// concurrency/Ex3.java
// TIJ4 Chapter Concurrency, Exercise 3, page 1124
// Repeat Exercise 1 using the different types of executors shown in this section.
 
/* My solution to one of the exercises in 
* Thinking in Java 4th Edition (by Bruce Eckel).
* It compiles and runs correctly using JDK 1.6.0
* @author Greg Gordon
* @author www.greggordon.org
* May, 2009
*/

import java.util.concurrent.*;

class Ex3RunnerA implements Runnable {
	public Ex3RunnerA() {
		System.out.println("Constructing Ex3RunnerA");
	}
	public void run() {
		for(int i = 0; i < 3; i++) {
			System.out.println("Hi from Ex3RunnerA");		
			Thread.yield();
		}
		System.out.println("Ex3RunnerA task complete.");
		return;				
	}
}

class Ex3RunnerB implements Runnable {
	public Ex3RunnerB() {
		System.out.println("Constructing Ex3RunnerB");
	}
	public void run() {
		for(int i = 0; i < 3; i++) {
			System.out.println("Hi from Ex3RunnerB");		
			Thread.yield();
		}
		System.out.println("Ex3RunnerB task complete.");
		return;
	}
}

class Ex3RunnerC implements Runnable {
	public Ex3RunnerC() {
		System.out.println("Constructing Ex3RunnerC");
	}
	public void run() {
		for(int i = 0; i < 3; i++) {
			System.out.println("Hi from Ex3RunnerC");		
			Thread.yield();
		}
		System.out.println("Ex3RunnerC task complete.");
		return;	
	}
}

public class Ex3 {
	public static void main(String[] args) {
		ExecutorService exec1 = Executors.newCachedThreadPool();
		exec1.execute(new Ex3RunnerA());
		exec1.execute(new Ex3RunnerB());
		exec1.execute(new Ex3RunnerC());
		exec1.shutdown();
		ExecutorService exec2 = Executors.newFixedThreadPool(3);
		exec2.execute(new Ex3RunnerA());
		exec2.execute(new Ex3RunnerB());
		exec2.execute(new Ex3RunnerC());
		exec2.shutdown();
		ExecutorService exec3 = Executors.newSingleThreadExecutor();
		exec3.execute(new Ex3RunnerA());
		exec3.execute(new Ex3RunnerB());
		exec3.execute(new Ex3RunnerC());
		exec3.shutdown();
	}
}