/*
* 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.commons.lang3.builder;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import org.junit.Test;
/**
* Tests concurrent access for the default {@link ToStringStyle}.
* <p>
* The {@link ToStringStyle} class includes a registry to avoid infinite loops for objects with circular references. We
* want to make sure that we do not get concurrency exceptions accessing this registry.
* </p>
* <p>
* This test passes but only tests one aspect of the issue.
* </p>
*
* @see <a href="https://issues.apache.org/jira/browse/LANG-762">[LANG-762] Handle or document ReflectionToStringBuilder
* and ToStringBuilder for collections that are not thread safe</a>
* @since 3.1
* @version $Id: ToStringStyleConcurrencyTest.java 1199816 2011-11-09 16:11:34Z bayard $
*/
public class ToStringStyleConcurrencyTest {
static class CollectionHolder<T extends Collection<?>> {
T collection;
CollectionHolder(T collection) {
this.collection = collection;
}
}
private static final List<Integer> LIST;
private static final int LIST_SIZE = 100000;
private static final int REPEAT = 100;
static {
LIST = new ArrayList<Integer>(LIST_SIZE);
for (int i = 0; i < LIST_SIZE; i++) {
LIST.add(Integer.valueOf(i));
}
}
@Test
public void testLinkedList() throws InterruptedException, ExecutionException {
this.testConcurrency(new CollectionHolder<List<Integer>>(new LinkedList<Integer>()));
}
@Test
public void testArrayList() throws InterruptedException, ExecutionException {
this.testConcurrency(new CollectionHolder<List<Integer>>(new ArrayList<Integer>()));
}
@Test
public void testCopyOnWriteArrayList() throws InterruptedException, ExecutionException {
this.testConcurrency(new CollectionHolder<List<Integer>>(new CopyOnWriteArrayList<Integer>()));
}
private void testConcurrency(final CollectionHolder<List<Integer>> holder) throws InterruptedException,
ExecutionException {
final List<Integer> list = holder.collection;
// make a big array that takes a long time to toString()
list.addAll(LIST);
// Create a thread pool with two threads to cause the most contention on the underlying resource.
final ExecutorService threadPool = Executors.newFixedThreadPool(2);
// Consumes toStrings
Callable<Integer> consumer = new Callable<Integer>() {
public Integer call() {
for (int i = 0; i < REPEAT; i++) {
// Calls ToStringStyle
new ToStringBuilder(holder).append(holder.collection);
}
return REPEAT;
}
};
Collection<Callable<Integer>> tasks = new ArrayList<Callable<Integer>>();
tasks.add(consumer);
tasks.add(consumer);
final List<Future<Integer>> futures = threadPool.invokeAll(tasks);
for (Future<Integer> future : futures) {
future.get();
}
}
}