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