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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.pool;
19  
20  /**
21   * A simple base implementation of <code>KeyedObjectPool</code>.
22   * Optional operations are implemented to either do nothing, return a value
23   * indicating it is unsupported or throw {@link UnsupportedOperationException}.
24   *
25   * @author Rodney Waldhoff
26   * @author Sandy McArthur
27   * @version $Revision: 1085933 $ $Date: 2011-03-27 06:40:20 -0700 (Sun, 27 Mar 2011) $
28   * @since Pool 1.0
29   */
30  public abstract class BaseKeyedObjectPool implements KeyedObjectPool {
31      
32      /**
33       * {@inheritDoc}
34       */
35      public abstract Object borrowObject(Object key) throws Exception;
36      
37      /**
38       * {@inheritDoc}
39       */
40      public abstract void returnObject(Object key, Object obj) throws Exception;
41      
42      /**
43       * <p>Invalidates an object from the pool.</p>
44       * 
45       * <p>By contract, <code>obj</code> <strong>must</strong> have been obtained
46       * using {@link #borrowObject borrowObject} using a <code>key</code> that is
47       * equivalent to the one used to borrow the <code>Object</code> in the first place.</p>
48       *
49       * <p>This method should be used when an object that has been borrowed
50       * is determined (due to an exception or other problem) to be invalid.</p>
51       *
52       * @param key the key used to obtain the object
53       * @param obj a {@link #borrowObject borrowed} instance to be returned.
54       * @throws Exception 
55       */
56      public abstract void invalidateObject(Object key, Object obj) throws Exception;
57  
58      /**
59       * Not supported in this base implementation.
60       * Always throws an {@link UnsupportedOperationException},
61       * subclasses should override this behavior.
62       * @param key ignored
63       * @throws UnsupportedOperationException
64       */
65      public void addObject(Object key) throws Exception, UnsupportedOperationException {
66          throw new UnsupportedOperationException();
67      }
68  
69      /**
70       * Not supported in this base implementation.
71       * @return a negative value.
72       * @param key ignored
73       */
74      public int getNumIdle(Object key) throws UnsupportedOperationException {
75          return -1;
76      }
77  
78      /**
79       * Not supported in this base implementation.
80       * @return a negative value.
81       * @param key ignored
82       */
83      public int getNumActive(Object key) throws UnsupportedOperationException {
84          return -1;
85      }
86  
87      /**
88       * Not supported in this base implementation.
89       * @return a negative value.
90       */
91      public int getNumIdle() throws UnsupportedOperationException {
92          return -1;
93      }
94  
95      /**
96       * Not supported in this base implementation.
97       * @return a negative value.
98       */
99      public int getNumActive() throws UnsupportedOperationException {
100         return -1;
101     }
102 
103     /**
104      * Not supported in this base implementation.
105      * @throws UnsupportedOperationException
106      */
107     public void clear() throws Exception, UnsupportedOperationException {
108         throw new UnsupportedOperationException();
109     }
110 
111     /**
112      * Not supported in this base implementation.
113      * @param key ignored
114      * @throws UnsupportedOperationException
115      */
116     public void clear(Object key) throws Exception, UnsupportedOperationException {
117         throw new UnsupportedOperationException();
118     }
119 
120     /**
121      * Close this pool.
122      * This affects the behavior of <code>isClosed</code> and <code>assertOpen</code>.
123      */
124     public void close() throws Exception {
125         closed = true;
126     }
127 
128     /**
129      * Not supported in this base implementation.
130      * Always throws an {@link UnsupportedOperationException},
131      * subclasses should override this behavior.
132      * @param factory the new KeyedPoolableObjectFactory
133      * @deprecated to be removed in pool 2.0
134      */
135     public void setFactory(KeyedPoolableObjectFactory factory) throws IllegalStateException, UnsupportedOperationException {
136         throw new UnsupportedOperationException();
137     }
138 
139     /**
140      * Has this pool instance been closed.
141      * @return <code>true</code> when this pool has been closed.
142      * @since Pool 1.4
143      */
144     protected final boolean isClosed() {
145         return closed;
146     }
147 
148     /**
149      * Throws an <code>IllegalStateException</code> when this pool has been closed.
150      * @throws IllegalStateException when this pool has been closed.
151      * @see #isClosed()
152      * @since Pool 1.4
153      */
154     protected final void assertOpen() throws IllegalStateException {
155         if(isClosed()) {
156             throw new IllegalStateException("Pool not open");
157         }
158     }
159 
160     /** Whether or not the pool is close */
161     private volatile boolean closed = false;
162 }