bundles/org.eclipse.wst.xsl.core/src_validation/org/eclipse/wst/xsl/core/internal/compiler/xslt10/templates/AbsPathChecker.java

/*******************************************************************************
 * Copyright (c) 2008 Standards for Technology in Automotive Retail
 * 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:
 *     David Carver - STAR - bug 224197 - initial API and implementation
 *                    based on work from Apache Xalan 2.7.0
 *******************************************************************************/

/*
 * Copyright 2002-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: AbsPathChecker.java,v 1.2 2008/03/28 02:38:15 dacarver Exp $
 */
package org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates;

import org.apache.xpath.ExpressionOwner;
import org.apache.xpath.XPathVisitor;
import org.apache.xpath.axes.LocPathIterator;
import org.apache.xpath.functions.FuncCurrent;
import org.apache.xpath.functions.FuncExtFunction;
import org.apache.xpath.functions.Function;
import org.apache.xpath.operations.Variable;

/**
 * This class runs over a path expression that is assumed to be absolute, and
 * checks for variables and the like that may make it context dependent.
 */
public class AbsPathChecker extends XPathVisitor {
	private boolean m_isAbs = true;

	/**
	 * Process the LocPathIterator to see if it contains variables or functions
	 * that may make it context dependent.
	 * 
	 * @param path
	 *            LocPathIterator that is assumed to be absolute, but needs
	 *            checking.
	 * @return true if the path is confirmed to be absolute, false if it may
	 *         contain context dependencies.
	 */
	public boolean checkAbsolute(LocPathIterator path) {
		m_isAbs = true;
		path.callVisitors(null, this);
		return m_isAbs;
	}

	/**
	 * Visit a function.
	 * 
	 * @param owner
	 *            The owner of the expression, to which the expression can be
	 *            reset if rewriting takes place.
	 * @param func
	 *            The function reference object.
	 * @return true if the sub expressions should be traversed.
	 */
	@Override
	public boolean visitFunction(ExpressionOwner owner, Function func) {
		if ((func instanceof FuncCurrent) || (func instanceof FuncExtFunction))
			m_isAbs = false;
		return true;
	}

	/**
	 * Visit a variable reference.
	 * 
	 * @param owner
	 *            The owner of the expression, to which the expression can be
	 *            reset if rewriting takes place.
	 * @param var
	 *            The variable reference object.
	 * @return true if the sub expressions should be traversed.
	 */
	@Override
	public boolean visitVariableRef(ExpressionOwner owner, Variable var) {
		m_isAbs = false;
		return true;
	}
}