// Copyright (c) 1996-98 The Regents of the University of California. All
// Rights Reserved. Permission to use, copy, modify, and distribute this
// software and its documentation for educational, research and non-profit
// purposes, without fee, and without a written agreement is hereby granted,
// provided that the above copyright notice and this paragraph appear in all
// copies. Permission to incorporate this software into commercial products may
// be obtained by contacting the University of California. David F. Redmiles
// Department of Information and Computer Science (ICS) University of
// California Irvine, California 92697-3425 Phone: 714-824-3823. This software
// program and documentation are copyrighted by The Regents of the University
// of California. The software program and documentation are supplied "as is",
// without any accompanying services from The Regents. The Regents do not
// warrant that the operation of the program will be uninterrupted or
// error-free. The end-user understands that the program was developed for
// research purposes and is advised not to rely exclusively on the program for
// any reason. IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY
// PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
// INCLUDING LOST PROFITS, 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 OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
// ENHANCEMENTS, OR MODIFICATIONS.

// File: NetArc.java
// Classes: NetArc
// Original Author: ics125b spring 1996
// $Id: NetArc.java,v 1.14 1997/06/10 23:43:15 jrobbins Exp $

package uci.graphedit;

import java.awt.*;
import java.io.*;
import java.util.*;

/** This class models an arc in our underlying connected graph model.
 *  <A HREF="../features.html#graph_representation_arcs">
 *  <TT>FEATURE: graph_representation_arcs</TT></A>
 */

public abstract class NetArc extends NetPrimitive {

  ////////////////////////////////////////////////////////////////
  // instance variables

  /** The start and end ports of this arc. */
  private NetPort _sourcePort;
  private NetPort _destPort;

  ////////////////////////////////////////////////////////////////
  // constructors

  /** Construct a new NetArc */
  public NetArc() { }

  ////////////////////////////////////////////////////////////////
  // accessors

  public void sourcePort(NetPort s) { _sourcePort = s; }
  public NetPort sourcePort() { return _sourcePort; }
  public void destPort(NetPort d) { _destPort = d; }
  public NetPort destPort() { return _destPort; }

  public NetPort otherEnd(NetPort oneEnd) {
    NetPort sp = sourcePort();
    if (sp == oneEnd) { return destPort(); }
    else { return sp; }
  }

  ////////////////////////////////////////////////////////////////
  // net-level hooks

  /** Connect the source and destination ports, iff they agree to
   * being connected (i.e., canConnectTo() returns true). Reply true
   * on success. This method is noramlly called after a new arc
   * instance is made. Maybe this behavior should be in a constructor,
   * but I want to use Class#newInstancel so constructors do not get
   * any arguments. */
  public boolean connect(NetPort s, NetPort d) {
    if (s.canConnectTo(d) && d.canConnectTo(s)) {
      sourcePort(s);		destPort(d);
      s.addArc(this); 		d.addArc(this);
      s.postConnect(d); 	d.postConnect(s);
      return true;
    }
    return false;
  }

  ////////////////////////////////////////////////////////////////
  // Editor API

  /** Remove this NetArc from the underlying connected graph model. */
  public void dispose() {
    System.out.println("disposing: " + toString());
    if (sourcePort() != null && destPort() != null) {
      _sourcePort.removeArc(this);
      _destPort.removeArc(this);
      // needs-more-work: assumes no parallel arcs!
      _sourcePort.postDisconnect(destPort());
      _destPort.postDisconnect(sourcePort());
      Vector v = new Vector(2);
      v.addElement(Globals.REMOVE);
      v.addElement(this);
      setChanged();
      System.out.println("NetArc notifying:" + toString());
      notifyObservers(v);
    }
  }

  ////////////////////////////////////////////////////////////////
  // diagram-level operations

  /** The perspective to use in views of a given type */
  public ArcPerspective perspectiveFor(Layer lay) {
    NetNode sourceNode = _sourcePort.parentNode();
    NetNode destNode = _destPort.parentNode();
    Perspective sourcePerspective = sourceNode.perspectiveFor(lay);
    Perspective destPerspective = destNode.perspectiveFor(lay);
    Fig sourcePortFig = sourcePerspective.getPortFig(_sourcePort);
    Fig destPortFig = destPerspective.getPortFig(_destPort);
    ArcPerspective ap = makePerspective(lay);
    ap.sourcePortFig(sourcePortFig);
    ap.destPortFig(destPortFig);
    ap.sourcePerspective(sourcePerspective);
    ap.destPerspective(destPerspective);
    ap.owner(this);
    return ap;
  }

  /** Override this method if you want your Arc subclasses to have a
   * different look. */
  public abstract ArcPerspective makePerspective(Layer lay);

} /* end class NetArc */