/*
* Copyright 1999-2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.tomcat.util.threads;
import org.apache.tomcat.util.buf.TimeStamp;
/**
* Expire unused objects.
*
*/
public final class Expirer implements ThreadPoolRunnable
{
private static org.apache.commons.logging.Log log=
org.apache.commons.logging.LogFactory.getLog(Expirer.class );
// 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 ) {
managedCount--;
managedObjs[ i ] = managedObjs[managedCount];
managedObjs[managedCount] = null;
}
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( log.isTraceEnabled() ) log.trace( "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( log.isTraceEnabled() ) log.trace( "TS: " + maxInactiveInterval + " " +
ts.getLastAccessedTime());
if (maxInactiveInterval < 0)
continue;
long timeIdle = timeNow - ts.getThisAccessedTime();
if (timeIdle >= maxInactiveInterval) {
if( expireCallback != null ) {
if( log.isDebugEnabled() )
log.debug( ts + " " + timeIdle + " " +
maxInactiveInterval );
expireCallback.expired( ts );
}
}
}
}
}