notnode.java

jboss规则引擎

package org.drools.reteoo;

/*
 * Copyright 2005 JBoss Inc
 * 
 * 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.
 */

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.drools.common.BetaNodeBinder;
import org.drools.common.DefaultFactHandle;
import org.drools.spi.PropagationContext;
import org.drools.util.LinkedList;
import org.drools.util.LinkedListObjectWrapper;

/**
 * <code>NotNode</code> extends <code>BetaNode</code> to perform tests for
 * the non existence of a Fact plus one or more conditions. Where none existence
 * is found the left ReteTuple is copied and propgated. Further to this it
 * maintains the "truth" by cancelling any
 * <code>Activation<code>s that are nolonger 
 * considered true by the assertion of ReteTuple's or FactHandleImpl.  Tuples are considered to be asserted from the left input and facts from the right input.
 * The <code>BetaNode</code> provides the BetaMemory to store assserted ReteTuples and <code>FactHandleImpl<code>s. Each fact handle is stored in the right 
 * memory as a key in a <code>HashMap</code>, the value is an <code>ObjectMatches</code> instance which maintains a <code>LinkedList of <code>TuplesMatches - 
 * The tuples that are matched with the handle. the left memory is a <code>LinkedList</code> of <code>ReteTuples</code> which maintains a <code>HashMa</code>, 
 * where the keys are the matching <code>FactHandleImpl</code>s and the value is populated <code>TupleMatche</code>es, the keys are matched fact handles. 
 * <code>TupleMatch</code> maintains a <code>List</code> of resulting joins, where there is joined <code>ReteTuple</code> per <code>TupleSink</code>.
 * 
 * @author <a href="mailto:[e-mail]">Mark Proctor</a>
 * @author <a href="mailto:[e-mail]">Bob McWhirter</a>
 *
 */
public class NotNode extends BetaNode {
    /**
     * 
     */
    private static final long serialVersionUID = 5876745507400274713L;
    static int                notAssertObject  = 0;
    static int                notAssertTuple   = 0;

    // ------------------------------------------------------------
    // Instance methods
    // ------------------------------------------------------------

    /**
     * Construct.
     * 
     * @param leftInput
     *            The left input <code>TupleSource</code>.
     * @param rightInput
     *            The right input <code>TupleSource</code>.
     */
    NotNode(final int id,
            final TupleSource leftInput,
            final ObjectSource rightInput) {
        super( id,
               leftInput,
               rightInput,
               new BetaNodeBinder() );
    }

    /**
     * Construct.
     * 
     * @param leftInput
     *            The left input <code>TupleSource</code>.
     * @param rightInput
     *            The right input <code>TupleSource</code>.
     */
    NotNode(final int id,
            final TupleSource leftInput,
            final ObjectSource rightInput,
            final BetaNodeBinder joinNodeBinder) {
        super( id,
               leftInput,
               rightInput,
               joinNodeBinder );
    }

    /**
     * Assert a new <code>ReteTuple</code> from the left input. It iterates
     * over the right <code>FactHandleImpl</code>'s if no matches are found
     * the a copy of the <code>ReteTuple</code> is made and propagated.
     * 
     * @param tuple
     *            The <code>Tuple</code> being asserted.
     * @param context
     *            The <code>PropagationContext</code>
     * @param workingMemory
     *            The working memory seesion.
     */
    public void assertTuple(final ReteTuple leftTuple,
                            final PropagationContext context,
                            final ReteooWorkingMemory workingMemory) {
        final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );

        memory.add( workingMemory,
                    leftTuple );

        final BetaNodeBinder binder = getJoinNodeBinder();

        for ( final Iterator it = memory.rightObjectIterator( workingMemory,
                                                              leftTuple ); it.hasNext(); ) {
            final ObjectMatches objectMatches = (ObjectMatches) it.next();
            final DefaultFactHandle handle = objectMatches.getFactHandle();
            attemptJoin( leftTuple,
                         handle,
                         objectMatches,
                         binder,
                         workingMemory );
        }

        if ( leftTuple.matchesSize() == 0 ) {
            propagateAssertTuple( leftTuple,
                                  context,
                                  workingMemory );
        }

    }

    /**
     * Assert a new <code>FactHandleImpl</code> from the right input. If it
     * matches any left ReteTuple's that already has propagations then those
     * propagations are retracted.
     * 
     * @param handle
     *            The <code>FactHandleImpl</code> being asserted.
     * @param context
     *            The <code>PropagationContext</code>
     * @param workingMemory
     *            The working memory seesion.
     */
    public void assertObject(final DefaultFactHandle handle,
                             final PropagationContext context,
                             final ReteooWorkingMemory workingMemory) {

        final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );
        final ObjectMatches objectMatches = memory.add( workingMemory,
                                                        handle );

        final BetaNodeBinder binder = getJoinNodeBinder();

        for ( final Iterator it = memory.leftTupleIterator( workingMemory,
                                                            handle ); it.hasNext(); ) {
            final ReteTuple leftTuple = (ReteTuple) it.next();
            final int previousSize = leftTuple.matchesSize();
            attemptJoin( leftTuple,
                         handle,
                         objectMatches,
                         binder,
                         workingMemory );
            if ( previousSize == 0 && leftTuple.matchesSize() != 0 ) {
                propagateRetractTuple( leftTuple,
                                       context,
                                       workingMemory );
            }
        }
    }

    /**
     * Retract the <code>FactHandleImpl</code>. If the handle has any
     * <code>ReteTuple</code> matches then those matches copied are propagated
     * as new joins.
     * 
     * @param handle
     *            the <codeFactHandleImpl</code> being retracted
     * @param context
     *            The <code>PropagationContext</code>
     * @param workingMemory
     *            The working memory seesion.
     * @throws AssertionException
     */
    public void retractObject(final DefaultFactHandle handle,
                              final PropagationContext context,
                              final ReteooWorkingMemory workingMemory) {
        final BetaMemory memory = (BetaMemory) workingMemory.getNodeMemory( this );
        final ObjectMatches objectMatches = memory.remove( workingMemory,
                                                           handle );

        for ( TupleMatch tupleMatch = objectMatches.getFirstTupleMatch(); tupleMatch != null; tupleMatch = (TupleMatch) tupleMatch.getNext() ) {
            final ReteTuple leftTuple = tupleMatch.getTuple();
            final int previousSize = leftTuple.matchesSize();
            leftTuple.removeMatch( handle );

            if ( previousSize != 0 && leftTuple.matchesSize() == 0 ) {
                propagateAssertTuple( leftTuple,
                                      context,
                                      workingMemory );
            }
        }
    }

    /**
     * Retract the