| /* |
| * 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: HasPositionalPredChecker.java 468655 2006-10-28 07:12:06Z minchau $ |
| */ |
| package org.apache.xpath.axes; |
| |
| import org.apache.xpath.Expression; |
| import org.apache.xpath.ExpressionOwner; |
| import org.apache.xpath.XPathVisitor; |
| import org.apache.xpath.functions.FuncLast; |
| import org.apache.xpath.functions.FuncPosition; |
| import org.apache.xpath.functions.Function; |
| import org.apache.xpath.objects.XNumber; |
| import org.apache.xpath.operations.Div; |
| import org.apache.xpath.operations.Minus; |
| import org.apache.xpath.operations.Mod; |
| import org.apache.xpath.operations.Mult; |
| import org.apache.xpath.operations.Plus; |
| import org.apache.xpath.operations.Quo; |
| import org.apache.xpath.operations.Variable; |
| |
| public class HasPositionalPredChecker extends XPathVisitor |
| { |
| private boolean m_hasPositionalPred = false; |
| private int m_predDepth = 0; |
| |
| /** |
| * 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 static boolean check(LocPathIterator path) |
| { |
| HasPositionalPredChecker hppc = new HasPositionalPredChecker(); |
| path.callVisitors(null, hppc); |
| return hppc.m_hasPositionalPred; |
| } |
| |
| /** |
| * 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 FuncPosition) || |
| (func instanceof FuncLast)) |
| m_hasPositionalPred = true; |
| 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_hasPositionalPred = true; |
| // return true; |
| // } |
| |
| /** |
| * Visit a predicate within a location path. Note that there isn't a |
| * proper unique component for predicates, and that the expression will |
| * be called also for whatever type Expression is. |
| * |
| * @param owner The owner of the expression, to which the expression can |
| * be reset if rewriting takes place. |
| * @param pred The predicate object. |
| * @return true if the sub expressions should be traversed. |
| */ |
| public boolean visitPredicate(ExpressionOwner owner, Expression pred) |
| { |
| m_predDepth++; |
| |
| if(m_predDepth == 1) |
| { |
| if((pred instanceof Variable) || |
| (pred instanceof XNumber) || |
| (pred instanceof Div) || |
| (pred instanceof Plus) || |
| (pred instanceof Minus) || |
| (pred instanceof Mod) || |
| (pred instanceof Quo) || |
| (pred instanceof Mult) || |
| (pred instanceof org.apache.xpath.operations.Number) || |
| (pred instanceof Function)) |
| m_hasPositionalPred = true; |
| else |
| pred.callVisitors(owner, this); |
| } |
| |
| m_predDepth--; |
| |
| // Don't go have the caller go any further down the subtree. |
| return false; |
| } |
| |
| |
| } |
| |