// File: SelectionSingle.java
// Classes: SelectionSingle
// Original Author: Jason Robbins
// $Id: SelectionSingle.java,v 1.1.1.1 1997/02/27 20:52:48 chandra Exp $

package uci.graphedit;

import java.awt.Event;
import java.awt.Graphics;
import java.awt.Point;



/** Shared implementations of methods for all kinds of Selections that
 * just select one thing.
 * This is an abstract class, subclasses define the look and behavior
 * of actual selections.
 * @see SelectionMultiple
 * @see SelectionHandle
 * @see SelectionBox
 */ 

public abstract class SelectionSingle extends Selection {

  /** _content refers to the DiagramElement that is selected */
  protected DiagramElement _content;

  /** Construct a new selection object that refers to the given
   * DiagramElement
   */
  public SelectionSingle(DiagramElement de) {
    if (null == de) throw new java.lang.NullPointerException();
    _content = de;
  }

  /** Reply true iff this selection contains the given DiagramElement */
  public boolean contains(DiagramElement de) { return de == _content; }

  /** Reply the DiagramElement that was selected */ 
  public DiagramElement content() { return _content; }

  /** Tell the content to start a transaction that causes damage */
  public void startTrans() { content().startTrans(); }

  /** Tell the content to end a transaction that causes damage */
  public void endTrans() { content().endTrans(); }

  /** This type of selection always refers to 1 selected DiagramElement */
  public int size() { return 1; }

  /** Draw the handles or selection box or whatever is appropriate */
  public void draw(Graphics g) {
    // needs-more-work: should manage Handle objects here
    _content.drawSelected(g);
  }

  /** Reply one of the graphical attributes of the selected DiagramElement */
  public Object getGraphicAttribute(String k) {
    return _content.getGraphicAttribute(k);
  }

  /** Set one of the graphical attributes of the selected DiagramElement */
  public void setGraphicAttribute(String k, Object v) {
    _content.setGraphicAttribute(k, v);
  }

  /** reply the position of the selected DiagramElement */
  public Point position() { return _content.position(); }

  /** This selection object needs to be redrawn, register its damaged
   * area within the given Editor */
  public void damagedIn(Document ed) { _content.damagedIn(ed); }

  /** reply true if the given point is inside this selection */
  boolean inside(int x, int y) { return _content.inside(x, y); }

  /** Tell the selected DiagramElement to move to front or back, etc. */
  public void reorder(int function, Layer view) {
    view.reorder(_content, function);
  }

  /** Do nothing because alignment only makes sense for multiple
   * selections */
  public void align(int direction) { /* do nothing */ }

  /** When the selection is told to move, move the selected
   * DiagramElement */
  void translate(int dx,int dy) {
    _content.translate(dx, dy);
  }


  /** Reply an integer handle number for the handle under the given
   * mouse point. Normally called from ModeModify.
   * @see ModeModify
   * needs-more-work: should take on more of this responsibility */
  public int pickHandle(int x, int y) { return _content.pickHandle(x, y); }

  /** Drag a handle on the selected object.  Normally called from ModeModify.
   * @see ModeModify
   */
  public void dragHandle(int mx, int my, int an_x,int an_y, int h) {
    _content.dragHandle(mx, my, an_x, an_y, h);
  }

  /** If the selection is being deleted, the selected object is
   * deleted also. This is different from just deselecting the
   * selected DiagramElement, to do that use one of the deselect
   * operations in Editor
   * @see Editor#deselectItem
   */
  public void removeFrom(Document ed) {
    _content.removeFrom(ed);
  }

  /** If the selection is being disposed, the selected object is
   * disposed also. This is different from just deselecting the
   * selected DiagramElement, to do that use one of the deselect
   * operations in Editor
   * @see Editor#deselectItem
   */ 
  public void dispose(Document ed) {
    _content.dispose(ed);
  }

  /** Pass any events along to the selected DiagramElement.
   * Subclasses of SelectionSingle may reimplement this to add
   * functionality.
   */
  public boolean keyDown(Event e,int key) {
    return _content.keyDown(e, key);
  }
  
  public boolean mouseMove(Event e,int x,int y) {
    return _content.mouseMove(e, x, y);
  }

  public boolean mouseDrag(Event e,int x,int y) {
    return _content.mouseDrag(e, x, y);
  }

  public boolean mouseDown(Event e,int x,int y) {
    return _content.mouseDown(e, x, y);
  }

  public boolean mouseUp(Event e,int x,int y) {
    return _content.mouseUp(e, x, y);
  }


} /* end class SelectionSingle */