/*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
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* 5. Products derived from this software may not be called "Apache"
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*
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* [Additional notices, if required by prior licensing conditions]
*
*/
package org.apache.tomcat.util.threads;
import org.apache.tomcat.util.buf.TimeStamp;
/**
* Expire unused objects.
*
*/
public final class Expirer implements ThreadPoolRunnable
{
// We can use Event/Listener, but this is probably simpler
// and more efficient
public static interface ExpireCallback {
public void expired( TimeStamp o );
}
private int checkInterval = 60;
private Reaper reaper;
ExpireCallback expireCallback;
public Expirer() {
}
// ------------------------------------------------------------- Properties
public int getCheckInterval() {
return checkInterval;
}
public void setCheckInterval(int checkInterval) {
this.checkInterval = checkInterval;
}
public void setExpireCallback( ExpireCallback cb ) {
expireCallback=cb;
}
// -------------------- Managed objects --------------------
static final int INITIAL_SIZE=8;
TimeStamp managedObjs[]=new TimeStamp[INITIAL_SIZE];
TimeStamp checkedObjs[]=new TimeStamp[INITIAL_SIZE];
int managedLen=managedObjs.length;
int managedCount=0;
public void addManagedObject( TimeStamp ts ) {
synchronized( managedObjs ) {
if( managedCount >= managedLen ) {
// What happens if expire is on the way ? Nothing,
// expire will do it's job on the old array ( GC magic )
// and the expired object will be marked as such
// Same thing would happen ( and did ) with Hashtable
TimeStamp newA[]=new TimeStamp[ 2 * managedLen ];
System.arraycopy( managedObjs, 0, newA, 0, managedLen);
managedObjs = newA;
managedLen = 2 * managedLen;
}
managedObjs[managedCount]=ts;
managedCount++;
}
}
public void removeManagedObject( TimeStamp ts ) {
for( int i=0; i< managedCount; i++ ) {
if( ts == managedObjs[i] ) {
synchronized( managedObjs ) {
managedObjs[ i ] = managedObjs[managedCount-1];
managedCount--;
}
return;
}
}
}
// --------------------------------------------------------- Public Methods
public void start() {
// Start the background reaper thread
if( reaper==null) {
reaper=new Reaper("Expirer");
reaper.addCallback( this, checkInterval * 1000 );
}
reaper.startReaper();
}
public void stop() {
reaper.stopReaper();
}
// -------------------------------------------------------- Private Methods
// ThreadPoolRunnable impl
public Object[] getInitData() {
return null;
}
public void runIt( Object td[] ) {
long timeNow = System.currentTimeMillis();
if( dL > 2 ) debug( "Checking " + timeNow );
int checkedCount;
synchronized( managedObjs ) {
checkedCount=managedCount;
if(checkedObjs.length < checkedCount)
checkedObjs = new TimeStamp[managedLen];
System.arraycopy( managedObjs, 0, checkedObjs, 0, checkedCount);
}
for( int i=0; i< checkedCount; i++ ) {
TimeStamp ts=checkedObjs[i];
checkedObjs[i] = null;
if (ts==null || !ts.isValid())
continue;
long maxInactiveInterval = ts.getMaxInactiveInterval();
if( dL > 3 ) debug( "TS: " + maxInactiveInterval + " " +
ts.getLastAccessedTime());
if (maxInactiveInterval < 0)
continue;
long timeIdle = timeNow - ts.getThisAccessedTime();
if (timeIdle >= maxInactiveInterval) {
if( expireCallback != null ) {
if( dL > 0 )
debug( ts + " " + timeIdle + " " +
maxInactiveInterval );
expireCallback.expired( ts );
}
}
}
}
private static final int dL=0;
private void debug( String s ) {
System.out.println("Expirer: " + s );
}
}