net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/dnd/JdtViewerDragAdapter.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.IStructuredSelection;
  15 import org.eclipse.jface.viewers.StructuredViewer;
  16 import org.eclipse.swt.dnd.DragSourceEvent;
  17
  18 public class JdtViewerDragAdapter extends DelegatingDragAdapter {
  19
  20         private StructuredViewer fViewer;
  21
  22         public JdtViewerDragAdapter(StructuredViewer viewer,
  23                         TransferDragSourceListener[] listeners) {
  24                 super(listeners);
  25                 Assert.isNotNull(viewer);
  26                 fViewer = viewer;
  27         }
  28
  29         public void dragStart(DragSourceEvent event) {
  30                 IStructuredSelection selection = (IStructuredSelection) fViewer
  31                                 .getSelection();
  32                 if (selection.isEmpty()) {
  33                         event.doit = false;
  34                         return;
  35                 }
  36                 super.dragStart(event);
  37         }
  38 }