package org.drools.reteoo;
/*
* $Id: Scheduler.java,v 1.2 2005/08/14 22:34:41 mproctor Exp $
*
* Copyright 2001-2003 (C) The Werken Company. All Rights Reserved.
*
* Redistribution and use of this software and associated documentation
* ("Software"), with or without modification, are permitted provided that the
* following conditions are met:
*
* 1. Redistributions of source code must retain copyright statements and
* notices. Redistributions must also contain a copy of this document.
*
* 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 name "drools" must not be used to endorse or promote products derived
* from this Software without prior written permission of The Werken Company.
* For written permission, please contact bob@werken.com.
*
* 4. Products derived from this Software may not be called "drools" nor may
* "drools" appear in their names without prior written permission of The Werken
* Company. "drools" is a trademark of The Werken Company.
*
* 5. Due credit should be given to The Werken Company. (http://werken.com/)
*
* THIS SOFTWARE IS PROVIDED BY THE WERKEN COMPANY AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE WERKEN COMPANY OR ITS CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Timer;
import java.util.TimerTask;
import org.drools.spi.AsyncExceptionHandler;
import org.drools.spi.ConsequenceException;
/**
* Scheduler for rules requiring truth duration.
*
* @author <a href="mailto:bob@werken.com">bob mcwhirter </a>
*/
final class Scheduler
{
// ------------------------------------------------------------
// Class members
// ------------------------------------------------------------
/** Singleton instance. */
private static final Scheduler INSTANCE = new Scheduler( );
// ------------------------------------------------------------
// Class methods
// ------------------------------------------------------------
/**
* Retrieve the singleton instance.
*
* @return The singleton instance.
*/
static Scheduler getInstance()
{
return INSTANCE;
}
// ------------------------------------------------------------
// Instance members
// ------------------------------------------------------------
/** Alarm manager. */
private final Timer scheduler;
/** Scheduled tasks. */
private final Map tasks;
private AsyncExceptionHandler exceptionHandler;
// ------------------------------------------------------------
// Constructors
// ------------------------------------------------------------
/**
* Construct.
*/
private Scheduler()
{
this.scheduler = new Timer( true );
this.tasks = new HashMap( );
}
/**
* Schedule an agenda item.
*
* @param item
* The item to schedule.
* @param workingMemory
* The working memory session.
*/
void scheduleAgendaItem(AgendaItem item,
WorkingMemoryImpl workingMemory)
{
Date now = new Date( );
Date then = new Date( now.getTime( ) + item.getRule( ).getDuration( ).getDuration( item.getTuple( ) ) );
TimerTask task = new AgendaItemFireListener( item,
workingMemory );
this.scheduler.schedule( task,
then );
this.tasks.put( item,
task );
}
/**
* Cancel an agenda item.
*
* @param item
* The item to cancle.
*/
void cancelAgendaItem(AgendaItem item)
{
TimerTask task = (TimerTask) this.tasks.remove( item );
if ( task != null )
{
task.cancel( );
}
}
void setAsyncExceptionHandler(AsyncExceptionHandler handler)
{
this.exceptionHandler = handler;
}
AsyncExceptionHandler getAsyncExceptionHandler()
{
return this.exceptionHandler;
}
public int size()
{
return this.tasks.size( );
}
/**
* Fire listener.
*
* @author <a href="mailto:bob@eng.werken.com">bob mcwhirter </a>
*/
class AgendaItemFireListener extends TimerTask
{
// ------------------------------------------------------------
// Instance members
// ------------------------------------------------------------
/** The agenda item. */
private AgendaItem item;
/** The working-memory session. */
private WorkingMemoryImpl workingMemory;
// ------------------------------------------------------------
// Constructors
// ------------------------------------------------------------
/**
* Construct.
*
* @param item
* The agenda item.
* @param workingMemory
* The working memory session.
*/
AgendaItemFireListener(AgendaItem item,
WorkingMemoryImpl workingMemory)
{
this.item = item;
this.workingMemory = workingMemory;
}
// ------------------------------------------------------------
// Instance methods
// ------------------------------------------------------------
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// fr.dyade.jdring.AlarmListener
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/**
* Handle the firing of an alarm.
*/
public void run()
{
try
{
this.item.fire( this.workingMemory );
Scheduler.this.tasks.remove( item );
}
catch ( ConsequenceException e )
{
Scheduler.getInstance( ).getAsyncExceptionHandler( ).handleException( this.workingMemory,
e );
}
}
}
}