Full example code and resources

core-java/streams/fileswithstreams/pom.xml

@@ -1,8 +1,19 @@
-<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">
+<project xmlns="http://maven.apache.org/POM/4.0.0"
-  <modelVersion>4.0.0</modelVersion>
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  <groupId>fileswithstreams</groupId>
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
-  <artifactId>fileswithstreams</artifactId>
+	<modelVersion>4.0.0</modelVersion>
-  <version>0.0.1-SNAPSHOT</version>
+	<groupId>fileswithstreams</groupId>
-  <name>fileswithstreams</name>
+	<artifactId>fileswithstreams</artifactId>
-  <description>File management with streams</description>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>fileswithstreams</name>
+	<description>File management with streams</description>
+	<dependencies>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>4.13</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
 </project>

core-java/streams/fileswithstreams/src/main/java/io/reflectoring/fileswithstreams/Cake.java

@@ -0,0 +1,18 @@
+package io.reflectoring.fileswithstreams;
+
+public class Cake {
+    private int id;
+    private String name;
+    private int price;
+    
+    public Cake(int id, String name, int price) {
+    	this.id = id;
+    	this.name = name;
+    	this.price = price;
+    }
+
+	@Override
+	public String toString() {
+		return "Cake [id=" + id + ", name=" + name + ", price=" + price + "]";
+	}
+}

core-java/streams/fileswithstreams/src/main/java/io/reflectoring/fileswithstreams/FilesWithStreams.java

@@ -1,30 +1,100 @@
 package io.reflectoring.fileswithstreams;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Optional;
+import java.util.Set;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 public class FilesWithStreams {
-	public static final String fileName = "src/main/resources/paths.properties";
+	
 	static String folderPath = "src/main/resources/books";
 	static String filePath = "src/main/resources/books/bookIndex.txt";
-	static String jarFile = "src/main/resources/books/books.zip";
+	static String csvPath = "src/main/resources/cakes.csv";
+	static String utfFilePath = "src/main/resources/input.txt";
+	static String jarFile = "src/main/resources/books.zip";
 
 	public static void main(String[] args) throws IOException {
-		// processWithStream();
+		System.out.println("-------------------Files with Streams------------------ ");
-		// readLineByLineUsingFiles();
+		
+		System.out.println("-------------------Introductory Example------------------ ");
+
+		processWithStream();
+
+		System.out.println(
+				"\r\n" + "-------------------Example 1 - Reading line by line from a file------------------ " + "\r\n");
+
+		readLineByLineUsingFiles();
+
+		System.out.println(
+				"\r\n" + "-------------------Example 2 - Reading with Buffered Reader------------------" + "\r\n");
+
 		readLineByLineUsingBufferedReader();
-		readFilterCountUsingFiles();
+
-		// printJarFileContents();
+		System.out.println(
-		// printMatchingJarEntries();
+				"\r\n" + "-------------------Example 3 - Reading all lines from a file------------------ " + "\r\n");
-		// readWithParallelStreamAndPrint();
+
+		readAllLinesUsingFiles();
+
+		System.out.println(
+				"\r\n" + "...................Example 4 - Reading with parallel streams------------------ " + "\r\n");
+
+		readWithParallelStreamAndPrint();
+
+		System.out.println(
+				"\r\n" + "-------------------Example 5 - Reading UTF-encoded file------------------ " + "\r\n");
+
+		readUtfEncodedFile();
+
+		System.out.println(
+				"\r\n" + "-------------------Example 6 - Reading, Filtering and Counting------------------ " + "\r\n");
+
+		readFilterCountFromFile();
+
+		System.out.println("\r\n" + "-------------------Example 7 - Splitting Words------------------ " + "\r\n");
+
+		splitWordsFromFile();
+
+		System.out.println("\r\n" + "-------------------Example 8 - Loading from CSV - ------------------ " + "\r\n");
+
+		loadItemsFromCsvFile();
+
+		System.out.println("\r\n" + "...................Example 9 - Listing Directories------------------ " + "\r\n");
+
+		listDirectories();
+
+		System.out
+				.println("\r\n" + "...................Example 10 - Listing Regular Files------------------ " + "\r\n");
+
+		listRegularFiles();
+
+		System.out.println(
+				"\r\n" + "...................Example 11 - Walking Files Recursively------------------ " + "\r\n");
+
+		walkFilesRecursively();
+
+		System.out.println("\r\n" + "...................Example 12 - Finding Files------------------ " + "\r\n");
+
+		findFiles();
+
+		System.out.println(
+				"\r\n" + "...................Example 13 - Printing JAR fie contents------------------ " + "\r\n");
+
+		printJarFileContents();
+
+		System.out.println("...................Example 14 - Printing Matching JAR entries------------------ " + "\r\n");
+
+		printMatchingJarEntries();
+
 	}
 
 	static void processWithStream() {
@@ -44,15 +114,76 @@ public class FilesWithStreams {
 			lines.forEach(System.out::println);
 		}
 	}
-	
+
-	static void readFilterCountUsingFiles() throws IOException {
+	static void readAllLinesUsingFiles() throws IOException {
-		try (Stream<String> lines = Files.lines(Path.of(filePath))) {	
+		List<String> strList = Files.readAllLines(Path.of(filePath));
+		Stream<String> lines = strList.stream();
+		lines.forEach(System.out::println);
+	}
+
+	static void readUtfEncodedFile() throws IOException {
+		try (Stream<String> lines = Files.lines(Path.of(utfFilePath), StandardCharsets.UTF_8)) {
+			lines.forEach(System.out::println);
+		}
+	}
+
+	static void loadItemsFromCsvFile() throws IOException {
+		Pattern pattern = Pattern.compile(",");
+		try (Stream<String> lines = Files.lines(Path.of(csvPath))) {
+			List<Cake> cakes = lines.skip(1).map(line -> {
+				String[] arr = pattern.split(line);
+				return new Cake(Integer.parseInt(arr[0]), arr[1], Integer.parseInt(arr[2]));
+			}).collect(Collectors.toList());
+			cakes.forEach(System.out::println);
+		}
+	}
+
+	static void readFilterCountFromFile() throws IOException {
+		try (Stream<String> lines = Files.lines(Path.of(filePath))) {
 			long i = lines.filter(line -> line.startsWith("A")).count();
-			System.out.println("Count of lines starting with 'A' is " + i);
+			System.out.println("The count of lines starting with 'A' is " + i);
 
 		}
 	}
 
+	static void splitWordsFromFile() throws IOException {
+		try (Stream<String> lines = Files.lines(Path.of(filePath))) {
+			Stream<String> words = lines.flatMap(line -> Stream.of(line.split("\\W+")));
+			Set<String> wordSet = words.collect(Collectors.toSet());
+			System.out.println(wordSet);
+		}
+	}
+
+	static void listDirectories() throws IOException {
+		try (Stream<Path> paths = Files.list(Path.of(folderPath))) {
+			paths.filter(Files::isDirectory).forEach(System.out::println);
+		}
+	}
+
+	static void listRegularFiles() throws IOException {
+		try (Stream<Path> paths = Files.list(Path.of(folderPath))) {
+			paths.filter(Files::isRegularFile).forEach(System.out::println);
+		}
+	}
+
+	static void walkFilesRecursively() throws IOException {
+		try (Stream<Path> stream = Files.walk(Path.of(folderPath))) {
+			stream.filter(Files::isRegularFile).forEach(System.out::println);
+		}
+	}
+
+	static void findFiles() throws IOException {
+		int depth = Integer.MAX_VALUE;
+		try (Stream<Path> paths = Files.find(Path.of(folderPath), depth, (path, attr) -> {
+			return attr.isRegularFile() && path.toString().endsWith(".pdf");
+		})) {
+
+			paths.forEach(System.out::println);
+
+		}
+
+	}
+
 	static void printJarFileContents() throws IOException {
 		try (JarFile jFile = new JarFile(jarFile)) {
 			jFile.stream().forEach(file -> System.out.println(file));
@@ -70,10 +201,8 @@ public class FilesWithStreams {
 	}
 
 	static void readWithParallelStreamAndPrint() throws IOException {
-
+		try (Stream<String> lines = (Files.lines(Path.of(filePath)).parallel())) {
-		List<String> lines = Files.readAllLines(Path.of(filePath));
+			lines.forEach(System.out::println);
-		try (Stream<String> stream = lines.parallelStream()) {
-			stream.forEach(System.out::println);
 		}
 	}
 

core-java/streams/fileswithstreams/src/main/resources/cakes.csv

@@ -0,0 +1,6 @@
+#Cakes
+1, Pound Cake,100
+2, Red Velvet Cake,500
+3, Carrot Cake,300
+4, Sponge Cake,400
+5, Chiffon Cake,600

core-java/streams/fileswithstreams/src/main/resources/input.txt

@@ -1,4 +1 @@
-Master, you are the sole goal of human life
+akarui         _ あかるい  _   bright
-We are all but slaves of wishes
-Putting bar to our advancement
-You are the one and only true lord who can bring us upto that level