basicnet.java

Rakiura JFern是一个非常轻型的带有模拟器的Petri网络框架

// 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.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.rakiura.cpn.event.PlaceListener;
import org.rakiura.cpn.event.TransitionListener;


/**
 * Implements a basic Petri Net. This implementation is based on two
 * HashMaps.  
 * 
 *<br><br>
 * BasicNet.java<br>
 * Created: Tue Sep 26 15:46:46 2000<br>
 *
 *@author  <a href="[e-mail]">Mariusz Nowostawski</a>
 *@version 2.1.0 $Revision: 1.9 $
 *@since 1.0
 */
public class BasicNet extends Node
  implements Net {

  /**/
  private boolean cachedTransitions = false;
  /**/
  private List allTransitions ;

  /**/
  private Map set_forID = new HashMap();
  /**/
  private Map set_forName = new HashMap();


  /**
   * Creates new instance of the Net. 
   */
  public BasicNet() {
  }

  
  /**
   * Creates a new <code>BasicNet</code> instance with a given name.
   * @param name a <code>String</code> name value for this Net.
   */
  public BasicNet(String name){    
    super(name);
  }

  /**
   * Adds given PlaceListener to all Places in this net.
   *@param aListener a <code>PlaceListener</code> to be 
   *  registered with all the places in this net.
   *@since 2.0
   */
  public void addPlaceListener(final PlaceListener aListener) {
    final Iterator i = places().iterator();
    while (i.hasNext()) {
      ((Place) i.next()).addPlaceListener(aListener);
    }
  }

  /**
   * Adds given TransitionListener to all Transitions in this net.
   *@param aListener a <code>TransitionListener</code> to be 
   *  registered with all the transitions in this net.
   *@since 2.0
   */
  public void addTransitionListener(final TransitionListener aListener) {
    final Iterator i = transitions().iterator();
    while (i.hasNext()) {
      ((Transition) i.next()).addTransitionListener(aListener);
    }
  }


  /** 
   * Adds a node to the net.
   *@param node NetElement to be added to the net.
   *@return this net. */
  public Net add(NetElement node) {
    this.set_forName.put(node.getName(), node);
    this.set_forID.put(node.getID(), node);
    this.cachedTransitions = false;
    return this;
  }

  /**
   * Removes the specified node from the net.
   *@param node NetElement to be removed.
   *@return null if there was no such element in the net, or the
   * removed node. */
  public NetElement remove(NetElement node) {
    this.set_forName.remove(node);
    this.cachedTransitions = false;
    return (NetElement)this.set_forID.remove(node);
  }

  /**
   * Looks up a node by its ID.
   *@param id ID of the node.
   *@return the node object or null if not found. */
  public NetElement forID(String id) {
    return (NetElement) this.set_forID.get(id);
  }

  /**
   * Looks up a node by its name. 
   *@param name Name of the node.
   *@return the node object or null if not found. */
  public NetElement forName(String name) {
    return (NetElement) this.set_forName.get(name);
  }

  /**
   * Returns all the transitions from this net.
   *@return list of all the transitions. */
  public List transitions() {
    if (cachedTransitions) {
      return new ArrayList(allTransitions);
    } else {
      final List list = new ArrayList();
      final NetVisitor walker = new NetVisitorAdapter() {
          public void transition(Transition transition) {
            list.add(transition);
          }
        };
      final Iterator iter = set_forID.values().iterator();
      while (iter.hasNext()) {
        ((NetElement) iter.next()).apply(walker);
      }
      this.allTransitions = new ArrayList(list);
      this.cachedTransitions = true;
      return list;
    }
  }

  /**
   * Returns all the places from this net.
   *@return list with all the places. */
  public List places() {
    final List list = new ArrayList();
    final NetVisitor walker = new NetVisitorAdapter() {
        public void place(Place place) {
          list.add(place);
        }
      };
    final Iterator iter = set_forID.values().iterator();
    while(iter.hasNext()){
      ((NetElement)iter.next()).apply(walker);
    }
    return list;
  }

  /**
   * Visitor pattern.
   * @param aVisitor a <code>NetVisitor</code> value
   * @return a <code>NetElement</code> value
   */
  public NetElement apply(final NetVisitor aVisitor) {
    aVisitor.net(this);
    return this;
  }


  /**
   * Returns the current marking of the net.
   *@return current marking of the net. 
   */
  public Marking marking() {
    final Marking m = new Marking();
    final Iterator iter = places().iterator();
    while (iter.hasNext()) {
      final Place p = (Place) iter.next();
      m.put(p, p.getTokens());
    }
    return m;
  }

  /**
   * Sets new marking for the entire net. If some places are not
   * referenced in the new marking, the existing marking is left
   * unchanged.
   *@param aMarking new Marking for the entire net.
   *@return previous marking of the net. 
   */
  public Marking setMarking(final Marking aMarking) {
    final Marking old = marking();
    final Iterator iter = marking().places().iterator();
    while (iter.hasNext()) {
      final Place p = (Place) iter.next();
      p.clearTokens();
      p.addTokens(aMarking.forID(p.getID()));
    }
    return old;
  }

  /**
   * Resets the marking in the entire net.
   *@return previous marking of the net. */
  public Marking resetMarking() {
    final Marking old = marking();
    final Iterator iter = places().iterator();
    while(iter.hasNext()) {
      ((Place) iter.next()).clearTokens();
    }
    return old;
  }

  /**
   * Rehashes the names of all the net elements. This method should be
   * used to update the internal net datastructures after changing 
   * the name of any, already inserted into Net, net elements.
   */
  public void rehash() {
    this.set_forName.clear();
    final NetVisitor walker = new NetVisitorAdapter() {
        public void transition(Transition t) {
          set_forName.put(t.getName(), t);
        }
        public void place(Place t) {
          set_forName.put(t.getName(), t);
        }
        public void inputArc(InputArc t) {
          set_forName.put(t.getName(), t);
        }
        public void outputArc(OutputArc t) {
          set_forName.put(t.getName(), t);
        }
      };
    final Iterator iter = this.set_forID.values().iterator();
    while (iter.hasNext()) {
      ((NetElement) iter.next()).apply(walker);
    }
    
  }

  /**
   * /
   * @return a <code>String</code> value
   */
  public String toString() {
    String res = "(Network: ";
    final Iterator iter = this.set_forID.values().iterator();
    while (iter.hasNext()) {
      res += iter.next().toString();
    }
    return res + ")";
  }

} // BasicNet
//////////////////// end of file ////////////////////