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1
50 package org.apache.avalon.excalibur.pool;
51
52 import java.util.ArrayList  ;
53 import java.util.List ;
54
55 import org.apache.avalon.framework.activity.Initializable;
56 import org.apache.avalon.framework.logger.AbstractLogEnabled;
57 import org.apache.avalon.framework.thread.ThreadSafe;
58 import org.apache.commons.collections.Buffer;
59 import org.apache.commons.collections.UnboundedFifoBuffer;
60
61
68 public abstract class AbstractPool
69 extends AbstractLogEnabled
70 implements Pool, ThreadSafe
71 {
72 public static final int DEFAULT_POOL_SIZE = 8;
73 protected final ObjectFactory m_factory;
74 protected List m_active = new ArrayList ();
75 protected Buffer m_ready = new UnboundedFifoBuffer();
76 protected Mutex m_mutex = new Mutex();
77 protected boolean m_initialized = false;
78 protected int m_min;
79
80
84 public AbstractPool( final ObjectFactory factory ) throws Exception
85 {
86 m_factory = factory;
87
88 if( !( this instanceof Initializable ) )
89 {
90 initialize();
91 }
92 }
93
94 protected void initialize()
95 throws Exception
96 {
97 lock();
98
99 for( int i = 0; i < AbstractPool.DEFAULT_POOL_SIZE; i++ )
100 {
101 this.m_ready.add( this.newPoolable() );
102 }
103
104 m_initialized = true;
105
106 unlock();
107 }
108
109 protected final void lock()
110 throws InterruptedException
111 {
112 m_mutex.acquire();
113 }
114
115 protected final void unlock()
116 throws InterruptedException
117 {
118 m_mutex.release();
119 }
120
121
125 protected Poolable newPoolable() throws Exception
126 {
127 Object obj = m_factory.newInstance();
128 return (Poolable)obj;
129 }
130
131
135 protected void removePoolable( Poolable poolable )
136 {
137 try
138 {
139 m_factory.decommission( poolable );
140 }
141 catch( Exception e )
142 {
143 if( getLogger().isDebugEnabled() )
144 {
145 getLogger().debug( "Error decommissioning object", e );
146 }
147 }
148 }
149
150 public final int size()
151 {
152 synchronized( this )
153 {
154 return this.m_active.size() + this.m_ready.size();
158 }
159 }
160
161 public abstract Poolable get() throws Exception ;
162
163 public abstract void put( Poolable object );
164
165 protected void internalGrow( final int amount )
166 throws Exception
167 {
168 for( int i = 0; i < amount; i++ )
169 {
170 try
171 {
172 m_ready.add( newPoolable() );
173 }
174 catch( final Exception e )
175 {
176 if( null != getLogger() && getLogger().isDebugEnabled() )
177 {
178 Class createdClass = m_factory.getCreatedClass();
179 if( createdClass == null )
180 {
181 getLogger().debug( "factory created class was null so a new "
182 + "instance could not be created.", e );
183 }
184 else
185 {
186 getLogger().debug( createdClass.getName() +
187 ": could not be instantiated.", e );
188 }
189 }
190
191 throw e;
192 }
193 }
194 }
195
196 protected void internalShrink( final int amount )
197 throws Exception
198 {
199 for( int i = 0; i < amount; i++ )
200 {
201 if( m_ready.size() > m_min )
202 {
203 try
204 {
205 this.removePoolable( (Poolable)m_ready.remove() );
206 }
207 catch( final Exception e )
208 {
209 if( null != getLogger() && getLogger().isDebugEnabled() )
210 {
211 getLogger().debug( m_factory.getCreatedClass().getName() +
212 ": improperly decommissioned.", e );
213 }
214 }
215 }
216 }
217 }
218 }
219 |
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