test/jdk/java/lang/Thread/JoinWithDuration.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 */

/**
 * @test
 * @summary Test Thread.join(Duration)
 * @run junit JoinWithDuration
 */

import java.time.Duration;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.LockSupport;

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;

class JoinWithDuration {
    /**
     * Test join on unstarted thread.
     */
    @Test
    void testJoinOnUnstartedThread() {
        var thread = new Thread(() -> { });
        assertThrows(IllegalThreadStateException.class,
                () -> thread.join(Duration.ofNanos(-100)));
        assertThrows(IllegalThreadStateException.class,
                () -> thread.join(Duration.ofNanos(0)));
        assertThrows(IllegalThreadStateException.class,
                () -> thread.join(Duration.ofNanos(100)));
    }

    /**
     * Test join on thread that does not terminate while waiting.
     */
    @Test
    void testJoinOnRunningThread() throws Exception {
        var thread = new Thread(LockSupport::park);
        thread.start();
        try {
            assertFalse(thread.join(Duration.ofNanos(-100)));
            assertFalse(thread.join(Duration.ofNanos(0)));
            assertFalse(thread.join(Duration.ofNanos(100)));

            // test duration of join
            long start = millisTime();
            assertFalse(thread.join(Duration.ofMillis(2000)));
            expectDuration(start, /*min*/1900, /*max*/20_000);

        } finally {
            LockSupport.unpark(thread);
            thread.join();
        }
    }

    /**
     * Test join on thread that terminates while waiting.
     */
    @Test
    void testJoinOnTerminatingThread() throws Exception {
        var thread = new Thread(() -> {
            try {
                Thread.sleep(50);
            } catch (InterruptedException e) { }
        });
        thread.start();
        assertTrue(thread.join(Duration.ofMinutes(1)));
    }

    /**
     * Test join on terminated thread.
     */
    @Test
    void testJoinOnTerminatedThread() throws Exception {
        var thread = new Thread(() -> { });
        thread.start();
        thread.join();
        assertTrue(thread.join(Duration.ofNanos(-100)));
        assertTrue(thread.join(Duration.ofNanos(0)));
        assertTrue(thread.join(Duration.ofNanos(100)));
    }

    /**
     * Test invoking join with interrupt status set.
     */
    @Test
    void testJoinWithInterruptStatusSet() throws Exception {
        var thread = new Thread(LockSupport::park);
        thread.start();
        Thread.currentThread().interrupt();
        try {
            assertThrows(InterruptedException.class,
                    () -> thread.join(Duration.ofMinutes(1)));
            assertFalse(Thread.currentThread().isInterrupted());
        } finally {
            Thread.interrupted();
            LockSupport.unpark(thread);
            thread.join();
        }
    }

    /**
     * Test interrupting join.
     */
    @Test
    void testInterruptJoin() throws Exception {
        // schedule current thread to be interrupted after 1s
        Thread targetThread = Thread.currentThread();
        Thread wakerThread = new Thread(() -> {
            try {
                Thread.sleep(1000);
                targetThread.interrupt();
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
        wakerThread.start();

        var thread = new Thread(LockSupport::park);
        thread.start();
        try {
            thread.join(Duration.ofMinutes(1));
            fail();
        } catch (InterruptedException e) {
            // interrupt status should be cleared
            assertFalse(thread.isInterrupted());
        } finally {
            LockSupport.unpark(thread);
            thread.join();
            wakerThread.join();
        }
    }

    /**
     * Test join on current thread.
     */
    @Test
    void testJoinSelf() throws Exception {
        Thread thread = Thread.currentThread();

        assertFalse(thread.join(Duration.ofNanos(-100)));
        assertFalse(thread.join(Duration.ofNanos(0)));
        assertFalse(thread.join(Duration.ofNanos(100)));

        // test duration of join
        long start = millisTime();
        assertFalse(thread.join(Duration.ofMillis(2000)));
        expectDuration(start, /*min*/1900, /*max*/20_000);
    }

    /**
     * Test join(null).
     */
    @Test
    void testJoinNull() throws Exception {
        var thread = new Thread(LockSupport::park);

        // unstarted
        assertThrows(NullPointerException.class, () -> thread.join(null));

        // started
        thread.start();
        try {
            assertThrows(NullPointerException.class, () -> thread.join(null));
        } finally {
            LockSupport.unpark(thread);
        }
        thread.join();

        // terminated
        assertThrows(NullPointerException.class, () -> thread.join(null));
    }

    /**
     * Returns the current time in milliseconds.
     */
    private static long millisTime() {
        long now = System.nanoTime();
        return TimeUnit.MILLISECONDS.convert(now, TimeUnit.NANOSECONDS);
    }

    /**
     * Check the duration of a task
     * @param start start time, in milliseconds
     * @param min minimum expected duration, in milliseconds
     * @param max maximum expected duration, in milliseconds
     * @return the duration (now - start), in milliseconds
     */
    private static void expectDuration(long start, long min, long max) {
        long duration = millisTime() - start;
        assertTrue(duration >= min,
                "Duration " + duration + "ms, expected >= " + min + "ms");
        assertTrue(duration <= max,
                "Duration " + duration + "ms, expected <= " + max + "ms");
    }

}