/*
* 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;
}
}