/* * reserved comment block * DO NOT REMOVE OR ALTER! */ /* * Copyright 1999-2004 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: HasPositionalPredChecker.java,v 1.1.2.1 2005/08/01 01:30:24 jeffsuttor Exp $ */ package com.sun.org.apache.xpath.internal.axes; import com.sun.org.apache.xpath.internal.Expression; import com.sun.org.apache.xpath.internal.ExpressionOwner; import com.sun.org.apache.xpath.internal.XPathVisitor; import com.sun.org.apache.xpath.internal.functions.FuncLast; import com.sun.org.apache.xpath.internal.functions.FuncPosition; import com.sun.org.apache.xpath.internal.functions.Function; import com.sun.org.apache.xpath.internal.objects.XNumber; import com.sun.org.apache.xpath.internal.operations.Div; import com.sun.org.apache.xpath.internal.operations.Minus; import com.sun.org.apache.xpath.internal.operations.Mod; import com.sun.org.apache.xpath.internal.operations.Mult; import com.sun.org.apache.xpath.internal.operations.Plus; import com.sun.org.apache.xpath.internal.operations.Quo; import com.sun.org.apache.xpath.internal.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 com.sun.org.apache.xpath.internal.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; } }