MatchNodeVisitor.java

/*******************************************************************************
 * Copyright (c) 2009, 2011 Sierra Wireless 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:
 *     Sierra Wireless - initial API and implementation
 *     Kevin KIN-FOO <kkinfoo@sierrawireless.com>
 ******************************************************************************/
package org.eclipse.koneki.ldt.core.internal.ast.models;

import org.eclipse.dltk.ast.ASTNode;
import org.eclipse.dltk.ast.ASTVisitor;

/**
 * Visits ASTs in order to find node under start and end offsets.
 */
public class MatchNodeVisitor extends ASTVisitor {
	private final int end;
	private final int start;
	private ASTNode result;
	private Class<?> clazz;

	/**
	 * Constructor initialized with offsets to seek for
	 * 
	 * @param start
	 *            offset
	 * @param end
	 *            offset
	 */
	public MatchNodeVisitor(int start, int end, Class<?> clazz) {
		this.end = end;
		this.start = start;
		this.clazz = clazz;
	}

	/**
	 * Retrieve matching node, available after using current object in {@link ASTNode#traverse(ASTVisitor)}
	 * 
	 * @return matching {@link ASTNode} or null if not available
	 */
	public ASTNode getNode() {
		return result;
	}

	protected void setNode(ASTNode node) {
		result = node;
	}

	/**
	 * Browse given {@link ASTNode} tree to found a node matching offset provided in {@link #MatchNodeVisitor(int, int)}
	 * 
	 * @see ASTVisitor#visitGeneral(ASTNode)
	 * @see #MatchNodeVisitor(int, int)
	 */
	public boolean visitGeneral(ASTNode s) throws Exception {
		int realStart = s.sourceStart();
		int realEnd = s.sourceEnd();
		if (realStart <= start && realEnd >= end) {
			if (clazz.isInstance(s)) {
				if (getNode() == null) {
					setNode(s);
				} else if (s.sourceStart() >= getNode().sourceStart() && s.sourceEnd() <= getNode().sourceEnd()) {
					setNode(s);
				}
			}
			return true;
		} else {
			return false;
		}

	}
}