/*=============================================================================#
# Copyright (c) 2007-2016 Stephan Wahlbrink (WalWare.de) 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:
# Stephan Wahlbrink - initial API and implementation
#=============================================================================*/
package de.walware.ecommons.ltk.ui.sourceediting;
import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.jface.text.IRegion;
import org.eclipse.ui.texteditor.IUpdate;
/**
* Action to restore the last structure selection.
*
* @see StructureSelectHandler
*/
public class StructureSelectionHistoryBackHandler extends AbstractHandler implements IUpdate {
private final ISourceEditor fSourceEditor;
private final StructureSelectionHistory fHistory;
public StructureSelectionHistoryBackHandler(final ISourceEditor editor, final StructureSelectionHistory history) {
super();
assert (editor != null);
assert (history != null);
fSourceEditor = editor;
fHistory = history;
update();
}
@Override
public void update() {
setBaseEnabled(!fHistory.isEmpty());
}
@Override
public Object execute(final ExecutionEvent event) throws ExecutionException {
final IRegion old = fHistory.getLast();
if (old != null) {
try {
fHistory.ignoreSelectionChanges();
fSourceEditor.selectAndReveal(old.getOffset(), old.getLength());
}
finally {
fHistory.listenToSelectionChanges();
}
}
return null;
}
}