Place.java example

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ptii-master
/* A Petri net place.

 Copyright (c) 2001-2005 The Regents of the University of California.
 All rights reserved.
 Permission is hereby granted, without written agreement and without
 license or royalty fees, to use, copy, modify, and distribute this
 software and its documentation for any purpose, provided that the above
 copyright notice and the following two paragraphs appear in all copies
 of this software.

 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
 THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
 SUCH DAMAGE.

 THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
 PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
 CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
 ENHANCEMENTS, OR MODIFICATIONS.

 PT_COPYRIGHT_VERSION_2
 COPYRIGHTENDKEY
 */
package ptolemy.domains.petrinet.kernel;

import ptolemy.actor.lib.Transformer;
import ptolemy.data.IntToken;
import ptolemy.data.expr.Parameter;
import ptolemy.data.type.BaseType;
import ptolemy.kernel.CompositeEntity;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;

//////////////////////////////////////////////////////////////////////////
//// Place

/**
 A Petri net place. A Petri net place is a basic component of the Petri Net
 model. Another basic component is the Transition. A place is connected to
 transitions. It contains an integer as the marking of the
 place, which represents the number of tokens in the place.
 The operation of the Petri net is controlled by the marking
 and the weights of arcs connecting places and transitions.

 The methods here are used to manipulate the integer marking.
 The TemporaryMarking is used for checking whether a transition
 is ready or not.

 @author  Yuke Wang and Edward A. Lee
 @version $Id$
 @since Ptolemy II 2.0
 @Pt.ProposedRating Red (yukewang)
 @Pt.AcceptedRating Red (cxh@eecs)
 */
public class Place extends Transformer {
    /** Create a new actor in the specified container with the specified
     *  name.  The name must be unique within the container or an exception
     *  is thrown. The container argument must not be null, or a
     *  NullPointerException will be thrown.
     *
     *  @param container The container.
     *  @param name The name of this actor within the container.
     *  @exception IllegalActionException If this actor cannot be contained
     *   by the proposed container (see the setContainer() method).
     *  @exception NameDuplicationException If the name coincides with
     *   an entity already in the container.
     */
    public Place(CompositeEntity container, String name)
            throws IllegalActionException, NameDuplicationException {
        super(container, name);

        initialMarking = new Parameter(this, "initialMarking");
        initialMarking.setExpression("0");
        initialMarking.setTypeEquals(BaseType.INT);

        input.setMultiport(true);
        input.setTypeEquals(BaseType.GENERAL);
        output.setMultiport(true);

        output.setTypeEquals(BaseType.GENERAL);
    }

    ///////////////////////////////////////////////////////////////////
    ////                         ports and parameters              ////

    /** The number of initial tokens in the place. This is an integer. */
    public Parameter initialMarking;

    ///////////////////////////////////////////////////////////////////
    ////                         public methods                    ////

    /** getMarking() is to get the _currentMarking of the place.
     *  @return the currentMarking of the place.
     */
    public int getMarking() {
        return _currentMarking;
    }

    /** getTemporaryMarking() is to get the temporaryMarking of the place.
     *  temporaryMarking is used for checking whether the _currentMarking
     *  of the place is bigger than the sum of all links between the place
     *  and a transition. TemporaryMarking is used in Transition.prefire.
     *  @return the _temporaryMarking of the place.
     *  @see #setTemporaryMarking(int)
     */
    public int getTemporaryMarking() {
        return _temporaryMarking;
    }

    /** Increase the _currentMarking.
     *  @param i the number to be increased for the marking in the place.
     */
    public void increaseMarking(int i) {
        _currentMarking = _currentMarking + i;
    }

    /** Decrease the _currentMarking.
     *  @param i the number to be decreased for the marking in the place.
     */
    public void decreaseMarking(int i) {
        _currentMarking = _currentMarking - i;
    }

    /** Decrease the _temporaryMarking by i.
     *  @param i the number to be decreased for the TemporaryMarking
     *   in the place.
     */
    public void decreaseTemporaryMarking(int i) {
        _temporaryMarking = _temporaryMarking - i;
    }

    /** Set the _temporaryMarking.
     *  @param i set the TemporaryMarking of the place to i.
     *  @see #getTemporaryMarking()
     */
    public void setTemporaryMarking(int i) {
        _temporaryMarking = i;
    }

    /** Set the current marking equal to the initial marking.
     *  @exception IllegalActionException If the initialMarking parameter
     *   throws it.
     */
    public void initialize() throws IllegalActionException {
        _currentMarking = ((IntToken) initialMarking.getToken()).intValue();
        _temporaryMarking = _currentMarking;
    }

    ///////////////////////////////////////////////////////////////////
    ////                         private variables                 ////

    /** Current marking. */
    private int _currentMarking = 0;

    /** Temporary marking. */
    private int _temporaryMarking = 0;
}