import java.util.concurrent.Callable;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

public class ExecutorTest7_2 {
    public ExecutorTest7_2() {
        ExecutorService e = Executors.newCachedThreadPool();

        System.out.println("Initial Thread Pool:");
        ConcurrentUtils.listThread();
        
        e.execute(new RunnableTask("Task0"));

        for (int i = 0; i <= 80; i+=20) {
            System.out.println("\n" + i + " seconds:");
            ConcurrentUtils.listThread();
            try {
                TimeUnit.SECONDS.sleep(20);
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
        }

        e.shutdown();

        System.out.println("Terminating Threads:");
        ConcurrentUtils.listThread();
    }

    class RunnableTask implements Runnable {
        private String name;

        public RunnableTask(String name) {
            this.name = name;
        }

        public void run() {
            System.out.println(name + " Starts.");

            try {
                Thread.sleep(2000L);
            } catch (InterruptedException ex) {
                System.out.println(name + " is Canceled");
                return;
            }
            System.out.println(name + " is Done.");
        }
    }

    public static void main(String[] args) {
        new ExecutorTest7_2();
    }
}