// 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;/**/import java.util.ArrayList;import java.util.Collection;import java.util.Iterator;import java.util.List;import org.rakiura.cpn.event.PlaceListener;import org.rakiura.cpn.event.TokensAddedEvent;import org.rakiura.cpn.event.TokensRemovedEvent;/** * Represents a Place in the JFern Petri Net. Place is one of the elementary  * nodes in the Petri Net graph. Place contains tokens which are kept * inside a single multiset structure. * *  *<br><br> * Place.java<br> * Created: Mon Sep 25 21:23:17 2000<br> * *@author  <a href="mariusz@rakiura.org">Mariusz Nowostawski</a> *@version 2.1.0 $Revision: 1.12 $ *@since 2.0 */public class Place extends Node {    /**/  private Multiset multiset;  /**/  private List listeners = new ArrayList();  private List fusionPlaces = new ArrayList();  /**/  private List inputs = new ArrayList(10);  /**/  private List outputs = new ArrayList(10);    /**   * Creates a new <code>Place</code> instance.   */  public Place() {    this.multiset = new Multiset();  }  /**   * Creates a new <code>Place</code> instance    * with a given Place name.   * @param aName this place name.   */  public Place(final String aName) {    super(aName);    this.multiset = new Multiset();  }  /**   * Creates a new <code>Place</code> instance,    * initialized with a given multiset.   * @param aMultiset an initial <code>multiset</code>   */  public Place(final Collection aMultiset) {    this.multiset = new Multiset(aMultiset);  }  /**   * Adds an input Arc. This method is not for the user to call   * directly, it is called by newly created arcs which plug   * themselves automatically to the appropriate place.    *@return this place.    */  public Place addInput(final InputArc anArc){    this.inputs.add(anArc);    return this;  }  /**   * Adds an output Arc. This method is not for the user to call   * directly, it is called by newly created arcs which plug   * themselves automatically to the appropriate place.    *@return this Place.    */  public Place addOutput(final OutputArc anArc){    this.outputs.add(anArc);    return this;  }  /**    * Returns list of all input arcs from this place.   * <b>Note:</b> input arcs go from this place to a given    * transition, so in a sense, from the place point of view   * could be treated as outgoing arcs.   *@return set of all input arcs from this place.   */  public List inputArcs(){ return this.inputs; }  /**    * Returns list of all output arcs to this place.   * <b>Note:</b> output arcs go from a given transition   * to this place, so in a sense, from the place point of view   * could be treated as incoming arcs.   *@return set of all output arcs to this place.   */  public List outputArcs(){ return this.outputs; }  /**   * Returns all the tokens for this place.   * Returned is the reference to the copy of this place multiset.    * Use this method with caution, do not manipulate tokens via   * the returned multiset, as it will have no effect on    * the actual state of this place - use token manipulation    * methods from the Place API.   *@return this place collection of tokens   *@see #addToken   *@see #removeToken   */  public Multiset getTokens() {    return new Multiset(this.multiset);  }  /**   * Adds given tokens to this place.   *@param aMultiset a <code>multiset</code> of tokens.   */  public void addTokens(final Collection aMultiset) {    addTokensQuietly(aMultiset);    notifyFusionAdded(new TokensAddedEvent(this, new Multiset(aMultiset)));  }  /**   * Adds given tokens to this place without firing the event.   *@param aMultiset a <code>multiset</code> of tokens.   */  void addTokensQuietly(final Collection aMultiset) {    this.multiset.addAll(aMultiset);    if (this.listeners.size() > 0) {      fireTokensAddedEvent(new TokensAddedEvent(this, new Multiset(aMultiset)));    }  }  /**   * Adds new token to this place.    * Adds a new token to the existing place multiset.   *@param aToken an additonal token for this place.    */  public void addToken(final Object aToken) {    this.multiset.add(aToken);    final TokensAddedEvent event = new TokensAddedEvent(this, new Multiset(aToken));    if (this.listeners.size() > 0) {      fireTokensAddedEvent(event);    }    if (this.fusionPlaces.size() > 0) {      notifyFusionAdded(event);    }  }    /**   * Removes all tokens from the given multiset from this place.   *@param aMultiset multiset containing tokens to be removed.      */  public void removeTokens(final Collection aMultiset) {    removeTokensQuietly(aMultiset);    notifyFusionRemoved(new TokensRemovedEvent(this, new Multiset(aMultiset)));  }  /**   * Removes all tokens from the given multiset from this place without   * firing the event.   *@param aMultiset multiset containing tokens to be removed.      */  void removeTokensQuietly(final Collection aMultiset) {    this.multiset.removeAll(aMultiset);    if (this.listeners.size() > 0) {      fireTokensRemovedEvent(new TokensRemovedEvent(this, new Multiset(aMultiset)));    }  }  /**   * Removes given token from the given multiset from this place.   *@param aToken token to be removed.   *@return <code>true</code> if the token was succesfully removed,   * <code>false</code> if the token was not present in the place and    * was not removed.   */  public boolean removeToken(final Object aToken) {    final boolean result = this.multiset.remove(aToken);    final TokensRemovedEvent event = new TokensRemovedEvent(this, new Multiset(aToken));    if (this.listeners.size() > 0) {      fireTokensRemovedEvent(event);    }        if (this.fusionPlaces.size() > 0) {      notifyFusionRemoved(event);    }    return result;  }  /**   * Removes all the tokens from this place.   */  public void clearTokens() {    final TokensRemovedEvent event = new TokensRemovedEvent(this, new Multiset(this.multiset));    this.multiset.clear();    if (this.listeners.size() > 0) {      fireTokensRemovedEvent(event);     }    if (this.fusionPlaces.size() > 0) {      notifyFusionRemoved(event);    }  }  /**   * Visitor pattern.   *@param aVisitor a <code>NetVisitor</code> value   *@return a <code>NetElement</code> value   */  public NetElement apply(final NetVisitor aVisitor) {    aVisitor.place(this);    return this;  }  /**   * Registers a given PlaceListener with this place.   *@param aListener a <code>PlaceListener</code> to    * be registered with this Place.   */  public void addPlaceListener(final PlaceListener aListener) {    this.listeners.add(aListener);  }  /**   * Deregisters a given PlaceListener from this place.   *@param aListener a <code>PlaceListener</code> to    * be removed with this Place.   */  public void removePlaceListener(final PlaceListener aListener) {    this.listeners.remove(aListener);  }  /**   * Notifies all listeners about tokens being removed from this place.   *@param anEvent a TokensRemovedEvent   */  protected void fireTokensRemovedEvent(final TokensRemovedEvent anEvent) {    final Iterator l = this.listeners.iterator();    while (l.hasNext()) {      ((PlaceListener) l.next()).notify(anEvent);    }  }  /**   * Notifies all listeners about tokens being added to this place.   *@param anEvent tokens added event   */  private void fireTokensAddedEvent(final TokensAddedEvent anEvent) {    final Iterator l = this.listeners.iterator();    while (l.hasNext()) {      ((PlaceListener) l.next()).notify(anEvent);    }  }  /**   * Notifies all listeners about tokens being removed from this place.   *@param anEvent a TokensRemovedEvent   */  void notifyFusionRemoved(final TokensRemovedEvent anEvent) {    final Iterator l = this.fusionPlaces.iterator();    while (l.hasNext()) {      ((FusionPlace) l.next()).notify(anEvent);    }  }  /**   * Notifies all listeners about tokens being added to this place.   *@param anEvent tokens added event   */  void notifyFusionAdded(final TokensAddedEvent anEvent) {    final Iterator l = this.fusionPlaces.iterator();    while (l.hasNext()) {      ((FusionPlace) l.next()).notify(anEvent);    }  }    void addFusionPlace(FusionPlace aPlace) {    this.fusionPlaces.add(aPlace);  }    void removeFusionPlace(final FusionPlace aPlace) {    this.fusionPlaces.remove(aPlace);  }  /**   * Returns human readable representiation of this place.   *@return a <code>String</code> value.   */  public String toString() {    final String res = "Place: " + getName() + " ";    return res + this.multiset.toString();  }} // Place//////////////////// end of file ////////////////////