/*
* Copyright 2002-2007 the original author or authors.
*
* Licensed 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.springmodules.lucene.index.factory.concurrent;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import org.springmodules.lucene.index.LuceneIndexAccessException;
import org.springmodules.lucene.index.factory.LuceneIndexReader;
import org.springmodules.lucene.index.factory.LuceneIndexWriter;
import edu.emory.mathcs.backport.java.util.concurrent.locks.ReentrantLock;
/**
* Concurrent {@link org.springmodules.lucene.index.factory.IndexFactory}
* based on lock.
*
* Wrap the target {@link org.springmodules.lucene.index.factory.IndexFactory}
* in order to manage the acquisition and the release of locks.
*
* The lock is acquired when an index reader or writer is getting (see {@link #getIndexReader()}
* and {@link #getIndexWriter()} and is released by the close calls of these
* wrapped instances.
*
* @author Thierry Templier
*/
public class LockIndexFactory extends AbstractConcurrentIndexFactory {
private static final String CLOSE_METHOD_NAME = "close";
private ReentrantLock lock;
/**
* @see org.springmodules.lucene.index.factory.concurrent.ConcurrentIndexFactory#destroyConcurrentResources()
*/
public void destroyConcurrentResources() throws Exception {
lock = null;
}
/**
* @see org.springmodules.lucene.index.factory.concurrent.ConcurrentIndexFactory#initConcurrentResources()
*/
public void initConcurrentResources() throws Exception {
lock = new ReentrantLock();
}
/**
* Implement the acquisition of a lock using the ReentrantLock class.
*
* @throws InterruptedException
* @see edu.emory.mathcs.backport.java.util.concurrent.locks.ReentrantLock#lock()
*/
private void acquireLock() throws InterruptedException {
lock.lock();
}
/**
* Implement the release of a lock using the ReentrantLock class.
*
* @throws InterruptedException
* @see edu.emory.mathcs.backport.java.util.concurrent.locks.ReentrantLock#unlock()
*/
private void releaseLock() {
lock.unlock();
}
/**
* Acquire a lock and return a proxy on a target IndexReader. This proxy
* will be able to manage the release of the lock on close calls.
*
* @return a proxy on a target IndexReader
*/
public LuceneIndexReader getIndexReader() {
try {
acquireLock();
LuceneIndexReader indexReader = getTargetIndexFactory().getIndexReader();
return (LuceneIndexReader) Proxy.newProxyInstance(
LuceneIndexReader.class.getClassLoader(),
new Class[] {LuceneIndexReader.class},
new LockLuceneIndexReaderInvocationHandler(indexReader));
} catch(InterruptedException ex) {
releaseLock();
throw new LuceneIndexAccessException("Unable to manage lock", ex);
}
}
/**
* Acquire a lock and return a proxy on a target IndexWriter. This proxy
* will be able to manage the release of the lock on close calls.
*
* @return a proxy on a target IndexWriter
*/
public LuceneIndexWriter getIndexWriter() {
try {
acquireLock();
LuceneIndexWriter indexWriter = getTargetIndexFactory().getIndexWriter();
return (LuceneIndexWriter) Proxy.newProxyInstance(
LuceneIndexWriter.class.getClassLoader(),
new Class[] {LuceneIndexWriter.class},
new LockLuceneIndexWriterInvocationHandler(indexWriter));
} catch(InterruptedException ex) {
releaseLock();
throw new LuceneIndexAccessException("Unable to manage lock", ex);
}
}
/**
* Invocation handler that releases locks after close calls of IndexReader
*/
private class LockLuceneIndexReaderInvocationHandler implements InvocationHandler {
private final LuceneIndexReader indexReader;
public LockLuceneIndexReaderInvocationHandler(LuceneIndexReader indexReader) {
this.indexReader = indexReader;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Object ret = method.invoke(indexReader, args);
if( CLOSE_METHOD_NAME.equals(method.getName()) ) {
releaseLock();
}
return ret;
}
}
/**
* Invocation handler that releases locks after close calls of IndexWriter
*/
private class LockLuceneIndexWriterInvocationHandler implements InvocationHandler {
private final LuceneIndexWriter indexWriter;
public LockLuceneIndexWriterInvocationHandler(LuceneIndexWriter indexWriter) {
this.indexWriter = indexWriter;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Object ret = method.invoke(indexWriter, args);
if( CLOSE_METHOD_NAME.equals(method.getName()) ) {
releaseLock();
}
return ret;
}
}
}