    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}