    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 *      https://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     * Constructs a new instance.
    037     */
    038    public BasePooledObjectFactory() {
    039        // empty
    040    }
    041
    042    /**
    043     *  No-op.
    044     *
    045     *  @param p ignored
    046     */
    047    @Override
    048    public void activateObject(final PooledObject<T> p) throws Exception {
    049        // The default implementation is a no-op.
    050    }
    051
    052    /**
    053     * Creates an object instance, to be wrapped in a {@link PooledObject}.
    054     * <p>This method <strong>must</strong> support concurrent, multi-threaded
    055     * invocation.</p>
    056     *
    057     * @return an instance to be served by the pool, not null.
    058     * @throws Exception if there is a problem creating a new instance,
    059     *    this will be propagated to the code requesting an object.
    060     */
    061    public abstract T create() throws Exception;
    062
    063    /**
    064     *  No-op.
    065     *
    066     *  @param p ignored
    067     */
    068    @Override
    069    public void destroyObject(final PooledObject<T> p) throws Exception  {
    070        // The default implementation is a no-op.
    071    }
    072
    073    @Override
    074    public PooledObject<T> makeObject() throws Exception {
    075        return wrap(Objects.requireNonNull(create(), () -> String.format("BasePooledObjectFactory(%s).create() = null", getClass().getName())));
    076    }
    077
    078    /**
    079     *  No-op.
    080     *
    081     * @param p ignored
    082     */
    083    @Override
    084    public void passivateObject(final PooledObject<T> p) throws Exception {
    085        // The default implementation is a no-op.
    086    }
    087
    088    /**
    089     * Always returns {@code true}.
    090     *
    091     * @param p ignored
    092     * @return {@code true}
    093     */
    094    @Override
    095    public boolean validateObject(final PooledObject<T> p) {
    096        return true;
    097    }
    098
    099    /**
    100     * Wraps the provided instance with an implementation of
    101     * {@link PooledObject}.
    102     *
    103     * @param obj the instance to wrap, should not be null.
    104     * @return The provided instance, wrapped by a {@link PooledObject}
    105     */
    106    public abstract PooledObject<T> wrap(T obj);
    107}