137 lines
5.0 KiB
Java
137 lines
5.0 KiB
Java
/*
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* Copyright (c) 2006, 2023, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* @test
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* @bug 6399443 8302899
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* @summary Test that Executors.newSingleThreadExecutor wraps an ExecutorService that
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* automatically shuts down and terminates when the wrapper is GC'ed
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* @modules java.base/java.util.concurrent:+open
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* @run junit AutoShutdown
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*/
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import java.lang.reflect.Field;
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import java.time.Duration;
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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.TimeUnit;
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import java.util.concurrent.atomic.AtomicInteger;
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import java.util.function.Supplier;
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import java.util.stream.Stream;
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import java.util.stream.IntStream;
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import org.junit.jupiter.api.Test;
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import org.junit.jupiter.params.ParameterizedTest;
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import org.junit.jupiter.params.provider.MethodSource;
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import org.junit.jupiter.params.provider.Arguments;
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import static org.junit.jupiter.api.Assertions.*;
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class AutoShutdown {
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private static Stream<Supplier<ExecutorService>> executors() {
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return Stream.of(
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() -> Executors.newSingleThreadExecutor(),
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() -> Executors.newSingleThreadExecutor(Executors.defaultThreadFactory())
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);
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}
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private static Stream<Arguments> executorAndQueuedTaskCounts() {
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int[] queuedTaskCounts = { 0, 1, 2 };
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return executors().flatMap(s -> IntStream.of(queuedTaskCounts)
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.mapToObj(i -> Arguments.of(s, i)));
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}
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/**
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* SingleThreadExecutor with no worker threads.
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*/
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@ParameterizedTest
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@MethodSource("executors")
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void testNoWorker(Supplier<ExecutorService> supplier) throws Exception {
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ExecutorService executor = supplier.get();
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ExecutorService delegate = getDelegate(executor);
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executor = null;
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gcAndAwaitTermination(delegate);
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}
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/**
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* SingleThreadExecutor with an idle worker thread.
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*/
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@ParameterizedTest
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@MethodSource("executors")
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void testIdleWorker(Supplier<ExecutorService> supplier) throws Exception {
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ExecutorService executor = supplier.get();
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// submit a task to get a worker to start
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executor.submit(() -> null).get();
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ExecutorService delegate = getDelegate(executor);
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executor = null;
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gcAndAwaitTermination(delegate);
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}
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/**
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* SingleThreadExecutor with an active worker and queued tasks.
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*/
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@ParameterizedTest
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@MethodSource("executorAndQueuedTaskCounts")
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void testActiveWorker(Supplier<ExecutorService> supplier,int queuedTaskCount) throws Exception {
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ExecutorService executor = supplier.get();
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// the worker will execute one task, the other tasks will be queued
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int ntasks = 1 + queuedTaskCount;
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AtomicInteger completedTaskCount = new AtomicInteger();
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for (int i = 0; i < ntasks; i++) {
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executor.submit(() -> {
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Thread.sleep(Duration.ofMillis(500));
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completedTaskCount.incrementAndGet();
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return null;
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});
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}
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ExecutorService delegate = getDelegate(executor);
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executor = null;
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gcAndAwaitTermination(delegate);
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assertEquals(ntasks, completedTaskCount.get());
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}
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/**
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* Returns the delegate for the given ExecutorService. The given ExecutorService
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* must be a Executors$DelegatedExecutorService.
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*/
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private ExecutorService getDelegate(ExecutorService executor) throws Exception {
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Field eField = Class.forName("java.util.concurrent.Executors$DelegatedExecutorService")
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.getDeclaredField("e");
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eField.setAccessible(true);
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return (ExecutorService) eField.get(executor);
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}
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/**
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* Invokes System.gc and waits for the given ExecutorService to terminate.
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*/
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private void gcAndAwaitTermination(ExecutorService executor) throws Exception {
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System.err.println(executor);
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boolean terminated = false;
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while (!terminated) {
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System.gc();
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terminated = executor.awaitTermination(100, TimeUnit.MILLISECONDS);
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}
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}
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}
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