package com.bbn.openmap.tools.dnd;

import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragSourceListener;
import java.awt.dnd.InvalidDnDOperationException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import com.bbn.openmap.util.Debug;

/**
 * A DragGestureListener that supports multiple catchers.
 * 
 * @author matt
 * @author last modified by $Author$
 * @version $Revision$ $Date$
 */
public class MultiCatcherDragGestureListener implements DragGestureListener {

  protected DragSourceListener dsl;

  // Supported catchers must subclass DefaultDnDCatcher as it includes the method
  // dragGestureRecognized. Perhaps this method should be elevated to the
  // DNDListener to allow a more generic DragGestureListener? TODO
  protected List dndCatchers = new LinkedList();

  // Debug flag used for draggesture debugging. Could be "draggesturelistener"
  // per the single catcher implementation.
  public final static String DEBUG_DRAG = "dnd";

  /**
   * Note that DefaultDnDCatcher is a DragSourceListener itself, so dndCatcher and dsl can be the
   * same object.
   */
  public MultiCatcherDragGestureListener(DragSourceListener dsl) {
    this.dsl = dsl;
    Debug.message(DEBUG_DRAG, "Constructor: MultiCatcherDragGestureListener");
  }

  public void addCatcher(DefaultDnDCatcher catcher) {
    dndCatchers.add(catcher);
  }

  /**
   * A <code>DragGestureRecognizer</code> has detected a platform-dependent drag initiating
   * gesture and is notifying this listener in order for it to initiate the action for the user.
   * <P>
   * 
   * @param dge the <code>DragGestureEvent</code> describing the gesture that has just occurred
   */

  public void dragGestureRecognized(DragGestureEvent dge) {

    Debug.message(DEBUG_DRAG, "MultiCatcherDragGestureListener dragGestureRecognized");

    for (Iterator catcher = dndCatchers.iterator(); catcher.hasNext();) {
      DefaultDnDCatcher c = (DefaultDnDCatcher) catcher.next();
      try {
        c.startDragAction(dge, dsl);
      }
      catch (InvalidDnDOperationException idoe) {
        Debug.message(DEBUG_DRAG, "MultiCatcherDragGestureListener InvalidDnDOperationException");
      }
    }
  }
}