// File: Selection.java
// Classes: Selection
// Original Author: Jason Robbins
// $Id: Selection.java,v 1.1.1.1 1997/02/27 20:52:47 chandra Exp $

package uci.graphedit;

import java.awt.Graphics;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Event;
import java.util.Hashtable;
import java.util.Enumeration;


/** This class represents the "selection" object that is used when you
 * select one or more Figures in the drawing window. Selection's
 * (should) handle the display of handles or whatever graphics
 * indicate that something is selected, and they process events to
 * manipulate the selected DiagramElement. Needs-More-Work: in a
 * earlier version of this design DiagramElement's did all of that
 * work themselves which led to much code duplication. Unfortuanately
 * some of that code is still left over. Specificially,
 * DiagramElement's still have methods to draw their own handles.
 *
 * @see DiagramElement
 * @see DiagramElement#drawSelected */

public abstract class Selection {

  /** Construct a new selection. Empty, subclases can override */
  public Selection() { }

  /** Reply true if this selection contains the given DiagramElement */
  public abstract boolean contains(DiagramElement de);

  /** Return the DiagramElement that is contained. This probably
   * should not be implemented in this abstract class because some
   * Selection subclasses can select more than one DiagramElement. */
  //public abstract DiagramElement content();

  /** Reply true if nothing is selected. */
  public boolean isEmpty() { return size() == 0; }

  /** Reply the number of DiagramElement's selected */
  public abstract int size();

  /** Draw something that indicates a selection to the user */
  public abstract void draw(Graphics g);

  /** Some action is about to change the selected item, mark its
   * region as damaged .*/
  public abstract void startTrans();

  /** Some action has just changes the selected item, mark its region
   * as damaged .*/
  public abstract void endTrans();

  /** Get and set the graphical attributes of the selected
   * DiagramElement(s).
   *
   * @see DiagramElement#getGraphicAttribute
   * @see DiagramElement#setGraphicAttribute
   * @see DiagramElement#setGraphicAttributes */
  public abstract Object getGraphicAttribute(String k);
  public abstract void setGraphicAttribute(String k, Object v);
  public void setGraphicAttributes(Hashtable newAttrs) {
    Enumeration cur = newAttrs.keys();
    while (cur.hasMoreElements()) {
      String key = (String) cur.nextElement();
      Object val = newAttrs.get(key);
      setGraphicAttribute(key, val);
    }
  }

  /** Reply the position of the Selection. That is defined to be the
   * upper left corner of my bounding box. */
  public Point position() {
    Rectangle bbox = getBoundingBox();
    return new Point(bbox.x, bbox.y);
  }

  /** This Selection needs to be redrawn. */
  public void damagedIn(Document ed) { ed.damaged(this); }

  /** Reply true if the given mouse coordinates are inside or near
   * enough to this selection that we consider the user to have
   * clicked on it. */
  abstract boolean inside(int x, int y);
  final boolean inside(Point pnt) { return inside(pnt.x, pnt.y); }

  /** Find which handle the user clicked on, or return -1 if none. */
  public final int pickHandle(Point p) { return pickHandle(p.x, p.y); }
  public abstract int pickHandle(int x, int y);

  /** Reorder, align, or translate the selected DiagramElement(s). */
  public abstract void reorder(int function, Layer view);
  abstract void align(int direction);
  abstract void translate(int dx,int dy);

  /** Remove or dispose of the selected DiagramElement(s). */
  public abstract void removeFrom(Document ed);
  public abstract void dispose(Document ed);

  /** Move one of the handles of a selected DiagramElement. */
  public abstract void dragHandle(int mx, int my, int an_x,int an_y, int h);

  abstract Rectangle getBoundingBox();

  public boolean keyDown(Event e,int key) { return false; }
  public boolean mouseMove(Event e,int x,int y) { return false; }
  public boolean mouseDrag(Event e,int x,int y) { return false; }
  public boolean mouseDown(Event e,int x,int y) { return false; }
  public boolean mouseUp(Event e,int x,int y) { return false; }

} /* end class Selection */