
+    public long getAmount() {
+        return amount;
+    }
+}

lesson-1/src/main/java/com/edi/learn/axon/common/domain/AccountId.java

@@ -0,0 +1,48 @@
+package com.edi.learn.axon.common.domain;
+
+import org.axonframework.common.Assert;
+import org.axonframework.common.IdentifierFactory;
+
+import java.io.Serializable;
+
+
+public class AccountId implements Serializable {
+
+    private static final long serialVersionUID = 7119961474083133148L;
+    private final String identifier;
+
+    private final int hashCode;
+
+    public AccountId() {
+        this.identifier = IdentifierFactory.getInstance().generateIdentifier();
+        this.hashCode = identifier.hashCode();
+    }
+
+    public AccountId(String identifier) {
+        Assert.notNull(identifier, ()->"Identifier may not be null");
+        this.identifier = identifier;
+        this.hashCode = identifier.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        AccountId accountId = (AccountId) o;
+
+        return identifier.equals(accountId.identifier);
+
+    }
+
+    @Override
+    public int hashCode() {
+        return hashCode;
+    }
+
+    @Override
+    public String toString() {
+        return identifier;
+    }
+
+}

lesson-1/src/main/java/com/edi/learn/axon/common/events/AccountCreatedEvent.java

@@ -0,0 +1,28 @@
+package com.edi.learn.axon.common.events;
+
+import com.edi.learn.axon.common.domain.AccountId;
+
+
+public class AccountCreatedEvent {
+    private AccountId accountId;
+    private String accountName;
+    private long amount;
+
+    public AccountCreatedEvent(AccountId accountId, String accountName, long amount) {
+        this.accountId = accountId;
+        this.accountName = accountName;
+        this.amount = amount;
+    }
+
+    public AccountId getAccountId() {
+        return accountId;
+    }
+
+    public String getAccountName() {
+        return accountName;
+    }
+
+    public long getAmount() {
+        return amount;
+    }
+}

lesson-1/src/main/java/com/edi/learn/axon/common/events/MoneyWithdrawnEvent.java

@@ -0,0 +1,22 @@
+package com.edi.learn.axon.common.events;
+
+import com.edi.learn.axon.common.domain.AccountId;
+
+
+public class MoneyWithdrawnEvent {
+    private AccountId accountId;
+    private long amount;
+
+    public MoneyWithdrawnEvent(AccountId accountId, long amount) {
+        this.accountId = accountId;
+        this.amount = amount;
+    }
+
+    public AccountId getAccountId() {
+        return accountId;
+    }
+
+    public long getAmount() {
+        return amount;
+    }
+}

lesson-1/src/main/resources/logback.xml

@@ -0,0 +1,14 @@
+<configuration>
+
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <!-- encoders are assigned the type
+             ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="info">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>