FutureCancelTest1.java

package futurecanceltest1;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class FutureCancelTest1 {

    private static final int task_size = 3; // 起動するタスク数
    private static final boolean mayInterruptIfRunning = true; // cancelメソッドに渡す引数

    public static void main(String[] args) throws InterruptedException {
        ExecutorService executor = Executors.newFixedThreadPool(task_size);
        Future[] futures = new Future[task_size];

        // タスクを送信
        for (int i = 0; i < task_size; i++)
            futures[i] = executor.submit(new TestRunnable(i));

        // executorが動きっぱなしになってしまうのを回避するためにshutdown
        executor.shutdown();

        // 1秒待機
        Thread.sleep(1000);

        // 現在のタスクの状態を出力
        for (int i = 0; i < task_size; i++) {
            Future f = futures[i];
            System.out.printf("index: %d, isCancelled: %b, isDone: %b\n", i, f.isCancelled(), f.isDone());
        }

        // タスクをcancelして状態を出力
        for (int i = 0; i < task_size; i++) {
            Future f = futures[i];
            System.out.printf("index: %d, cancel: %b, isCancelled: %b, isDone: %b\n", i, f.cancel(mayInterruptIfRunning), f.isCancelled(), f.isDone());
        }
    }
}

class TestRunnable implements Runnable {

    private final int index;

    public TestRunnable(int index) {
        this.index = index;
    }

    @Override
    public void run() {
        try {
            System.out.printf("index: %d, message: start\n", index);
            Thread.sleep(2000); // 2秒間停止
            System.out.printf("index: %d, message: end\n", index);
        } catch (InterruptedException ex) {
            System.out.printf("index: %d, message: InterruptedException\n", index);
        }
    }
}

FutureCancelTest2.java

package futurecanceltest2;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class FutureCancelTest2 {

    private static final int task_size = 3; // 起動するタスク数
    private static final boolean mayInterruptIfRunning = true; // cancelメソッドに渡す引数

    public static void main(String[] args) throws InterruptedException {
        ExecutorService executor = Executors.newFixedThreadPool(task_size);
        Future[] futures = new Future[task_size];

        // タスクを送信
        for (int i = 0; i < task_size; i++)
            futures[i] = executor.submit(new TestRunnable(i));

        // executorが動きっぱなしになってしまうのを回避するためにshutdown
        executor.shutdown();

        // 1秒待機
        Thread.sleep(1000);

        // 現在のタスクの状態を出力
        for (int i = 0; i < task_size; i++) {
            Future f = futures[i];
            System.out.printf("index: %d, isCancelled: %b, isDone: %b\n", i, f.isCancelled(), f.isDone());
        }

        
        // タスクをcancelして状態を出力
        for (int i = 0; i < task_size; i++) {
            Future f = futures[i];
            try {
                f.get();
            } catch (ExecutionException ex) {
                System.out.printf("index: %d, message: ExecutionException\n", i);
            }
            System.out.printf("index: %d, cancel: %b, isCancelled: %b, isDone: %b\n", i, f.cancel(mayInterruptIfRunning), f.isCancelled(), f.isDone());
        }
    }
}

class TestRunnable implements Runnable {

    private final int index;

    public TestRunnable(int index) {
        this.index = index;
    }

    @Override
    public void run() {
        try {
            System.out.printf("index: %d, message: start\n", index);
            Thread.sleep(2000); // 2秒間停止
            System.out.printf("index: %d, message: end\n", index);
        } catch (InterruptedException ex) {
            System.out.printf("index: %d, message: InterruptedException\n", index);
        }
    }
}