test/jdk/java/nio/channels/Selector/LotsOfInterrupts.java

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/*
 * @test id=platform
 * @bug 8323782
 * @summary Stress test Thread.interrupt on a target Thread doing a selection operation
 * @run main LotsOfInterrupts 200000
 */

/*
 * @test id=virtual
 * @run main/othervm -DthreadFactory=virtual LotsOfInterrupts 200000
 */

import java.nio.channels.Selector;
import java.time.Instant;
import java.util.concurrent.Phaser;
import java.util.concurrent.ThreadFactory;

public class LotsOfInterrupts {

    public static void main(String[] args) throws Exception {
        int iterations;
        if (args.length > 0) {
            iterations = Integer.parseInt(args[0]);
        } else {
            iterations = 500_000;
        }

        ThreadFactory factory;
        String value = System.getProperty("threadFactory");
        if ("virtual".equals(value)) {
            factory = Thread.ofVirtual().factory();
        } else {
            factory = Thread.ofPlatform().factory();
        }

        var phaser = new Phaser(2);

        Thread thread = factory.newThread(() -> {
            try (Selector sel = Selector.open()) {
                for (int i = 0; i < iterations; i++) {
                    phaser.arriveAndAwaitAdvance();
                    sel.select();

                    // clear interrupt status and consume wakeup
                    Thread.interrupted();
                    sel.selectNow();
                }
            } catch (Throwable ex) {
                ex.printStackTrace();
            }
        });
        thread.start();

        long lastTimestamp = System.currentTimeMillis();
        for (int i = 0; i < iterations; i++) {
            phaser.arriveAndAwaitAdvance();
            thread.interrupt();

            long currentTime = System.currentTimeMillis();
            if ((currentTime - lastTimestamp) > 500) {
                System.out.format("%s %d iterations remaining ...%n", Instant.now(), (iterations - i));
                lastTimestamp = currentTime;
            }
        }

        thread.join();
    }
}