package org.drools.reteoo;
/*
* $Id: Rete.java,v 1.6 2005/08/14 22:44:12 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.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.drools.FactException;
import org.drools.rule.Rule;
import org.drools.spi.ObjectType;
import org.drools.spi.PropagationContext;
/**
* The Rete-OO network.
*
* This node accepts an <code>Object</code>, and simply propagates it to all
* <code>ObjectTypeNode</code> s for type testings.
*
* @see ObjectTypeNode
*
* @author <a href="mailto:bob@eng.werken.com">bob mcwhirter </a>
*/
class Rete extends ObjectSource
implements
Serializable,
ObjectSink
{
// ------------------------------------------------------------
// Instance members
// ------------------------------------------------------------
/** The set of <code>ObjectTypeNodes</code>. */
private final Map objectTypeNodes = new HashMap( );
private final List rulesToUpdate = new ArrayList( );
// ------------------------------------------------------------
// Constructors
// ------------------------------------------------------------
/**
* Construct.
*/
public Rete()
{
super( 0 );
}
// ------------------------------------------------------------
// Instance methods
// ------------------------------------------------------------
/**
* Assert a new fact object into this <code>RuleBase</code> and the
* specified <code>WorkingMemory</code>.
*
* @param handle
* The fact handle.
* @param object
* The object to assert.
* @param workingMemory
* The working memory session.
*
* @throws FactException
* if an error occurs during assertion.
*/
public void assertObject(Object object,
FactHandleImpl handle,
PropagationContext context,
WorkingMemoryImpl workingMemory) throws FactException
{
Iterator nodeIter = getObjectTypeNodeIterator( );
while ( nodeIter.hasNext( ) )
{
((ObjectTypeNode) nodeIter.next( )).assertObject( object,
handle,
context,
workingMemory );
}
}
/**
* Retract a fact object from this <code>RuleBase</code> and the specified
* <code>WorkingMemory</code>.
*
* @param handle
* The handle of the fact to retract.
* @param workingMemory
* The working memory session.
*
* @throws FactException
* if an error occurs during retraction.
*/
public void retractObject(FactHandleImpl handle,
PropagationContext context,
WorkingMemoryImpl workingMemory) throws FactException
{
Iterator nodeIter = getObjectTypeNodeIterator( );
while ( nodeIter.hasNext( ) )
{
((ObjectTypeNode) nodeIter.next( )).retractObject( handle,
context,
workingMemory );
}
}
/**
* Retrieve all <code>ObjectTypeNode</code> children of this node.
*
* @return The <code>Set</code> of <code>ObjectTypeNodes</code>.
*/
Collection getObjectTypeNodes()
{
return this.objectTypeNodes.values( );
}
/**
* Retrieve an <code>Iterator</code> over the <code>ObjectTypeNode</code>
* children of this node.
*
* @return An <code>Iterator</code> over <code>ObjectTypeNodes</code>.
*/
Iterator getObjectTypeNodeIterator()
{
return this.objectTypeNodes.values( ).iterator( );
}
/**
* Retrieve an <code>ObjectTypeNode</code> keyed by
* <code>ObjectType</code>.
*
* @param objectType
* The <code>ObjectType</code> key.
*
* @return The matching <code>ObjectTypeNode</code> if one has already
* been created, else <code>null</code>.
*/
ObjectTypeNode getObjectTypeNode(ObjectType objectType)
{
return (ObjectTypeNode) this.objectTypeNodes.get( objectType );
}
/**
* Retrieve an <code>ObjectTypeNode</code> keyed by
* <code>ObjectType</code>, creating one, if necessary.
*
* @param objectType
* The <code>ObjectType</code> key.
*
* @return The matching <code>ObjectTypeNode</codeb>.
*/
ObjectTypeNode getOrCreateObjectTypeNode(ObjectType objectType)
{
ObjectTypeNode node = getObjectTypeNode( objectType );
if ( node == null )
{
node = new ObjectTypeNode( 0,
objectType,
this );
node.attach( );
}
this.rulesToUpdate.add( node );
return node;
}
/**
* Add an <code>ObjectTypeNode</code> child to this <code>Rete</code>.
*
* @param node
* The node to add.
*/
private void addObjectTypeNode(ObjectTypeNode node)
{
this.objectTypeNodes.put( node.getObjectType( ),
node );
}
/**
* Adds the <code>TupleSink</code> so that it may receive
* <code>Tuples</code> propagated from this <code>TupleSource</code>.
*
* @param tupleSink
* The <code>TupleSink</code> to receive propagated
* <code>Tuples</code>.
*/
protected void addObjectSink(ObjectSink objectSink)
{
addObjectTypeNode( (ObjectTypeNode) objectSink );
}
public void attach()
{
// do nothing this is the root node
}
void addRule(Rule rule)
{
}
void updateWorkingMemory(WorkingMemoryImpl workingMemory) throws FactException
{
Iterator it = this.rulesToUpdate.iterator();
ObjectTypeNode node = null;
PropagationContext context = new PropagationContextImpl( PropagationContext.ASSERTION,
null,
null );
while( it.hasNext() )
{
node = ( ObjectTypeNode ) it.next();
node.updateNewRule( workingMemory,
context );
}
}
void ruleAdded()
{
Iterator it = this.rulesToUpdate.iterator();
ObjectTypeNode node = null;
while( it.hasNext() )
{
node = ( ObjectTypeNode ) it.next();
node.ruleAttached();
it.remove();
}
}
}