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.swt.dnd.DND;
  14 import org.eclipse.swt.dnd.DragSourceAdapter;
  15 import org.eclipse.swt.dnd.DragSourceEvent;
  16 import org.eclipse.swt.dnd.Transfer;
  17
  18 import org.eclipse.jface.util.Assert;
  19 import org.eclipse.jface.viewers.ISelection;
  20 import org.eclipse.jface.viewers.ISelectionProvider;
  21
  22 public class BasicSelectionTransferDragAdapter extends DragSourceAdapter implements TransferDragSourceListener {
  23
  24         private ISelectionProvider fProvider;
  25
  26         public BasicSelectionTransferDragAdapter(ISelectionProvider provider) {
  27                 Assert.isNotNull(provider);
  28                 fProvider= provider;
  29         }
  30
  31         /**
  32          * @see TransferDragSourceListener#getTransfer
  33          */
  34         public Transfer getTransfer() {
  35                 return LocalSelectionTransfer.getInstance();
  36         }
  37
  38         /* non Java-doc
  39          * @see org.eclipse.swt.dnd.DragSourceListener#dragStart
  40          */
  41         public void dragStart(DragSourceEvent event) {
  42                 ISelection selection= fProvider.getSelection();
  43                 LocalSelectionTransfer.getInstance().setSelection(selection);
  44                 LocalSelectionTransfer.getInstance().setSelectionSetTime(event.time);
  45                 event.doit= isDragable(selection);
  46         }
  47
  48         /**
  49          * Checks if the elements contained in the given selection can
  50          * be dragged.
  51          * <p>
  52          * Subclasses may override.
  53          *
  54          * @param selection containing the elements to be dragged
  55          */
  56         protected boolean isDragable(ISelection selection) {
  57                 return true;
  58         }
  59
  60
  61         /* non Java-doc
  62          * @see org.eclipse.swt.dnd.DragSourceListener#dragSetData
  63          */
  64         public void dragSetData(DragSourceEvent event) {
  65                 // For consistency set the data to the selection even though
  66                 // the selection is provided by the LocalSelectionTransfer
  67                 // to the drop target adapter.
  68                 event.data= LocalSelectionTransfer.getInstance().getSelection();
  69         }
  70
  71
  72         /* non Java-doc
  73          * @see org.eclipse.swt.dnd.DragSourceListener#dragFinished
  74          */
  75         public void dragFinished(DragSourceEvent event) {
  76                 // We assume that the drop target listener has done all
  77                 // the work.
  78                 Assert.isTrue(event.detail == DND.DROP_NONE);
  79                 LocalSelectionTransfer.getInstance().setSelection(null);
  80                 LocalSelectionTransfer.getInstance().setSelectionSetTime(0);
  81         }
  82 }