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