fusionplace.java

来自「Rakiura JFern是一个非常轻型的带有模拟器的Petri网络框架」· Java 代码 · 共 182 行

// 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.PlaceEvent;
import org.rakiura.cpn.event.PlaceListener;
import org.rakiura.cpn.event.TokensAddedEvent;
import org.rakiura.cpn.event.TokensRemovedEvent;


/**
 * Represents a fusion place. Fusion place in Opal works as
 * a simple synchronization mechanis between two or more places.
 * The actual nets may be executed in two completely separete
 * simulators, and may work completely independently from 
 * one another, with their original places. If two or more nets are
 * instantiated from the XML, the actual fusion place connecting these
 * seperate nets must be created seperately from within the API working
 * with these nets. Fusion place should be thus treated purely as a 
 * runtime feature (not as a static feature of some petri nets).
 * 
 *<br><br>
 * FusionPlace.java<br>
 * Created: Fri Apr 12 16:47:11 2002<br>
 *
 *@author  <a href="[e-mail]">Mariusz Nowostawski</a>
 *@version 2.1.0 $Revision: 1.9 $
 *@since 2.0
 */
public class FusionPlace extends Place {

  /**/
  private List places = new ArrayList();

  /**
   * Creates a new <code>FusionPlace</code> instance.
   */
  public FusionPlace() {
  }

  
  public Multiset getTokens() {
    if (this.places.size() > 0) {
      return ((Place) this.places.get(0)).getTokens();
    } else {
      return new Multiset();
    }
  }

  /**
   * Adds given tokens to this place.
   * @param aMultiset a <code>Multiset</code> value
   */
  public void addTokens(final Multiset aMultiset) {
    if (this.places.size() > 0) {
      ((Place) this.places.get(0)).addTokens(aMultiset);
    }
  }

  public void addToken(final Object aToken) {
    if (this.places.size() > 0) {
      ((Place) this.places.get(0)).addToken(aToken);
    }
  }
  

  public void removeTokens(final Multiset aMultiset) {
    ((Place) this.places.get(0)).removeTokens(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) {
    if (this.places.size() > 0) {
      return ((Place) this.places.get(0)).removeToken(aToken);
    }
    return false;
  }

  /**
   * Removes all the tokens from this place.
   */
  public void clearTokens() {
    if (this.places.size() > 0) {
      ((Place) this.places.get(0)).clearTokens();
    }
  }

  /**
   * Adds the new Place to this Fusion Place. All added places 
   * to this fusion place will share same marking (same tokens multiset) 
   * as this fusion place. If the added place already has marking, it will be
   * reset to the existing fused places marking.
   *@param aPlace a <code>Place</code> value to be added 
   *  to this fusion place.
   */
  public void addPlace(final Place aPlace) {
    final Multiset current = aPlace.getTokens();
    final Iterator iter = this.places.iterator();
    if (iter.hasNext()) {
      aPlace.clearTokens();
      final Place existingPlace = (Place) iter.next();
      final List intersection = new ArrayList(current);
      intersection.retainAll(existingPlace.getTokens());
      final List tokensToBeAdded = new ArrayList(existingPlace.getTokens());
      tokensToBeAdded.removeAll(intersection);
      if (tokensToBeAdded.size() > 0) {
        aPlace.addTokens(tokensToBeAdded);
      }
    }
    this.places.add(aPlace);
    aPlace.addFusionPlace(this);
  }

  public void addPlaceListener(final PlaceListener aListener) {
    if (this.places.size() > 0) {
      ((Place) this.places.get(0)).addPlaceListener(aListener);
    }
  }

  /**
   * Removes a given place from this fusion place.
   *@param aPlace a <code>Place</code> value
   *@return <code>true</code> if a place was present in this fusion place 
   * and was  removed succesfully, <code>false</code> otherwise.
   */
  public boolean removePlace(final Place aPlace) {
    aPlace.removeFusionPlace(this);
    return this.places.remove(aPlace);
  }


  /**
   * Synchronization routine. This method is synchronizing all the registered places
   * with this single fusion place.
   * @param anEvent a <code>PlaceEvent</code> value
   */
  public void notify(final TokensAddedEvent anEvent) {
    final Place theEventPlace = anEvent.getPlace();
    final Multiset changed = anEvent.getTokens();
    final Iterator iter = this.places.iterator();
    while (iter.hasNext()) {
      final Place place = (Place) iter.next();
      if (place != theEventPlace)
        place.addTokensQuietly(changed);
    }
  }

  /**
   * Synchronization routine. This method is synchronizing all the registered places
   * with this single fusion place.
   * @param anEvent a <code>PlaceEvent</code> value
   */
  public void notify(final TokensRemovedEvent anEvent) {
    final Place theEventPlace = anEvent.getPlace();
    final Multiset changed = anEvent.getTokens();
    final Iterator iter = this.places.iterator();
    while (iter.hasNext()) {
      final Place place = (Place) iter.next();
      if (place != theEventPlace)
        place.removeTokensQuietly(changed);
    }
  }


} // FusionPlace
//////////////////// end of file ////////////////////