| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.beam.sdk.testing; |
| |
| import static java.util.stream.Collectors.joining; |
| import static java.util.stream.Collectors.toList; |
| import static org.junit.Assert.fail; |
| |
| import java.lang.reflect.Field; |
| import java.util.List; |
| import java.util.stream.Stream; |
| import org.junit.rules.TestRule; |
| import org.junit.runner.Description; |
| import org.junit.runners.model.Statement; |
| |
| /** |
| * Tracks the threads created during a test method execution (or class using @ClassRule) and fails |
| * if some still exists after the test method execution. |
| */ |
| public class ThreadLeakTracker implements TestRule { |
| private final Field groupField; |
| |
| public ThreadLeakTracker() { |
| try { |
| groupField = Thread.class.getDeclaredField("group"); |
| if (!groupField.isAccessible()) { |
| groupField.setAccessible(true); |
| } |
| } catch (final NoSuchFieldException e) { |
| throw new IllegalStateException(e); |
| } |
| } |
| |
| @Override |
| public Statement apply(final Statement base, final Description description) { |
| return new Statement() { |
| @Override |
| public void evaluate() throws Throwable { |
| final Thread thread = Thread.currentThread(); |
| final ThreadGroup threadGroup = thread.getThreadGroup(); |
| final ThreadGroup testGroup = new ThreadGroup(threadGroup, Long.toString(thread.getId())); |
| groupField.set(thread, testGroup); |
| try { |
| base.evaluate(); |
| } finally { |
| groupField.set(thread, threadGroup); |
| final Thread[] threads = listThreads(); |
| final List<Thread> leaked = |
| Stream.of(threads).filter(t -> t.getThreadGroup() == testGroup).collect(toList()); |
| if (!leaked.isEmpty()) { |
| fail( |
| "Some threads leaked: " |
| + leaked.stream().map(Thread::getName).collect(joining("\n- ", "\n- ", ""))); |
| } |
| } |
| } |
| }; |
| } |
| |
| private Thread[] listThreads() { |
| final int count = Thread.activeCount(); |
| final Thread[] threads = new Thread[Math.max(count * 2, 16)]; |
| final int threadCount = Thread.enumerate(threads); |
| final Thread[] array = new Thread[threadCount]; |
| System.arraycopy(threads, 0, array, 0, threadCount); |
| return array; |
| } |
| } |