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