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 * Provides the possible states that a {@link PooledObject} may be in.
021 *
022 * @version $Revision: $
023 *
024 * @since 2.0
025 */
026public enum PooledObjectState {
027    /**
028     * In the queue, not in use.
029     */
030    IDLE,
031
032    /**
033     * In use.
034     */
035    ALLOCATED,
036
037    /**
038     * In the queue, currently being tested for possible eviction.
039     */
040    EVICTION,
041
042    /**
043     * Not in the queue, currently being tested for possible eviction. An
044     * attempt to borrow the object was made while being tested which removed it
045     * from the queue. It should be returned to the head of the queue once
046     * eviction testing completes.
047     * TODO: Consider allocating object and ignoring the result of the eviction
048     *       test.
049     */
050    EVICTION_RETURN_TO_HEAD,
051
052    /**
053     * In the queue, currently being validated.
054     */
055    VALIDATION,
056
057    /**
058     * Not in queue, currently being validated. The object was borrowed while
059     * being validated and since testOnBorrow was configured, it was removed
060     * from the queue and pre-allocated. It should be allocated once validation
061     * completes.
062     */
063    VALIDATION_PREALLOCATED,
064
065    /**
066     * Not in queue, currently being validated. An attempt to borrow the object
067     * was made while previously being tested for eviction which removed it from
068     * the queue. It should be returned to the head of the queue once validation
069     * completes.
070     */
071    VALIDATION_RETURN_TO_HEAD,
072
073    /**
074     * Failed maintenance (e.g. eviction test or validation) and will be / has
075     * been destroyed
076     */
077    INVALID,
078
079    /**
080     * Deemed abandoned, to be invalidated.
081     */
082    ABANDONED,
083
084    /**
085     * Returning to the pool.
086     */
087    RETURNING
088}