LUCENE-3693: Add a testing implementation for DocumentsWriterPerThreadPool

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1232023 13f79535-47bb-0310-9956-ffa450edef68

lucene/src/test-framework/java/org/apache/lucene/index/RandomDocumentsWriterPerThreadPool.java

@@ -0,0 +1,91 @@
+package org.apache.lucene.index;
+
+/**
+ * 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.
+ */
+import java.util.Random;
+
+/**
+ * 
+ * A {@link DocumentsWriterPerThreadPool} that selects thread states at random.
+ * 
+ * @lucene.internal
+ * @lucene.experimental
+ */
+public class RandomDocumentsWriterPerThreadPool extends
+    DocumentsWriterPerThreadPool {
+  private final ThreadState[] states;
+  private final Random random;
+  private final int maxRetry;
+
+  public RandomDocumentsWriterPerThreadPool(int maxNumPerThreads, Random random) {
+    super(maxNumPerThreads);
+    assert getMaxThreadStates() >= 1;
+    states = new ThreadState[maxNumPerThreads];
+    this.random = new Random(random.nextLong());
+    this.maxRetry = 1 + random.nextInt(10);
+  }
+
+  @Override
+  public ThreadState getAndLock(Thread requestingThread,
+      DocumentsWriter documentsWriter) {
+    ThreadState threadState = null;
+    if (getActiveThreadState() == 0) {
+      synchronized (this) {
+        if (getActiveThreadState() == 0) {
+          threadState = states[0] = newThreadState();
+          return threadState;
+        }
+      }
+    }
+    assert getActiveThreadState() > 0;
+    for (int i = 0; i < maxRetry; i++) {
+      int ord = random.nextInt(getActiveThreadState());
+      synchronized (this) {
+        threadState = states[ord];
+        assert threadState != null;
+      }
+
+      if (threadState.tryLock()) {
+        return threadState;
+      }
+      if (random.nextInt(20) == 0) {
+        break;
+      }
+    }
+    /*
+     * only try to create a new threadstate if we can not lock the randomly
+     * selected state. this is important since some tests rely on a single
+     * threadstate in the single threaded case. Eventually it would be nice if
+     * we would not have this limitation but for now we just make sure we only
+     * allocate one threadstate if indexing is single threaded
+     */
+
+    synchronized (this) {
+      ThreadState newThreadState = newThreadState();
+      if (newThreadState != null) { // did we get a new state?
+        threadState = states[getActiveThreadState() - 1] = newThreadState;
+        assert threadState.isHeldByCurrentThread();
+        return threadState;
+      }
+      // if no new state is available lock the random one
+    }
+    assert threadState != null;
+    threadState.lock();
+    return threadState;
+  }
+
+}

lucene/src/test-framework/java/org/apache/lucene/util/LuceneTestCase.java

@@ -914,12 +914,14 @@ public abstract class LuceneTestCase extends Assert {
       }
     }
     if (r.nextBoolean()) {
+      int maxNumThreadStates = rarely(r) ? _TestUtil.nextInt(r, 5, 20) // crazy value
+          : _TestUtil.nextInt(r, 1, 4); // reasonable value
       if (rarely(r)) {
-        // crazy value
-        c.setIndexerThreadPool(new ThreadAffinityDocumentsWriterThreadPool(_TestUtil.nextInt(r, 5, 20)));
+        // random thread pool
+        c.setIndexerThreadPool(new RandomDocumentsWriterPerThreadPool(maxNumThreadStates, r));
       } else {
-        // reasonable value
-        c.setIndexerThreadPool(new ThreadAffinityDocumentsWriterThreadPool(_TestUtil.nextInt(r, 1, 4)));
+        // random thread pool
+        c.setIndexerThreadPool(new ThreadAffinityDocumentsWriterThreadPool(maxNumThreadStates));
       }
     }