69 lines
2.2 KiB
Java
69 lines
2.2 KiB
Java
import java.util.List;
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import java.util.concurrent.ExecutionException;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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import java.util.concurrent.Future;
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import java.util.concurrent.TimeUnit;
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public class SimpleExecutorCompletionServiceTester extends Concurrent<Integer> {
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private static final int N_TASKS_PER_TESTER = 10;
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private static final ExecutorService ecs = Executors.newCachedThreadPool();
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private static final SimpleExecutorCompletionService<Integer> secs =
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new SimpleExecutorCompletionService<>(ecs);
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public SimpleExecutorCompletionServiceTester(Integer[] args) {
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super(args);
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}
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private static int sleepAndReturnTime(int sleepTimeMs) throws InterruptedException {
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Thread.sleep(sleepTimeMs);
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return sleepTimeMs;
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}
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public static void main(String[] args) {
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new SimpleExecutorCompletionServiceTester(new Integer[]{1, 2, 3, 4, 5}).run();
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List<Runnable> unstartedTasks = ecs.shutdownNow();
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if (!unstartedTasks.isEmpty())
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System.out.println("Still some unstarted tasks left after end of all tester threads!?");
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try {
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ecs.awaitTermination(1, TimeUnit.SECONDS);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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}
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@Override
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protected void perform(Integer testerNr) {
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for (int i = 0; i < N_TASKS_PER_TESTER; ++i) {
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secs.submit(() -> sleepAndReturnTime(10+10*(int)(Math.random()*10)));
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// Note that submit's result is ignored here
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}
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for (int i = 0; i < N_TASKS_PER_TESTER; ++i) {
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Future<Integer> fut = null;
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do {
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fut = secs.poll();
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if (fut == null)
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try {
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// No finished task right now => wait a bit (but less than the minimal task duration!)
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// before polling again
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Thread.sleep((long) (Math.random()*5));
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} catch (InterruptedException e) {
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// Nothing to do here: Sleep time is still random even if interrupted
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}
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} while (fut == null);
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try {
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System.out.println("Tester " + testerNr + " received result " + fut.get());
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} catch (InterruptedException | ExecutionException e) {
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e.printStackTrace();
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return;
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}
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}
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System.out.println("Tester " + testerNr + " ends.");
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}
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}
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