/* ======================================================================
The Bodington System Software License, Version 1.0
  
Copyright (c) 2001 The University of Leeds.  All rights reserved.
  
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

1.  Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.

2.  Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

3.  The end-user documentation included with the redistribution, if any,
must include the following acknowledgement:  "This product includes
software developed by the University of Leeds
(http://www.bodington.org/)."  Alternately, this acknowledgement may
appear in the software itself, if and wherever such third-party
acknowledgements normally appear.

4.  The names "Bodington", "Nathan Bodington", "Bodington System",
"Bodington Open Source Project", and "The University of Leeds" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
d.gardner@leeds.ac.uk.

5.  The name "Bodington" may not appear in the name of products derived
from this software without prior written permission of the University of
Leeds.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO,  TITLE,  THE IMPLIED WARRANTIES 
OF QUALITY  AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO 
EVENT SHALL THE UNIVERSITY OF LEEDS OR ITS CONTRIBUTORS BE LIABLE FOR 
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
POSSIBILITY OF SUCH DAMAGE.
=========================================================

This software was originally created by the University of Leeds and may contain voluntary 
contributions from others.  For more information on the Bodington Open Source Project, please 
see http://bodington.org/

====================================================================== */

package org.bodington.applet.test;

import java.awt.*;
import java.awt.dnd.*;
import java.awt.datatransfer.*;
import java.util.Hashtable;
import java.util.List;
import java.util.Iterator;
import java.io.*;
import java.io.IOException;
import javax.swing.JList;
import javax.swing.DefaultListModel;

public class DNDList extends javax.swing.JList implements java.awt.dnd.DragGestureListener, java.awt.dnd.DragSourceListener, java.awt.dnd.DropTargetListener, org.bodington.applet.test.DNDComponentInterface
{
  /**
   * enables this component to be a dropTarget
   */

  DropTarget dropTarget = null;

  /**
   * enables this component to be a Drag Source
   */
  DragSource dragSource = null;


  /**
   * constructor - initializes the DropTarget and DragSource.
   */

  public DNDList() {
    
    dropTarget = new DropTarget (this, this);
    dragSource = new DragSource();
    dragSource.createDefaultDragGestureRecognizer( this, DnDConstants.ACTION_MOVE, this);
  }

  /**
   * is invoked when you are dragging over the DropSite
   * 
   */

  public void dragEnter (DropTargetDragEvent event) {
    
    // debug messages for diagnostics 
    System.out.println( "dragEnter");
    event.acceptDrag (DnDConstants.ACTION_MOVE);
  }

  /**
   * is invoked when you are exit the DropSite without dropping
   *
   */

  public void dragExit (DropTargetEvent event) {
    System.out.println( "dragExit");
    
  }

  /**
   * is invoked when a drag operation is going on
   * 
   */

  public void dragOver (DropTargetDragEvent event) {
    System.out.println( "dragOver");
  }

  /**
   * a drop has occurred
   * 
   */

 
  public void drop (DropTargetDropEvent event) {
    
    try {
        Transferable transferable = event.getTransferable();
                   
        // we accept only Strings      
        if (transferable.isDataFlavorSupported (DataFlavor.stringFlavor)){
        
            event.acceptDrop(DnDConstants.ACTION_MOVE);
            String s = (String)transferable.getTransferData ( DataFlavor.stringFlavor);
            addElement( s );
            event.getDropTargetContext().dropComplete(true);
        } 
        else{
            event.rejectDrop();
        }
    }
    catch (IOException exception) {
        exception.printStackTrace();
        System.err.println( "Exception" + exception.getMessage());
        event.rejectDrop();
    } 
    catch (UnsupportedFlavorException ufException ) {
      ufException.printStackTrace();
      System.err.println( "Exception" + ufException.getMessage());
      event.rejectDrop();
    }
  }

  /**
   * is invoked if the use modifies the current drop gesture
   * 
   */
    

  public void dropActionChanged ( DropTargetDragEvent event ) {
  }

  /**
   * a drag gesture has been initiated
   * 
   */
  
  public void dragGestureRecognized( DragGestureEvent event) {
    
    Object selected = getSelectedValue();
    if ( selected != null ){
        StringSelection text = new StringSelection( selected.toString()); 
        
        // as the name suggests, starts the dragging
        dragSource.startDrag (event, DragSource.DefaultMoveDrop, text, this);
    } else {
        System.out.println( "nothing was selected");   
    }
  }

  /**
   * this message goes to DragSourceListener, informing it that the dragging 
   * has ended
   * 
   */

  public void dragDropEnd (DragSourceDropEvent event) {   
    if ( event.getDropSuccess()){
        removeElement();
    }
  }

  /**
   * this message goes to DragSourceListener, informing it that the dragging 
   * has entered the DropSite
   * 
   */

  public void dragEnter (DragSourceDragEvent event) {
    System.out.println( " dragEnter");
  }

  /**
   * this message goes to DragSourceListener, informing it that the dragging 
   * has exited the DropSite
   * 
   */

  public void dragExit (DragSourceEvent event) {
    System.out.println( "dragExit");
    
  }

  /**
   * this message goes to DragSourceListener, informing it that the dragging is currently 
   * ocurring over the DropSite
   * 
   */

  public void dragOver (DragSourceDragEvent event) {
    System.out.println( "dragExit");
    
  }

  /**
   * is invoked when the user changes the dropAction
   * 
   */
   
  public void dropActionChanged ( DragSourceDragEvent event) {
    System.out.println( "dropActionChanged"); 
  }

  /**
   * adds elements to itself
   * 
   */
   
   public void addElement( Object s ){
        (( DefaultListModel )getModel()).addElement (s.toString());
  }

  /**
   * removes an element from itself
   */
   
  public void removeElement(){
    (( DefaultListModel)getModel()).removeElement( getSelectedValue());
  }
  

}