[LANG-762] Handle or document ReflectionToStringBuilder and ToStringBuilder for collections that are not thread safe.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1199786 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 116 insertions, 0 deletions

diff --git a/src/test/java/org/apache/commons/lang3/builder/ReflectionToStringBuilderConcurrencyTest.java b/src/test/java/org/apache/commons/lang3/builder/ReflectionToStringBuilderConcurrencyTest.java
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+/*

+ * 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 junit.framework.Assert;

+

+import org.junit.Ignore;

+import org.junit.Test;

+

+/**

+ * Tests concurrent access for {@link ReflectionToStringBuilder}.

+ * <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>

+ * The tests on the non-thread-safe collections do not pass.

+ * </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 3.0.2

+ */

+public class ReflectionToStringBuilderConcurrencyTest {

+

+    static class CollectionHolder<T extends Collection<?>> {

+        T collection;

+

+        CollectionHolder(T collection) {

+            this.collection = collection;

+        }

+    }

+

+    private static final int DATA_SIZE = 100000;

+    private static final int REPEAT = 100;

+

+    @Test

+    @Ignore

+    public void testLinkedList() throws InterruptedException, ExecutionException {

+        this.testConcurrency(new CollectionHolder<List<Integer>>(new LinkedList<Integer>()));

+    }

+

+    @Test

+    @Ignore

+    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()

+        for (int i = 0; i < DATA_SIZE; i++) {

+            list.add(Integer.valueOf(i));

+        }

+        // 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++) {

+                    String s = ReflectionToStringBuilder.toString(holder);

+                    Assert.assertNotNull(s);

+                }

+                return REPEAT;

+            }

+        };

+        // Produces changes in the list

+        Callable<Integer> producer = new Callable<Integer>() {

+            public Integer call() {

+                for (int i = 0; i < DATA_SIZE; i++) {

+                    list.remove(list.get(0));

+                }

+                return REPEAT;

+            }

+        };

+        Collection<Callable<Integer>> tasks = new ArrayList<Callable<Integer>>();

+        tasks.add(consumer);

+        tasks.add(producer);

+        final List<Future<Integer>> futures = threadPool.invokeAll(tasks);

+        for (Future<Integer> future : futures) {

+            Assert.assertEquals(REPEAT, future.get().intValue());

+        }

+    }

+}