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1
17 package org.apache.excalibur.mpool;
18
19 import org.apache.avalon.framework.activity.Disposable;
20 import org.apache.avalon.framework.activity.Initializable;
21 import org.apache.commons.collections.BoundedFifoBuffer;
22 import org.apache.commons.collections.Buffer;
23 import org.apache.commons.collections.BufferUnderflowException;
24
25
33 public final class BlockingFixedSizePool
34 implements Pool, Disposable, Initializable
35 {
36 private boolean m_disposed = false;
37 private final Buffer m_buffer;
38 private final ObjectFactory m_factory;
39 private final long m_timeout;
40 private final int m_maxSize;
41
42
43 protected final Object  m_semaphore = new Object ();
44
45 public BlockingFixedSizePool( ObjectFactory factory, int size )
46 throws Exception
47 {
48 this( factory, size, 1000 );
49 }
50
51 public BlockingFixedSizePool( ObjectFactory factory, int size, long timeout )
52 throws Exception
53 {
54 m_timeout = ( timeout < 1 ) ? 0 : timeout;
55 m_buffer = new BoundedFifoBuffer( size );
56 m_maxSize = size;
57 m_factory = factory;
58 }
59
60 public void initialize()
61 throws Exception
62 {
63 for( int i = 0; i < m_maxSize; i++ )
64 {
65 m_buffer.add( newInstance() );
66 }
67 }
68
69 public Object acquire()
70 {
71 if( m_disposed )
72 {
73 throw new IllegalStateException ( "Cannot get an object from a disposed pool" );
74 }
75
76 Object object = null;
77
78 synchronized( m_semaphore )
79 {
80 if( m_buffer.isEmpty() )
81 {
82 long blockStart = System.currentTimeMillis();
83
84 if( m_timeout > 0 )
85 {
86 long blockWait = m_timeout;
87
88 do
89 {
90 try
91 {
92 m_semaphore.wait( blockWait );
93 }
94 catch( InterruptedException ie )
95 {
96 }
97
98 if( m_disposed )
99 {
100 throw new IllegalStateException ( "Pool disposed of while waiting for resources to free up" );
101 }
102
103 if( m_buffer.isEmpty() )
104 {
105 blockWait = m_timeout -
106 ( System.currentTimeMillis() - blockStart );
107 }
108 } while( m_buffer.isEmpty() && blockWait > 0 );
109 }
110 else
111 {
112 do
113 {
114 try
115 {
116 m_semaphore.wait();
117 }
118 catch( InterruptedException ie )
119 {
120 }
121
122 if( m_disposed )
123 {
124 throw new IllegalStateException ( "Pool disposed of while waiting for resources to free up" );
125 }
126 } while( m_buffer.isEmpty() );
127 }
128 }
129
130 try
131 {
132 object = m_buffer.remove();
133 }
134 catch( BufferUnderflowException bufe )
135 {
136 }
138 }
139
140 if( object == null )
141 {
142 throw new IllegalStateException ( "Timeout exceeded without acquiring resource." );
143 }
144
145 return object;
146 }
147
148 public void release( Object object )
149 {
150 synchronized( m_semaphore )
151 {
152 if( m_disposed )
153 {
154 try
155 {
156 m_factory.dispose( object );
157 }
158 catch( Exception e )
159 {
160 }
162 }
163 else
164 {
165 if( m_buffer.size() < m_maxSize )
166 {
167 m_buffer.add( PoolUtil.recycle( object ) );
168 m_semaphore.notify();
169 }
170 else
171 {
172 try
173 {
174 m_factory.dispose( object );
175 }
176 catch( Exception e )
177 {
178 }
180 }
181 }
182 }
183 }
184
185 public Object newInstance()
186 throws Exception
187 {
188 return m_factory.newInstance();
189 }
190
191 public void dispose()
192 {
193 m_disposed = true;
194
195 synchronized( m_semaphore )
196 {
197 while( !m_buffer.isEmpty() )
198 {
199 try
200 {
201 m_factory.dispose( m_buffer.remove() );
202 }
203 catch( Exception e )
204 {
205 }
207 }
208
209 m_semaphore.notifyAll();
210 }
211 }
212 }
213
214 |
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