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/**********************************************************************
* Copyright (c) 2004, 2005 QNX Software Systems 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:
* QNX Software Systems - Initial API and implementation
***********************************************************************/
package org.eclipse.debug.internal.ui.views;
import java.util.ArrayList;
import java.util.List;
import org.eclipse.core.runtime.IPath;
import org.eclipse.debug.core.DebugException;
import org.eclipse.debug.internal.ui.views.variables.VariablesViewer;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.swt.widgets.TreeItem;
/**
* The abstract superclass for mementos of the expanded and
* selected items in a tree viewer.
*/
public abstract class AbstractViewerState {
// paths to expanded elements
protected List fSavedExpansion = null;
protected IPath[] fSelection;
/**
* Constructs a memento for the given viewer.
*/
public AbstractViewerState(TreeViewer viewer) {
saveState(viewer);
}
public AbstractViewerState() {
}
/**
* Saves the current state of the given viewer into
* this memento.
*
* @param viewer viewer of which to save the state
*/
public void saveState(TreeViewer viewer) {
List expanded = new ArrayList();
fSavedExpansion = null;
TreeItem[] items = viewer.getTree().getItems();
try {
for (int i = 0; i < items.length; i++) {
collectExpandedItems(items[i], expanded);
}
if (expanded.size() > 0) {
fSavedExpansion = expanded;
}
} catch (DebugException e) {
fSavedExpansion = null;
}
TreeItem[] selection = viewer.getTree().getSelection();
fSelection = new IPath[selection.length];
try {
for (int i = 0; i < selection.length; i++) {
fSelection[i] = encodeElement(selection[i]);
if (fSelection[i] == null) {
fSelection = null;
return;
}
}
} catch (DebugException e) {
fSelection = null;
}
}
protected void collectExpandedItems(TreeItem item, List expanded) throws DebugException {
if (item.getExpanded()) {
IPath path = encodeElement(item);
if (path != null) {
expanded.add(path);
TreeItem[] items = item.getItems();
for (int i = 0; i < items.length; i++) {
collectExpandedItems(items[i], expanded);
}
}
}
}
/**
* Constructs a path representing the given tree item. The segments in the
* path denote parent items, and the last segment is the name of
* the given item.
*
* @param item tree item to encode
* @return path encoding the given item
* @throws DebugException if unable to generate a path
*/
protected abstract IPath encodeElement(TreeItem item) throws DebugException;
/**
* Restores the state of the given viewer to this memento's
* saved state.
*
* @param viewer viewer to which state is restored
*/
public void restoreState(TreeViewer viewer) {
boolean expansionComplete = true;
if (fSavedExpansion != null && fSavedExpansion.size() > 0) {
for (int i = 0; i < fSavedExpansion.size(); i++) {
IPath path = (IPath) fSavedExpansion.get(i);
if (path != null) {
if (viewer instanceof VariablesViewer) {
VariablesViewer variablesViewer = (VariablesViewer) viewer;
boolean complete = variablesViewer.expandPath(path);
if (!complete)
expansionComplete = false;
} else {
Object obj;
try {
obj = decodePath(path, viewer);
if (obj != null) {
viewer.expandToLevel(obj, 1);
} else {
expansionComplete = false;
}
} catch (DebugException e) {
}
}
}
}
if (expansionComplete) {
fSavedExpansion = null;
}
}
boolean selectionComplete = true;
if (fSelection != null && fSelection.length > 0) {
List selection = new ArrayList(fSelection.length);
for (int i = 0; i < fSelection.length; i++) {
IPath path = fSelection[i];
Object obj;
try {
obj = decodePath(path, viewer);
if (obj != null) {
selection.add(obj);
} else {
selectionComplete = false;
}
} catch (DebugException e) {
}
}
if (selection.size() > 0) {
viewer.setSelection(new StructuredSelection(selection));
}
if (selectionComplete) {
fSelection = null;
}
}
}
/**
* Returns an element in the given viewer that corresponds to the given
* path, or <code>null</code> if none.
*
* @param path encoded element path
* @param viewer viewer to search for the element in
* @return element represented by the path, or <code>null</code> if none
* @throws DebugException if unable to locate a variable
*/
protected abstract Object decodePath(IPath path, TreeViewer viewer) throws DebugException;
public abstract AbstractViewerState copy();
}
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