1
2
3 /*
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
5 *
6 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
7 *
8 * Portions Copyright Apache Software Foundation.
9 *
10 * The contents of this file are subject to the terms of either the GNU
11 * General Public License Version 2 only ("GPL") or the Common Development
12 * and Distribution License("CDDL") (collectively, the "License"). You
13 * may not use this file except in compliance with the License. You can obtain
14 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
15 * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
16 * language governing permissions and limitations under the License.
17 *
18 * When distributing the software, include this License Header Notice in each
19 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
20 * Sun designates this particular file as subject to the "Classpath" exception
21 * as provided by Sun in the GPL Version 2 section of the License file that
22 * accompanied this code. If applicable, add the following below the License
23 * Header, with the fields enclosed by brackets [] replaced by your own
24 * identifying information: "Portions Copyrighted [year]
25 * [name of copyright owner]"
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29 * If you wish your version of this file to be governed by only the CDDL or
30 * only the GPL Version 2, indicate your decision by adding "[Contributor]
31 * elects to include this software in this distribution under the [CDDL or GPL
32 * Version 2] license." If you don't indicate a single choice of license, a
33 * recipient has the option to distribute your version of this file under
34 * either the CDDL, the GPL Version 2 or to extend the choice of license to
35 * its licensees as provided above. However, if you add GPL Version 2 code
36 * and therefore, elected the GPL Version 2 license, then the option applies
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38 * holder.
39 */
40 package org.apache.tomcat.util.threads;
41
42 import java.io.IOException;
43 import java.util.Enumeration;
44 import java.util.Hashtable;
45 import java.util.Vector;
46 import org.apache.tomcat.util.buf;
47
48 /**
49 * Expire unused objects.
50 *
51 */
52 public final class Expirer implements ThreadPoolRunnable
53 {
54
55 private static com.sun.org.apache.commons.logging.Log log=
56 com.sun.org.apache.commons.logging.LogFactory.getLog(Expirer.class );
57
58 // We can use Event/Listener, but this is probably simpler
59 // and more efficient
60 public static interface ExpireCallback {
61 public void expired( TimeStamp o );
62 }
63
64 private int checkInterval = 60;
65 private Reaper reaper;
66 ExpireCallback expireCallback;
67
68 public Expirer() {
69 }
70
71 // ------------------------------------------------------------- Properties
72 public int getCheckInterval() {
73 return checkInterval;
74 }
75
76 public void setCheckInterval(int checkInterval) {
77 this.checkInterval = checkInterval;
78 }
79
80 public void setExpireCallback( ExpireCallback cb ) {
81 expireCallback=cb;
82 }
83
84 // -------------------- Managed objects --------------------
85 static final int INITIAL_SIZE=8;
86 TimeStamp managedObjs[]=new TimeStamp[INITIAL_SIZE];
87 TimeStamp checkedObjs[]=new TimeStamp[INITIAL_SIZE];
88 int managedLen=managedObjs.length;
89 int managedCount=0;
90
91 public void addManagedObject( TimeStamp ts ) {
92 synchronized( managedObjs ) {
93 if( managedCount >= managedLen ) {
94 // What happens if expire is on the way ? Nothing,
95 // expire will do it's job on the old array ( GC magic )
96 // and the expired object will be marked as such
97 // Same thing would happen ( and did ) with Hashtable
98 TimeStamp newA[]=new TimeStamp[ 2 * managedLen ];
99 System.arraycopy( managedObjs, 0, newA, 0, managedLen);
100 managedObjs = newA;
101 managedLen = 2 * managedLen;
102 }
103 managedObjs[managedCount]=ts;
104 managedCount++;
105 }
106 }
107
108 public void removeManagedObject( TimeStamp ts ) {
109 for( int i=0; i< managedCount; i++ ) {
110 if( ts == managedObjs[i] ) {
111 synchronized( managedObjs ) {
112 managedObjs[ i ] = managedObjs[managedCount-1];
113 managedCount--;
114 }
115 return;
116 }
117 }
118 }
119
120 // --------------------------------------------------------- Public Methods
121
122 public void start() {
123 // Start the background reaper thread
124 if( reaper==null) {
125 reaper=new Reaper("Expirer");
126 reaper.addCallback( this, checkInterval * 1000 );
127 }
128
129 reaper.startReaper();
130 }
131
132 public void stop() {
133 reaper.stopReaper();
134 }
135
136
137 // -------------------------------------------------------- Private Methods
138
139 // ThreadPoolRunnable impl
140
141 public Object[] getInitData() {
142 return null;
143 }
144
145 public void runIt( Object td[] ) {
146 long timeNow = System.currentTimeMillis();
147 if( dL > 2 ) debug( "Checking " + timeNow );
148 int checkedCount;
149 synchronized( managedObjs ) {
150 checkedCount=managedCount;
151 if(checkedObjs.length < checkedCount)
152 checkedObjs = new TimeStamp[managedLen];
153 System.arraycopy( managedObjs, 0, checkedObjs, 0, checkedCount);
154 }
155 for( int i=0; i< checkedCount; i++ ) {
156 TimeStamp ts=checkedObjs[i];
157 checkedObjs[i] = null;
158
159 if (ts==null || !ts.isValid())
160 continue;
161
162 long maxInactiveInterval = ts.getMaxInactiveInterval();
163 if( dL > 3 ) debug( "TS: " + maxInactiveInterval + " " +
164 ts.getLastAccessedTime());
165 if (maxInactiveInterval < 0)
166 continue;
167
168 long timeIdle = timeNow - ts.getLastAccessedTime();
169
170 if (timeIdle >= maxInactiveInterval) {
171 if( expireCallback != null ) {
172 if( dL > 0 )
173 debug( ts + " " + timeIdle + " " +
174 maxInactiveInterval );
175 expireCallback.expired( ts );
176 }
177 }
178 }
179 }
180
181 private static final int dL=0;
182 private void debug( String s ) {
183 if (log.isDebugEnabled())
184 log.debug("Expirer: " + s );
185 }
186 }