Describe Java scripting

Author: Nicolai Parlog

README.md

@@ -89,6 +89,7 @@ Check out the [jpms](http://blog.codefx.org/tag/jpms/) tag on my blog, [this dem
 
 ## JVM & Tooling
 
+* ⑪ [single-source-file execution](src/main/java/org/codefx/demo/java11/jvm/script) and scripting: run [the script](echo) with `cat echo-haiku.txt | ./echo` ([article](http://blog.codefx.org/java/scripting-java-shebang/), [JEP 330](https://openjdk.java.net/jeps/330))
 * ⑩ [application class-dara sharing](app-cds.sh) ([article](http://blog.codefx.org/java/application-class-data-sharing/), [JEP 310](http://openjdk.java.net/jeps/310))
 * ⑨ multi-release JARs: [classes](src/main/java/org/codefx/demo/java9/internal/multi_release) and [the script](multi-release.sh) ([JEP 238](http://openjdk.java.net/jeps/238))
 * ⑨ platform logging: [classes](src/platform_logging/java/org/codefx/demo/java9/api/platform_logging) and [the script](platform-logging.sh) ([JEP 264](http://openjdk.java.net/jeps/264))

echo

@@ -0,0 +1,46 @@
+#!/opt/jdk-11/bin/java --source 11
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Stream;
+
+public class Echo {
+
+	public static void main(String[] args) throws IOException {
+		var lines = readInput();
+		for (var arg : args)
+			lines = modifyStream(arg, lines);
+		lines.forEach(System.out::println);
+	}
+
+	private static Stream<String> modifyStream(String arg, Stream<String> input) {
+		switch (arg){
+			case "--sort": return input.sorted();
+			case "--unique": return input.distinct();
+			case "--reverse": return reverse(input);
+			default: {
+				System.out.println("Unknown argument '" + arg + "'.");
+				return input;
+			}
+		}
+	}
+
+	private static Stream<String> reverse(Stream<String> input) {
+		var reversed = new ArrayList<String>();
+		input.forEach(line -> reversed.add(0, line));
+		return reversed.stream();
+	}
+
+	private static Stream<String> readInput() throws IOException {
+		var reader = new BufferedReader(new InputStreamReader(System.in));
+		if (!reader.ready())
+			return Stream.empty();
+		else
+			return reader.lines();
+	}
+
+}

echo-haiku.txt

@@ -0,0 +1,3 @@
+worker bees can leave
+even drones can fly away
+the queen is their slave

src/main/java/org/codefx/demo/java11/jvm/script/Echo.java

@@ -0,0 +1,47 @@
+package org.codefx.demo.java11.jvm.script;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.stream.Stream;
+
+public class Echo {
+
+	public static void main(String[] args) throws IOException {
+		var lines = readInput();
+		for (var arg : args)
+			lines = modifyStream(arg, lines);
+		lines.forEach(System.out::println);
+	}
+
+	private static Stream<String> modifyStream(String arg, Stream<String> input) {
+		switch (arg){
+			case "--sort": return input.sorted();
+			case "--unique": return input.distinct();
+			case "--reverse": return reverse(input);
+			default: {
+				System.out.println("Unknown argument '" + arg + "'.");
+				return input;
+			}
+		}
+	}
+
+	private static Stream<String> reverse(Stream<String> input) {
+		var reversed = new ArrayList<String>();
+		input.forEach(line -> reversed.add(0, line));
+		return reversed.stream();
+	}
+
+	private static Stream<String> readInput() throws IOException {
+		var reader = new BufferedReader(new InputStreamReader(System.in));
+		if (!reader.ready())
+			return Stream.empty();
+		else
+			return reader.lines();
+	}
+
+}

src/main/java/org/codefx/demo/java11/jvm/script/HelloJavaScripts.java

@@ -0,0 +1,7 @@
+public class HelloJavaScripts {
+
+	public static void main(String[] args) {
+		System.out.println("Hello, Java Scripts!");
+	}
+
+}