net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/dnd/BasicSelectionTransferDragAdapter.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2003 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.ui.dnd;
  12
  13 import org.eclipse.jface.util.Assert;
  14 import org.eclipse.jface.viewers.ISelection;
  15 import org.eclipse.jface.viewers.ISelectionProvider;
  16 import org.eclipse.swt.dnd.DND;
  17 import org.eclipse.swt.dnd.DragSourceAdapter;
  18 import org.eclipse.swt.dnd.DragSourceEvent;
  19 import org.eclipse.swt.dnd.Transfer;
  20
  21 public class BasicSelectionTransferDragAdapter extends DragSourceAdapter implements TransferDragSourceListener {
  22
  23         private ISelectionProvider fProvider;
  24
  25         public BasicSelectionTransferDragAdapter(ISelectionProvider provider) {
  26                 Assert.isNotNull(provider);
  27                 fProvider= provider;
  28         }
  29
  30         /**
  31          * @see TransferDragSourceListener#getTransfer
  32          */
  33         public Transfer getTransfer() {
  34                 return LocalSelectionTransfer.getInstance();
  35         }
  36
  37         /* non Java-doc
  38          * @see org.eclipse.swt.dnd.DragSourceListener#dragStart
  39          */
  40         public void dragStart(DragSourceEvent event) {
  41                 ISelection selection= fProvider.getSelection();
  42                 LocalSelectionTransfer.getInstance().setSelection(selection);
  43                 LocalSelectionTransfer.getInstance().setSelectionSetTime(event.time);
  44                 event.doit= isDragable(selection);
  45         }
  46
  47         /**
  48          * Checks if the elements contained in the given selection can
  49          * be dragged.
  50          * <p>
  51          * Subclasses may override.
  52          *
  53          * @param selection containing the elements to be dragged
  54          */
  55         protected boolean isDragable(ISelection selection) {
  56                 return true;
  57         }
  58
  59
  60         /* non Java-doc
  61          * @see org.eclipse.swt.dnd.DragSourceListener#dragSetData
  62          */
  63         public void dragSetData(DragSourceEvent event) {
  64                 // For consistency set the data to the selection even though
  65                 // the selection is provided by the LocalSelectionTransfer
  66                 // to the drop target adapter.
  67                 event.data= LocalSelectionTransfer.getInstance().getSelection();
  68         }
  69
  70
  71         /* non Java-doc
  72          * @see org.eclipse.swt.dnd.DragSourceListener#dragFinished
  73          */
  74         public void dragFinished(DragSourceEvent event) {
  75                 // We assume that the drop target listener has done all
  76                 // the work.
  77                 Assert.isTrue(event.detail == DND.DROP_NONE);
  78                 LocalSelectionTransfer.getInstance().setSelection(null);
  79                 LocalSelectionTransfer.getInstance().setSelectionSetTime(0);
  80         }
  81 }