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
019import java.util.Objects;
020
021/**
022 * A base implementation of {@code PoolableObjectFactory}.
023 * <p>
024 * All operations defined here are essentially no-op's.
025 * <p>
026 * This class is immutable, and therefore thread-safe
027 *
028 * @param <T> Type of element managed in this factory.
029 *
030 * @see PooledObjectFactory
031 * @see BaseKeyedPooledObjectFactory
032 *
033 * @since 2.0
034 */
035public abstract class BasePooledObjectFactory<T> extends BaseObject implements PooledObjectFactory<T> {
036
037    /**
038     *  No-op.
039     *
040     *  @param p ignored
041     */
042    @Override
043    public void activateObject(final PooledObject<T> p) throws Exception {
044        // The default implementation is a no-op.
045    }
046
047    /**
048     * Creates an object instance, to be wrapped in a {@link PooledObject}.
049     * <p>This method <strong>must</strong> support concurrent, multi-threaded
050     * invocation.</p>
051     *
052     * @return an instance to be served by the pool, not null.
053     *
054     * @throws Exception if there is a problem creating a new instance,
055     *    this will be propagated to the code requesting an object.
056     */
057    public abstract T create() throws Exception;
058
059    /**
060     *  No-op.
061     *
062     *  @param p ignored
063     */
064    @Override
065    public void destroyObject(final PooledObject<T> p) throws Exception  {
066        // The default implementation is a no-op.
067    }
068
069    @Override
070    public PooledObject<T> makeObject() throws Exception {
071        return wrap(Objects.requireNonNull(create(), () -> String.format("BasePooledObjectFactory(%s).create() = null", getClass().getName())));
072    }
073
074    /**
075     *  No-op.
076     *
077     * @param p ignored
078     */
079    @Override
080    public void passivateObject(final PooledObject<T> p) throws Exception {
081        // The default implementation is a no-op.
082    }
083
084    /**
085     * Always returns {@code true}.
086     *
087     * @param p ignored
088     *
089     * @return {@code true}
090     */
091    @Override
092    public boolean validateObject(final PooledObject<T> p) {
093        return true;
094    }
095
096    /**
097     * Wraps the provided instance with an implementation of
098     * {@link PooledObject}.
099     *
100     * @param obj the instance to wrap, should not be null.
101     *
102     * @return The provided instance, wrapped by a {@link PooledObject}
103     */
104    public abstract PooledObject<T> wrap(T obj);
105}