// This is copyrighted source file, part of Rakiura JFern package. // See the file LICENSE for copyright information and the terms and conditions// for copying, distributing and modifications of Rakiura JFern package.// Copyright (C) 1999-2002 by Mariusz Nowostawski and others  [http://www.rakiura.org]package org.rakiura.cpn;/** * Represents an output Arc in Petri Net. *  *<br><br> * OutputArc.java<br> * Created: Mon Sep 25 11:49:12 2000<br> * *@author <a href="mailto:mariusz@rakiura.org">Mariusz Nowostawski</a> *@version 2.1.0 $Revision: 1.7 $ *@since 1.0 */public class OutputArc extends AbstractArc {    /**   * Default expression. */  private Expression expr = new Expression();  /**   * Creates a new <code>OutputArcAdapter</code> instance.   */  protected OutputArc() {  }  /**   * Creates a new <code>OutputArcAdapter</code> instance.   * @param aFrom a <code>Transition</code> value   * @param aTo a <code>Place</code> value   */  public OutputArc(final Transition aFrom, final Place aTo){    super(aFrom, aTo);    aFrom.addOutput(this);    aTo.addOutput(this);  }    /**   * Returns a multiset of tokens expressed by the inscription.    * In JFern the inscription language is Java.   * @return a <code>Multiset</code> value   */  public Multiset expression() {    return this.expr.evaluate();  }  /**   * Sets the expression for this arc.   *@param anExpr an <code>Expression</code> value   */  public void setExpression(final Expression anExpr) {    this.expr = anExpr;  }  /**   * Visitor pattern.   * @param aVisitor a <code>NetVisitor</code> value   * @return a <code>NetElement</code> value   */  public NetElement apply(final NetVisitor aVisitor) {    aVisitor.outputArc(this);    return this;  }  /**   * Represents an expression for the output arc.   *    *<br><br>   * OutputArcExpression.java<br>   * Created: Tue Apr 23 23:34:20 2002<br>   *   *@author  <a href="mariusz@rakiura.org">Mariusz</a>   *@version $Revision: 1.7 $ $Date: 2002/04/26 06:23:18 $   *@since 2.0   */  public class Expression implements Context {    /**     * Evaluates this expression.     * Expression returns single multiset. This method      * implements the actual expression on the output arc.     * This implementation returns an empty multiset, which     * is equivalent to an empty arc inscription. User     * needs to overwrite this method to provide some output     * arc functionality, token generation, and the like.     *@return a single multiset.     */    public Multiset evaluate(){       return new Multiset();     }            public void var(final String aVariable) {      getContext().var(aVariable);    }        public void var(final int aNumber) {      getContext().var(aNumber);    }    public Object get(final String aVariable) {      return getContext().get(aVariable);    }        public Multiset getMultiset() {      return getContext().getMultiset();    }      } // OutputArcExpression} // OutputArc//////////////////// end of file ////////////////////