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
  22                 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         /*
  39          * non Java-doc
  40          *
  41          * @see org.eclipse.swt.dnd.DragSourceListener#dragStart
  42          */
  43         public void dragStart(DragSourceEvent event) {
  44                 ISelection selection = fProvider.getSelection();
  45                 LocalSelectionTransfer.getInstance().setSelection(selection);
  46                 LocalSelectionTransfer.getInstance().setSelectionSetTime(event.time);
  47                 event.doit = isDragable(selection);
  48         }
  49
  50         /**
  51          * Checks if the elements contained in the given selection can be dragged.
  52          * <p>
  53          * Subclasses may override.
  54          *
  55          * @param selection
  56          *            containing the elements to be dragged
  57          */
  58         protected boolean isDragable(ISelection selection) {
  59                 return true;
  60         }
  61
  62         /*
  63          * non Java-doc
  64          *
  65          * @see org.eclipse.swt.dnd.DragSourceListener#dragSetData
  66          */
  67         public void dragSetData(DragSourceEvent event) {
  68                 // For consistency set the data to the selection even though
  69                 // the selection is provided by the LocalSelectionTransfer
  70                 // to the drop target adapter.
  71                 event.data = LocalSelectionTransfer.getInstance().getSelection();
  72         }
  73
  74         /*
  75          * non Java-doc
  76          *
  77          * @see org.eclipse.swt.dnd.DragSourceListener#dragFinished
  78          */
  79         public void dragFinished(DragSourceEvent event) {
  80                 // We assume that the drop target listener has done all
  81                 // the work.
  82                 Assert.isTrue(event.detail == DND.DROP_NONE);
  83                 LocalSelectionTransfer.getInstance().setSelection(null);
  84                 LocalSelectionTransfer.getInstance().setSelectionSetTime(0);
  85         }
  86 }