pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / store / VerifyingLockFactory.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/store/VerifyingLockFactory.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/store/VerifyingLockFactory.java
new file mode 100644 (file)
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+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/store/VerifyingLockFactory.java
@@ -0,0 +1,125 @@
+package org.apache.lucene.store;
+
+/**
+ * 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.net.Socket;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * A {@link LockFactory} that wraps another {@link
+ * LockFactory} and verifies that each lock obtain/release
+ * is "correct" (never results in two processes holding the
+ * lock at the same time).  It does this by contacting an
+ * external server ({@link LockVerifyServer}) to assert that
+ * at most one process holds the lock at a time.  To use
+ * this, you should also run {@link LockVerifyServer} on the
+ * host & port matching what you pass to the constructor.
+ *
+ * @see LockVerifyServer
+ * @see LockStressTest
+ */
+
+public class VerifyingLockFactory extends LockFactory {
+
+  LockFactory lf;
+  byte id;
+  String host;
+  int port;
+
+  private class CheckedLock extends Lock {
+    private Lock lock;
+
+    public CheckedLock(Lock lock) {
+      this.lock = lock;
+    }
+
+    private void verify(byte message) {
+      try {
+        Socket s = new Socket(host, port);
+        OutputStream out = s.getOutputStream();
+        out.write(id);
+        out.write(message);
+        InputStream in = s.getInputStream();
+        int result = in.read();
+        in.close();
+        out.close();
+        s.close();
+        if (result != 0)
+          throw new RuntimeException("lock was double acquired");
+      } catch (Exception e) {
+        throw new RuntimeException(e);
+      }
+    }
+
+    @Override
+    public synchronized boolean obtain(long lockWaitTimeout)
+      throws LockObtainFailedException, IOException {
+      boolean obtained = lock.obtain(lockWaitTimeout);
+      if (obtained)
+        verify((byte) 1);
+      return obtained;
+    }
+
+    @Override
+    public synchronized boolean obtain()
+      throws LockObtainFailedException, IOException {
+      return lock.obtain();
+    }
+
+    @Override
+    public synchronized boolean isLocked() throws IOException {
+      return lock.isLocked();
+    }
+
+    @Override
+    public synchronized void release() throws IOException {
+      if (isLocked()) {
+        verify((byte) 0);
+        lock.release();
+      }
+    }
+  }
+
+  /**
+   * @param id should be a unique id across all clients
+   * @param lf the LockFactory that we are testing
+   * @param host host or IP where {@link LockVerifyServer}
+            is running
+   * @param port the port {@link LockVerifyServer} is
+            listening on
+  */
+  public VerifyingLockFactory(byte id, LockFactory lf, String host, int port) throws IOException {
+    this.id = id;
+    this.lf = lf;
+    this.host = host;
+    this.port = port;
+  }
+
+  @Override
+  public synchronized Lock makeLock(String lockName) {
+    return new CheckedLock(lf.makeLock(lockName));
+  }
+
+  @Override
+  public synchronized void clearLock(String lockName)
+    throws IOException {
+    lf.clearLock(lockName);
+  }
+}