package org.drools.reteoo;
/*
* $Id: JoinNode.java,v 1.45 2005/05/08 16:13:33 memelet 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.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.drools.AssertionException;
import org.drools.RetractionException;
/**
* A two-input Rete-OO <i>join node </i>.
*
* @see org.drools.reteoo.TupleSource
* @see org.drools.reteoo.TupleSink
*
* @author <a href="mailto:bob@eng.werken.com">bob mcwhirter </a>
*/
class JoinNode extends TupleSource
{
// ------------------------------------------------------------
// Instance members
// ------------------------------------------------------------
/** The left input <code>TupleSource</code>. */
private final TupleSource leftInput;
/** The right input <code>TupleSource</code>. */
private final TupleSource rightInput;
/** <code>Declarations</code> in both left and right input sources combined. */
private final Set tupleDeclarations;
/** <code>Declarations</code> common to both left and right input sources. */
private final Set commonDeclarations;
// ------------------------------------------------------------
// Constructors
// ------------------------------------------------------------
/**
* Construct.
*
* @param leftInput The left input <code>TupleSource</code>.
* @param rightInput The right input <code>TupleSource</code>.
*/
public JoinNode( TupleSource leftInput,
TupleSource rightInput )
{
this.leftInput = leftInput;
this.rightInput = rightInput;
this.tupleDeclarations = determineTupleDeclarations( );
this.commonDeclarations = determineCommonDeclarations( );
}
// ------------------------------------------------------------
// Instance methods
// ------------------------------------------------------------
/**
* Set up the <code>Set</code> of common <code>Declarations</code>
* across the two input <code>TupleSources</code>.
*/
private Set determineCommonDeclarations()
{
Set commonDeclarations = new HashSet( this.leftInput.getTupleDeclarations( ) );
commonDeclarations.retainAll( this.rightInput.getTupleDeclarations( ) );
return commonDeclarations.isEmpty( ) ? Collections.EMPTY_SET : Collections.unmodifiableSet( commonDeclarations );
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// org.drools.reteoo.JoinNode
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/**
* Retrieve the set of common <code>Declarations</code> across the two
* input <code>TupleSources</code>.
*
* @return The <code>Set</code> of common <code>Declarations</code>.
*/
public Set getCommonDeclarations()
{
return this.commonDeclarations;
}
/**
* Propagate joined asserted tuples.
*
* @param joinedTuples The tuples to propagate.
* @param workingMemory The working memory session.
* @throws AssertionException If an errors occurs while asserting.
*/
private void propagateAssertTuples( TupleSet joinedTuples,
WorkingMemoryImpl workingMemory ) throws AssertionException
{
Iterator tupleIter = joinedTuples.iterator( );
while ( tupleIter.hasNext( ) )
{
propagateAssertTuple( ( ReteTuple ) tupleIter.next( ),
workingMemory );
}
}
/**
* Assert a new <code>Tuple</code> from the left input.
*
* @param tuple The <code>Tuple</code> being asserted.
* @param workingMemory The working memory seesion.
* @throws AssertionException If an error occurs while asserting.
*/
void assertLeftTuple( ReteTuple tuple,
WorkingMemoryImpl workingMemory ) throws AssertionException
{
TupleSet joinedTuples = workingMemory.getJoinMemory( this ).addLeftTuple( tuple );
if ( !joinedTuples.isEmpty( ) )
{
propagateAssertTuples( joinedTuples,
workingMemory );
}
}
/**
* Assert a new <code>Tuple</code> from the right input.
*
* @param tuple The <code>Tuple</code> being asserted.
* @param workingMemory The working memory seesion.
* @throws AssertionException If an error occurs while asserting.
*/
void assertRightTuple( ReteTuple tuple,
WorkingMemoryImpl workingMemory ) throws AssertionException
{
TupleSet joinedTuples = workingMemory.getJoinMemory( this ).addRightTuple( tuple );
if ( !joinedTuples.isEmpty( ) )
{
propagateAssertTuples( joinedTuples,
workingMemory );
}
}
/**
* Retract tuples.
*
* @param key The tuple key.
* @param workingMemory The working memory seesion.
* @throws RetractionException If an error occurs while retracting.
*/
public void retractTuples( TupleKey key,
WorkingMemoryImpl workingMemory ) throws RetractionException
{
if ( workingMemory.getJoinMemory( this ).removeTuples( key ) )
{
propagateRetractTuples( key,
workingMemory );
}
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// org.drools.reteoo.TupleSource
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/**
* Retrieve the <code>Set</code> of <code>Declaration</code>s. in the
* propagated <code>Tuples</code>.
*
* @see Declaration
*
* @return The <code>Set</code> of <code>Declarations</code> in progated
* <code>Tuples</code>.
*/
public Set getTupleDeclarations()
{
return this.tupleDeclarations;
}
public void attach()
{
leftInput.addTupleSink( new JoinNodeInput( this,
JoinNodeInput.LEFT ) );
rightInput.addTupleSink( new JoinNodeInput( this,
JoinNodeInput.RIGHT ) );
}
private Set determineTupleDeclarations()
{
Set decls = new HashSet( leftInput.getTupleDeclarations( ) );
decls.addAll( rightInput.getTupleDeclarations( ) );
return Collections.unmodifiableSet( decls );
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
public String toString()
{
return "[JoinNode: common=" + this.commonDeclarations + "; decls=" + this.tupleDeclarations + "]";
}
public int hashCode()
{
return this.leftInput.hashCode( ) ^ this.rightInput.hashCode( );
}
public boolean equals( Object object )
{
if ( this == object )
{
return true;
}
if ( object == null || getClass( ) != object.getClass( ) )
{
return false;
}
JoinNode other = ( JoinNode ) object;
return this.leftInput.equals( other.leftInput ) && this.rightInput.equals( other.rightInput );
}
}