tuplesource.java

rule engine drools-2.0-beta-18

package org.drools.reteoo;

/*
 * $Id: TupleSource.java,v 1.23 2004/11/29 13:20:52 simon 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 [e-mail].
 *
 * 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
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 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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 * 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.
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 */

import org.drools.AssertionException;
import org.drools.FactException;
import org.drools.FactHandle;
import org.drools.RetractionException;

import java.io.Serializable;
import java.util.Set;

/**
 * A source of <code>ReteTuple</code> s for a <code>TupleSink</code>.
 *
 * <p>
 * Nodes that propagate <code>Tuples</code> extend this class.
 * </p>
 *
 * @see TupleSource
 * @see ReteTuple
 *
 * @author <a href="mailto:[e-mail]">bob mcwhirter </a>
 */
abstract class TupleSource
    implements
    Serializable
{
    // ------------------------------------------------------------
    // Instance members
    // ------------------------------------------------------------

    /** The destination for <code>Tuples</code>. */
    private TupleSink tupleSink;

    // ------------------------------------------------------------
    // Constructors
    // ------------------------------------------------------------

    /**
     * Construct.
     */
    TupleSource()
    {
        // intentionally left blank.
    }

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

    /**
     * Set the <code>TupleSink</code> that receives <code>Tuples</code>
     * propagated from this <code>TupleSource</code>.
     *
     * @param tupleSink
     *            The <code>TupleSink</code> to receive propagated
     *            <code>Tuples</code>.
     */
    protected void setTupleSink(TupleSink tupleSink)
    {
        this.tupleSink = tupleSink;
    }

    /**
     * Propagate the assertion of a <code>Tuple</code> to this node's
     * <code>TupleSink</code>.
     *
     * @param tuple The <code>Tuple</code> to propagate.
     * @param workingMemory the working memory session.
     *
     * @throws AssertionException If an errors occurs while attempting assertion.
     */
    protected void propagateAssertTuple(ReteTuple tuple,
                                        WorkingMemoryImpl workingMemory) throws AssertionException
    {

        this.tupleSink.assertTuple( tuple,
                                    workingMemory );
    }

    /**
     * Propagate the retration of a <code>Tuple</code> to this node's
     * <code>TupleSink</code>.
     *
     * @param key The tuple key.
     * @param workingMemory The working memory session.
     *
     * @throws RetractionException If an error occurs while attempting retraction
     *
     */
    protected void propagateRetractTuples(TupleKey key,
                                          WorkingMemoryImpl workingMemory) throws RetractionException
    {
        this.tupleSink.retractTuples( key,
                                      workingMemory );
    }

    /**
     * Propagate the modification of <code>Tuple</code> s to this node's
     * <code>TupleSink</code>.
     *
     * @param trigger The modification trigger object handle.
     * @param newTuples Modification replacement tuples.
     * @param workingMemory The working memory session.
     *
     * @throws FactException If an error occurs while attempting modification.
     */
    protected void propagateModifyTuples(FactHandle trigger,
                                         TupleSet newTuples,
                                         WorkingMemoryImpl workingMemory) throws FactException
    {
        this.tupleSink.modifyTuples( trigger,
                                     newTuples,
                                     workingMemory );
    }

    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // org.drools.reteoo.TupleSource
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    /**
     * Retrieve the <code>TupleSink</code> that receives propagated
     * <code>Tuples</code>.
     *
     * @return The <code>TupleSink</code> that receives propagated
     *         <code>Tuples</code>.
     */
    public TupleSink getTupleSink()
    {
        return this.tupleSink;
    }

    /**
     * Retrieve the available tuple <code>Declaration</code>s.
     *
     * @return The available tuple declarations.
     */
    public abstract Set getTupleDeclarations();
}