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Java > Open Source Codes > org > eclipse > jdt > internal > ui > typehierarchy > TypeHierarchyTransferDropAdapter


1 /*******************************************************************************
2  * Copyright (c) 2000, 2005 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  *******************************************************************************/
11 package org.eclipse.jdt.internal.ui.typehierarchy;
12
13 import org.eclipse.swt.dnd.DND;
14 import org.eclipse.swt.dnd.DropTargetEvent;
15
16 import org.eclipse.jface.viewers.AbstractTreeViewer;
17 import org.eclipse.jface.viewers.ISelection;
18
19 import org.eclipse.jdt.core.IJavaElement;
20
21 import org.eclipse.jdt.internal.ui.packageview.SelectionTransferDropAdapter;
22 import org.eclipse.jdt.internal.ui.util.OpenTypeHierarchyUtil;
23 import org.eclipse.jdt.internal.ui.util.SelectionUtil;
24
25 public class TypeHierarchyTransferDropAdapter extends SelectionTransferDropAdapter {
26
27     private static final int OPERATION = DND.DROP_LINK;
28     private TypeHierarchyViewPart fTypeHierarchyViewPart;
29
30     public TypeHierarchyTransferDropAdapter(TypeHierarchyViewPart viewPart, AbstractTreeViewer viewer) {
31         super(viewer);
32         setFullWidthMatchesItem(false);
33         fTypeHierarchyViewPart= viewPart;
34     }
35
36     public void validateDrop(Object JavaDoc target, DropTargetEvent event, int operation) {
37         event.detail= DND.DROP_NONE;
38         initializeSelection();
39         if (target != null){
40             super.validateDrop(target, event, operation);
41             return;
42         }
43         if (getInputElement(getSelection()) != null)
44             event.detail= TypeHierarchyTransferDropAdapter.OPERATION;
45     }
46         
47     /* (non-Javadoc)
48      * @see org.eclipse.jdt.internal.ui.packageview.SelectionTransferDropAdapter#isEnabled(org.eclipse.swt.dnd.DropTargetEvent)
49      */
50     public boolean isEnabled(DropTargetEvent event) {
51         return true;
52     }
53
54     public void drop(Object JavaDoc target, DropTargetEvent event) {
55         if (target != null || event.detail != TypeHierarchyTransferDropAdapter.OPERATION){
56             super.drop(target, event);
57             return;
58         }
59         IJavaElement input= getInputElement(getSelection());
60         fTypeHierarchyViewPart.setInputElement(input);
61     }
62     
63     private static IJavaElement getInputElement(ISelection selection) {
64         Object JavaDoc single= SelectionUtil.getSingleElement(selection);
65         if (single == null)
66             return null;
67         IJavaElement[] candidates= OpenTypeHierarchyUtil.getCandidates(single);
68         if (candidates != null && candidates.length > 0)
69             return candidates[0];
70         return null;
71     }
72 }
73
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