    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;
    018
    019/**
    020 * A base implementation of <code>KeyedPooledObjectFactory</code>.
    021 * <p>
    022 * All operations defined here are essentially no-op's.
    023 * </p>
    024 * This class is immutable, and therefore thread-safe.
    025 *
    026 * @see KeyedPooledObjectFactory
    027 *
    028 * @param <K> The type of keys managed by this factory.
    029 * @param <V> Type of element managed by this factory.
    030 *
    031 * @since 2.0
    032 */
    033public abstract class BaseKeyedPooledObjectFactory<K, V> extends BaseObject
    034        implements KeyedPooledObjectFactory<K, V> {
    035
    036    /**
    037     * Create an instance that can be served by the pool.
    038     *
    039     * @param key the key used when constructing the object
    040     * @return an instance that can be served by the pool
    041     *
    042     * @throws Exception if there is a problem creating a new instance,
    043     *    this will be propagated to the code requesting an object.
    044     */
    045    public abstract V create(K key)
    046        throws Exception;
    047
    048    /**
    049     * Wrap the provided instance with an implementation of
    050     * {@link PooledObject}.
    051     *
    052     * @param value the instance to wrap
    053     *
    054     * @return The provided instance, wrapped by a {@link PooledObject}
    055     */
    056    public abstract PooledObject<V> wrap(V value);
    057
    058    @Override
    059    public PooledObject<V> makeObject(final K key) throws Exception {
    060        return wrap(create(key));
    061    }
    062
    063    /**
    064     * Destroy an instance no longer needed by the pool.
    065     * <p>
    066     * The default implementation is a no-op.
    067     * </p>
    068     *
    069     * @param key the key used when selecting the instance
    070     * @param p a {@code PooledObject} wrapping the instance to be destroyed
    071     */
    072    @Override
    073    public void destroyObject(final K key, final PooledObject<V> p)
    074        throws Exception {
    075        // The default implementation is a no-op.
    076    }
    077
    078    /**
    079     * Ensures that the instance is safe to be returned by the pool.
    080     * <p>
    081     * The default implementation always returns {@code true}.
    082     * </p>
    083     *
    084     * @param key the key used when selecting the object
    085     * @param p a {@code PooledObject} wrapping the instance to be validated
    086     * @return always <code>true</code> in the default implementation
    087     */
    088    @Override
    089    public boolean validateObject(final K key, final PooledObject<V> p) {
    090        return true;
    091    }
    092
    093    /**
    094     * Reinitialize an instance to be returned by the pool.
    095     * <p>
    096     * The default implementation is a no-op.
    097     * </p>
    098     *
    099     * @param key the key used when selecting the object
    100     * @param p a {@code PooledObject} wrapping the instance to be activated
    101     */
    102    @Override
    103    public void activateObject(final K key, final PooledObject<V> p)
    104        throws Exception {
    105        // The default implementation is a no-op.
    106    }
    107
    108    /**
    109     * Uninitialize an instance to be returned to the idle object pool.
    110     * <p>
    111     * The default implementation is a no-op.
    112     * </p>
    113     *
    114     * @param key the key used when selecting the object
    115     * @param p a {@code PooledObject} wrapping the instance to be passivated
    116     */
    117    @Override
    118    public void passivateObject(final K key, final PooledObject<V> p)
    119        throws Exception {
    120        // The default implementation is a no-op.
    121    }
    122}