// 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
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// 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
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// DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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// SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
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// File: ActionSelectNext.java
// Classes: ActionSelectNext
// Original Author: jrobbins@ics.uci.edu
// $Id: ActionSelectNext.java,v 1.5 1997/06/10 23:42:23 jrobbins Exp $

package uci.graphedit;

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

/** Action to select the next (or previous) DiagramElement in the
 *  editor's current view.  This is very convienent for moving among
 *  lots of small diagram elements.  It also provides a simple example
 *  of an Action that is bound to a key.
 *  <A HREF="../features.html#select_by_tab_key">
 *  <TT>FEATURE: select_by_tab_key</TT></A>
 *
 * @see ModeSelect#bindKeys */

public class ActionSelectNext extends Action {

  ////////////////////////////////////////////////////////////////
  // constants

  public static final String DIR = "Direction";
  public static final String DIR_NEXT = "Next";
  public static final String DIR_PREV = "Previous";

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

  public ActionSelectNext() { }
  public ActionSelectNext(String d) { setArg(DIR, d); }
  public ActionSelectNext(boolean next) {
    setArg(DIR, next ? DIR_NEXT : DIR_PREV);
  }

  ////////////////////////////////////////////////////////////////
  // Action API

  public String name() { return "Select Next DiagramElement in Layer"; }

  public void doIt(java.awt.Event e) {
    SelectionSingle curSel;
    DiagramElement newDE = null;
    int offset = 1;
    String dir = (String) getArg(DIR);
    if (DIR_PREV.equals(dir) || dir == null && e.shiftDown()) offset = -1;
    Editor ce = Globals.curEditor();
    SelectionMultiple selections = ce.selection();
    Vector diagramContents = ce.view().contents();
    int diagramSize = diagramContents.size();
    int newIndex = diagramSize + 1;

    if (selections.size() == 0) newIndex = 0;
    else if (selections.size() == 1) {
      DiagramElement curDE;
      curSel = (SelectionSingle) selections.contents().firstElement();
      curDE = (DiagramElement) curSel.content();
      int curIndex = diagramContents.indexOf(curDE);
      newIndex = (curIndex + offset + diagramSize) % diagramSize;
    }
    if (diagramSize > newIndex)
      newDE = (DiagramElement) diagramContents.elementAt(newIndex);
    if (newDE != null) ce.selectItem(newDE);
  }

  public void undoIt() {
    System.out.println("Undo does not make sense for ActionSelectNext");
  }

} /* end class ActionSelectNext */