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- /* *******************************************************************
- * Copyright (c) 1999-2001 Xerox Corporation,
- * 2002 Palo Alto Research Center, Incorporated (PARC).
- * All rights reserved.
- * This program and the accompanying materials are made available
- * under the terms of the Eclipse Public License v 2.0
- * which accompanies this distribution and is available at
- * https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.txt
- *
- * Contributors:
- * Xerox/PARC initial implementation
- * ******************************************************************/
-
-
- package org.aspectj.ajde.ui.internal;
-
- import java.util.Stack;
-
- import org.aspectj.asm.IProgramElement;
-
- /**
- * @author Mik Kersten
- */
- public class NavigationHistoryModel {
-
- private IProgramElement currNode = null;
- private Stack backHistory = new Stack();
- private Stack forwardHistory = new Stack();
-
- /**
- * @return null if the history is empty
- */
- public IProgramElement navigateBack() {
- if (backHistory.isEmpty() || currNode == null) return null;
-
- forwardHistory.push(currNode);
- currNode = (IProgramElement)backHistory.pop();
- return currNode;
- }
-
- /**
- * @return null if the history is empty
- */
- public IProgramElement navigateForward() {
- if (forwardHistory.isEmpty() || currNode == null) return null;
-
- backHistory.push(currNode);
- currNode = (IProgramElement)forwardHistory.pop();
- return currNode;
- }
-
-
- public void navigateToNode(IProgramElement toNode) {
- if (currNode != null) backHistory.push(currNode);
- currNode = toNode;
- }
- }
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