| /******************************************************************************* |
| * Copyright (c) 2004, 2008 Tasktop Technologies 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: |
| * Tasktop Technologies - initial API and implementation |
| *******************************************************************************/ |
| |
| package org.eclipse.mylyn.internal.tasks.ui.util; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collections; |
| import java.util.List; |
| |
| import org.eclipse.jface.viewers.TreePath; |
| import org.eclipse.jface.viewers.TreeViewer; |
| import org.eclipse.swt.widgets.Tree; |
| import org.eclipse.swt.widgets.TreeItem; |
| |
| /** |
| * @author Steffen Pingel |
| */ |
| public class TreeWalker { |
| |
| public enum Direction { |
| UP, DOWN |
| }; |
| |
| public static abstract class TreeVisitor { |
| |
| public abstract boolean visit(Object object); |
| |
| } |
| |
| private Direction direction = Direction.DOWN; |
| |
| private final TreeViewer treeViewer; |
| |
| private final Tree tree; |
| |
| private boolean expandNodes; |
| |
| public TreeWalker(TreeViewer treeViewer) { |
| this.treeViewer = treeViewer; |
| this.tree = treeViewer.getTree(); |
| } |
| |
| public Direction getDirection() { |
| return direction; |
| } |
| |
| public boolean getExpandNodes() { |
| return expandNodes; |
| } |
| |
| private TreePath getTreePath(TreeItem item) { |
| List<Object> path = new ArrayList<Object>(); |
| do { |
| // the tree is probably not fully refreshed at this point |
| if (item.getData() == null) { |
| return null; |
| } |
| path.add(0, item.getData()); |
| item = item.getParentItem(); |
| } while (item != null); |
| return new TreePath(path.toArray()); |
| } |
| |
| public void setDirection(Direction direction) { |
| this.direction = direction; |
| } |
| |
| public void setExpandNodes(boolean expandNodes) { |
| this.expandNodes = expandNodes; |
| } |
| |
| private TreePath visitChildren(TreeViewer viewer, TreePath itemPath, TreeItem item, TreeVisitor visitor) { |
| boolean restoreCollapsedState = false; |
| // expand item |
| try { |
| if (getExpandNodes()) { |
| boolean expandedState = item.getExpanded(); |
| if (!expandedState) { |
| restoreCollapsedState = true; |
| viewer.setExpandedState(itemPath, true); |
| } |
| } |
| |
| TreeItem[] children = item.getItems(); |
| if (children.length > 0 && children[0].getData() != null) { |
| TreePath childPath = visitItems(viewer, itemPath, children, null, visitor); |
| if (childPath != null) { |
| return childPath; |
| } |
| } |
| |
| } finally { |
| if (restoreCollapsedState) { |
| // restore item state |
| viewer.setExpandedState(itemPath, false); |
| } |
| } |
| |
| return null; |
| } |
| |
| private TreePath visitItems(TreeViewer viewer, TreePath parentPath, TreeItem[] items, TreeItem visitedItem, |
| TreeVisitor visitor) { |
| if (direction == Direction.UP) { |
| Collections.reverse(Arrays.asList(items)); |
| } |
| |
| boolean found = (visitedItem == null); |
| for (TreeItem item : items) { |
| if (!found) { |
| if (item == visitedItem) { |
| found = true; |
| } |
| } else { |
| TreePath itemPath = parentPath.createChildPath(item.getData()); |
| |
| if (direction == Direction.DOWN) { |
| if (visitor.visit(item.getData())) { |
| return itemPath; |
| } |
| } |
| |
| TreePath childPath = visitChildren(viewer, itemPath, item, visitor); |
| if (childPath != null) { |
| return childPath; |
| } |
| |
| if (direction == Direction.UP) { |
| if (visitor.visit(item.getData())) { |
| return itemPath; |
| } |
| } |
| } |
| } |
| |
| // visit parent siblings |
| if (visitedItem != null) { |
| TreeItem parent = visitedItem.getParentItem(); |
| if (parent != null) { |
| if (direction == Direction.UP) { |
| if (visitor.visit(parent.getData())) { |
| return parentPath; |
| } |
| } |
| |
| return visitSiblings(viewer, parent, visitor); |
| } |
| } |
| |
| return null; |
| } |
| |
| private TreePath visitSiblings(TreeViewer viewer, TreeItem item, TreeVisitor visitor) { |
| TreeItem[] siblings; |
| TreePath path; |
| TreeItem parent = item.getParentItem(); |
| if (parent != null) { |
| path = getTreePath(parent); |
| if (path == null) { |
| return null; |
| } |
| siblings = parent.getItems(); |
| } else { |
| path = TreePath.EMPTY; |
| siblings = viewer.getTree().getItems(); |
| } |
| return visitItems(viewer, path, siblings, item, visitor); |
| } |
| |
| public TreePath walk(TreeVisitor visitor, TreeItem startItem) { |
| TreePath path = null; |
| if (startItem != null) { |
| if (direction == Direction.DOWN) { |
| path = getTreePath(startItem); |
| if (path != null) { |
| path = visitChildren(treeViewer, path, startItem, visitor); |
| } |
| } |
| if (path == null) { |
| path = visitSiblings(treeViewer, startItem, visitor); |
| } |
| } else { |
| path = visitItems(treeViewer, TreePath.EMPTY, tree.getItems(), null, visitor); |
| } |
| |
| return path; |
| } |
| |
| } |