code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you 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.
   */
  /*
   * $Id$
   */
  package org.apache.xalan.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.
  	 */
  	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.
  	 */
  	public boolean visitVariableRef(ExpressionOwner owner, Variable var)
  	{
  		m_isAbs = false;
  		return true;
  	}
  }
  
  