1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache license, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the license for the specific language governing permissions and
15 * limitations under the license.
16 */
17
18 package org.apache.commons.logging;
19
20 import java.io.Closeable;
21 import java.io.IOException;
22 import java.io.OutputStream;
23 import java.util.concurrent.CountDownLatch;
24 import java.util.concurrent.TimeUnit;
25 import java.util.concurrent.atomic.AtomicBoolean;
26
27 // after: https://github.com/apache/logging-log4j2/blob/c47e98423b461731f7791fcb9ea1079cd451f365/log4j-core/src/test/java/org/apache/logging/log4j/core/GarbageCollectionHelper.java
28 public final class GarbageCollectionHelper implements Closeable, Runnable {
29 final class GcTask implements Runnable {
30 @Override
31 public void run() {
32 try {
33 while (running.get()) {
34 // Allocate data to help suggest a GC
35 try {
36 // 1mb of heap
37 final byte[] buf = new byte[1024 * 1024];
38 SINK.write(buf);
39 } catch (final IOException ignored) {
40 }
41 // May no-op depending on the JVM configuration
42 System.gc();
43 }
44 } finally {
45 latch.countDown();
46 }
47 }
48 }
49 private static final OutputStream SINK = new OutputStream() {
50 @Override
51 public void write(final byte[] b) {
52 }
53
54 @Override
55 public void write(final byte[] b, final int off, final int len) {
56 }
57
58 @Override
59 public void write(final int b) {
60 }
61 };
62 private final AtomicBoolean running = new AtomicBoolean();
63 private final CountDownLatch latch = new CountDownLatch(1);
64
65 private final Thread gcThread = new Thread(new GcTask());
66
67 @Override
68 public void close() {
69 running.set(false);
70 try {
71 junit.framework.TestCase.assertTrue("GarbageCollectionHelper did not shut down cleanly",
72 latch.await(10, TimeUnit.SECONDS));
73 } catch (final InterruptedException e) {
74 throw new RuntimeException(e);
75 }
76 }
77
78 @Override
79 public void run() {
80 if (running.compareAndSet(false, true)) {
81 gcThread.start();
82 }
83 }
84 }
85