package org.drools.reteoo;
/*
* $Id: JoinMemory.java,v 1.54 2005/02/02 00:23:21 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.Iterator;
import java.util.Set;
import org.drools.rule.Declaration;
/**
* Memory for left and right inputs of a <code>JoinNode</code>.
*
* @author <a href="mailto:bob@eng.werken.com">bob mcwhirter </a>
* @see ReteTuple
*/
class JoinMemory
implements
Serializable
{
// ------------------------------------------------------------
// Instance members
// ------------------------------------------------------------
/** Left-side tuples. */
private final TupleSet leftTuples;
/** Right-side tuples. */
private final TupleSet rightTuples;
/** Tuple column declarations. */
private final Set tupleDeclarations;
/** Join column declarations. */
private final Set commonDeclarations;
// ------------------------------------------------------------
// Constructors
// ------------------------------------------------------------
/**
* Construct.
*
* @param tupleDeclarations
* @param commonDeclarations
*/
JoinMemory( Set tupleDeclarations,
Set commonDeclarations )
{
this.leftTuples = new TupleSet( );
this.rightTuples = new TupleSet( );
this.tupleDeclarations = tupleDeclarations;
this.commonDeclarations = commonDeclarations;
}
// ------------------------------------------------------------
// Instance methods
// ------------------------------------------------------------
/**
* Remove tuples from this memory.
*
* @param key The key for the tuples to be removed.
* @return <code>true</code> if at least one tuple was removed; <code>false</code> otherwise.
*/
boolean removeTuples(TupleKey key)
{
// Single | doesn't short circuit. THIS IS IMPORTANT as we need to
// ensure all relevant left AND right side tuples are removed.
return this.leftTuples.removeAllTuples( key )
| this.rightTuples.removeAllTuples( key );
}
/**
* Add a <code>ReteTuple</code> received from the <code>JoinNode's</code>
* left input to the left side of this memory, and attempt to join to
* existing <code>Tuples</code> in the right side.
*
* @param tuple The <code>Tuple</code> to add to the left side memory.
* @return A <code>Set</code> of <code>Tuples</code> successfully
* created by joining the incoming <code>tuple</code> against
* existing <code>Tuples</code> on the right side memory.
* @see JoinNode
* @see ReteTuple
*/
TupleSet addLeftTuple(ReteTuple tuple)
{
this.leftTuples.addTuple( tuple );
return attemptJoin( tuple,
this.rightTuples );
}
/**
* Add a <code>ReteTuple</code> received from the <code>JoinNode's</code>
* right input to the right side of this memory, and attempt to join to
* existing <code>Tuples</code> in the left side.
*
* @param tuple The <code>Tuple</code> to add to the right side memory.
* @return A <code>Set</code> of <code>Tuples</code> successfully
* created by joining the incoming <code>tuple</code> against
* existing <code>Tuples</code> on the left side memory.
* @see JoinNode
* @see ReteTuple
*/
TupleSet addRightTuple(ReteTuple tuple)
{
this.rightTuples.addTuple( tuple );
return attemptJoin( tuple,
this.leftTuples );
}
/**
* Attempt to join a given <code>tuple</code> against all tuples in a specified <code>TupleSet</code>.
*
* @param tuple The <code>Tuple</code> to attempt joining.
* @param tupleSet The Tuples to attempt joining to the parameter.
* @return The newly joined tuples.
*/
private TupleSet attemptJoin( ReteTuple tuple,
TupleSet tupleSet )
{
TupleSet newJoined = new TupleSet( tupleSet.size( ), 1 );
attemptJoin( tuple,
tupleSet,
newJoined );
return newJoined;
}
/**
* Attempt to join a given <code>tuple</code> against all tuples in a specified <code>TupleSet</code>.
*
* @param tuple The <code>Tuple</code> to attempt joining.
* @param tupleSet The Tuples to attempt joining to the parameter.
* @param newJoined The <code>TupleSet</code> into which newly joined tuples will be added.
*/
private void attemptJoin( ReteTuple tuple,
TupleSet tupleSet,
TupleSet newJoined )
{
Iterator tupleIter = tupleSet.iterator( );
while ( tupleIter.hasNext( ) )
{
attemptJoin( tuple,
( ReteTuple ) tupleIter.next( ),
newJoined );
}
}
private void attemptJoin( ReteTuple left,
ReteTuple right,
TupleSet newJoined )
{
Iterator declIter = this.commonDeclarations.iterator( );
Declaration eachDecl;
while ( declIter.hasNext( ) )
{
eachDecl = (Declaration) declIter.next( );
if ( !left.getKey( ).get( eachDecl ).equals( right.getKey( ).get( eachDecl ) ) )
{
return;
}
}
newJoined.addTuple( new ReteTuple( left,
right ) );
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// java.lang.Object
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/**
* Produce debug string.
*
* @return The debug string.
*/
public String toString()
{
return "[JoinMemory \n\tleft=" + this.leftTuples + "\n\tright=" + this.rightTuples + "]";
}
public void dump()
{
System.err.println( "----" );
ReteTuple tuple;
Iterator it1 = this.leftTuples.iterator( );
while ( it1.hasNext( ) )
{
tuple = (ReteTuple) it1.next( );
System.err.println( "tuple" );
Iterator it2 = this.tupleDeclarations.iterator( );
while ( it2.hasNext( ) )
{
Declaration decl = (Declaration) it2.next( );
Object object = tuple.get( decl );
TupleKey key = tuple.getKey( );
System.err.println( "dump memory leftTuples:" + key.get( decl ) + ":" + decl + ":" + object );
}
}
it1 = this.rightTuples.iterator( );
while ( it1.hasNext( ) )
{
tuple = (ReteTuple) it1.next( );
Iterator it2 = this.tupleDeclarations.iterator( );
while ( it2.hasNext( ) )
{
Declaration decl = (Declaration) it2.next( );
Object object = tuple.get( decl );
TupleKey key = tuple.getKey( );
System.err.println( "dump memory rightTuples:" + key.get( decl ) + ":" + decl + ":" + object );
}
}
System.err.println( "----" );
}
}