001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.pool2.proxy;
018
019import java.util.NoSuchElementException;
020
021import org.apache.commons.pool2.ObjectPool;
022import org.apache.commons.pool2.UsageTracking;
023
024/**
025 * Create a new object pool where the pooled objects are wrapped in proxies
026 * allowing better control of pooled objects and in particular the prevention
027 * of the continued use of an object by a client after that client returns the
028 * object to the pool.
029 *
030 * @param <T> type of the pooled object
031 *
032 * @since 2.0
033 */
034public class ProxiedObjectPool<T> implements ObjectPool<T> {
035
036    private final ObjectPool<T> pool;
037    private final ProxySource<T> proxySource;
038
039
040    /**
041     * Create a new proxied object pool.
042     *
043     * @param pool  The object pool to wrap
044     * @param proxySource The source of the proxy objects
045     */
046    public ProxiedObjectPool(final ObjectPool<T> pool, final ProxySource<T> proxySource) {
047        this.pool = pool;
048        this.proxySource = proxySource;
049    }
050
051
052    // --------------------------------------------------- ObjectPool<T> methods
053
054    @SuppressWarnings("unchecked")
055    @Override
056    public T borrowObject() throws Exception, NoSuchElementException,
057            IllegalStateException {
058        UsageTracking<T> usageTracking = null;
059        if (pool instanceof UsageTracking) {
060            usageTracking = (UsageTracking<T>) pool;
061        }
062        final T pooledObject = pool.borrowObject();
063        final T proxy = proxySource.createProxy(pooledObject, usageTracking);
064        return proxy;
065    }
066
067
068    @Override
069    public void returnObject(final T proxy) throws Exception {
070        final T pooledObject = proxySource.resolveProxy(proxy);
071        pool.returnObject(pooledObject);
072    }
073
074
075    @Override
076    public void invalidateObject(final T proxy) throws Exception {
077        final T pooledObject = proxySource.resolveProxy(proxy);
078        pool.invalidateObject(pooledObject);
079    }
080
081
082    @Override
083    public void addObject() throws Exception, IllegalStateException,
084            UnsupportedOperationException {
085        pool.addObject();
086    }
087
088
089    @Override
090    public int getNumIdle() {
091        return pool.getNumIdle();
092    }
093
094
095    @Override
096    public int getNumActive() {
097        return pool.getNumActive();
098    }
099
100
101    @Override
102    public void clear() throws Exception, UnsupportedOperationException {
103        pool.clear();
104    }
105
106
107    @Override
108    public void close() {
109        pool.close();
110    }
111
112
113    /**
114     * @since 2.4.3
115     */
116    @Override
117    public String toString() {
118        final StringBuilder builder = new StringBuilder();
119        builder.append("ProxiedObjectPool [pool=");
120        builder.append(pool);
121        builder.append(", proxySource=");
122        builder.append(proxySource);
123        builder.append("]");
124        return builder.toString();
125    }
126}