| /******************************************************************************* |
| * Copyright (c) 2002, 2005 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM - Initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.core.tools; |
| |
| import java.util.*; |
| import org.eclipse.jface.viewers.*; |
| |
| /** |
| * This class provides a decorator for ISelectionProviders that use |
| * TreeContentProviderNode as the basis for their data model. |
| * The only affected method is <code>getSelection()</code>, which will return a |
| * selection object that provides selected elements in the same order they |
| * appear in the tree. |
| * |
| * <p>This class is an workaround to the SWT's <code>Tree.getSelection()</code> |
| * method, which returns an array of selected elements without preserving the |
| * order they appear in the tree widget.</p> |
| */ |
| public class TreeSelectionProviderDecorator implements ISelectionProvider { |
| |
| /** The decorated selection provider. */ |
| private ISelectionProvider selectionProvider; |
| |
| /** |
| * Constructs a <code>TreeSelectionProviderDecorator</code> having the given |
| * selection provider as its decorated object. |
| * |
| * @param selectionProvider the selection provider to be decorated |
| */ |
| public TreeSelectionProviderDecorator(ISelectionProvider selectionProvider) { |
| this.selectionProvider = selectionProvider; |
| } |
| |
| /** |
| * @see org.eclipse.jface.viewers.ISelectionProvider#addSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener) |
| */ |
| public void addSelectionChangedListener(ISelectionChangedListener listener) { |
| selectionProvider.addSelectionChangedListener(listener); |
| } |
| |
| /** |
| * Returns the current selection for this provider. If the selection is a |
| * structured selection made of <code>TreeContentProviderNode</code> |
| * elements, this method will return a structured selection where the order of |
| * elements is the same order the elements appear in the tree (only for tree |
| * elements that are instances of <code>TreeContentProviderNode</code>). |
| * |
| * @return the current selection, ordered in the same sequence they appear in |
| * the tree |
| * @see org.eclipse.jface.viewers.ISelectionProvider#getSelection() |
| */ |
| public ISelection getSelection() { |
| // gets the original selection object |
| ISelection selection = selectionProvider.getSelection(); |
| |
| // in these cases the original selection will be returned |
| if (selection == null || selection.isEmpty() || !(selection instanceof IStructuredSelection)) |
| return selection; |
| |
| // constructs a list with the selected elements |
| IStructuredSelection structuredSelection = (IStructuredSelection) selection; |
| final List selectedElements = new ArrayList(structuredSelection.toList()); |
| |
| // tries to find a TreeContentProviderNode between the selected elements |
| TreeContentProviderNode anyNode = findNodeElement(selectedElements); |
| |
| // if there is no TreeContentProviderNodes, there is nothing to do |
| if (anyNode == null) |
| return selection; |
| |
| // otherwise, we will move the elements to a new list in the same order |
| // we find them in the tree. |
| final List orderedElements = new LinkedList(); |
| |
| // uses a visitor to traverse the whole tree |
| // when a visited node is the selected list, it is moved to the ordered list |
| anyNode.getRoot().accept(new ITreeNodeVisitor() { |
| public boolean visit(TreeContentProviderNode node) { |
| int elementIndex = selectedElements.indexOf(node); |
| |
| if (selectedElements.contains(node)) |
| orderedElements.add(selectedElements.remove(elementIndex)); |
| |
| return true; |
| } |
| }); |
| |
| // any remaining elements in the list (probably they are not tree nodes) |
| // are copied to the end of the ordered list |
| orderedElements.addAll(selectedElements); |
| return new StructuredSelection(orderedElements); |
| } |
| |
| /** |
| * Returns the first element in the list that is instance of |
| * <code>TreeContentProviderNode</code>. |
| * |
| * @return the first element that is a tree node or null, if none is found. |
| */ |
| private TreeContentProviderNode findNodeElement(List elements) { |
| for (Iterator iter = elements.iterator(); iter.hasNext();) { |
| Object element = iter.next(); |
| if (element instanceof TreeContentProviderNode) |
| return (TreeContentProviderNode) element; |
| } |
| |
| return null; |
| } |
| |
| /** |
| * @see org.eclipse.jface.viewers.ISelectionProvider#removeSelectionChangedListener(org.eclipse.jface.viewers.ISelectionChangedListener) |
| */ |
| public void removeSelectionChangedListener(ISelectionChangedListener listener) { |
| selectionProvider.removeSelectionChangedListener(listener); |
| } |
| |
| /** |
| * @see org.eclipse.jface.viewers.ISelectionProvider#setSelection(org.eclipse.jface.viewers.ISelection) |
| */ |
| public void setSelection(ISelection selection) { |
| selectionProvider.setSelection(selection); |
| } |
| |
| } |