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     * Constructs 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    @Override
052    public void addObject() throws Exception, IllegalStateException,
053            UnsupportedOperationException {
054        pool.addObject();
055    }
056
057
058    @SuppressWarnings("unchecked")
059    @Override
060    public T borrowObject() throws Exception, NoSuchElementException,
061            IllegalStateException {
062        UsageTracking<T> usageTracking = null;
063        if (pool instanceof UsageTracking) {
064            usageTracking = (UsageTracking<T>) pool;
065        }
066        return proxySource.createProxy(pool.borrowObject(), usageTracking);
067    }
068
069
070    @Override
071    public void clear() throws Exception, UnsupportedOperationException {
072        pool.clear();
073    }
074
075
076    @Override
077    public void close() {
078        pool.close();
079    }
080
081
082    @Override
083    public int getNumActive() {
084        return pool.getNumActive();
085    }
086
087
088    @Override
089    public int getNumIdle() {
090        return pool.getNumIdle();
091    }
092
093
094    @Override
095    public void invalidateObject(final T proxy) throws Exception {
096        pool.invalidateObject(proxySource.resolveProxy(proxy));
097    }
098
099
100    @Override
101    public void returnObject(final T proxy) throws Exception {
102        pool.returnObject(proxySource.resolveProxy(proxy));
103    }
104
105    /**
106     * @since 2.4.3
107     */
108    @Override
109    public String toString() {
110        final StringBuilder builder = new StringBuilder();
111        builder.append("ProxiedObjectPool [pool=");
112        builder.append(pool);
113        builder.append(", proxySource=");
114        builder.append(proxySource);
115        builder.append("]");
116        return builder.toString();
117    }
118}