/*
 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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
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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;

@SuppressWarnings("deprecation")
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.
Params:
  • path – LocPathIterator that is assumed to be absolute, but needs checking.
Returns:true if the path is confirmed to be absolute, false if it may contain context dependencies.
/** * 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.
Params:
  • owner – The owner of the expression, to which the expression can be reset if rewriting takes place.
  • func – The function reference object.
Returns:true if the sub expressions should be traversed.
/** * 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.
Params:
  • owner – The owner of the expression, to which the expression can be reset if rewriting takes place.
  • pred – The predicate object.
Returns:true if the sub expressions should be traversed.
/** * 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; } }