/* * reserved comment block * DO NOT REMOVE OR ALTER! */ /* * Copyright 2002-2004 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: XPathVisitor.java,v 1.1.2.1 2005/08/01 01:30:11 jeffsuttor Exp $ */ package com.sun.org.apache.xpath.internal; import com.sun.org.apache.xpath.internal.axes.LocPathIterator; import com.sun.org.apache.xpath.internal.axes.UnionPathIterator; 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.objects.XString; import com.sun.org.apache.xpath.internal.operations.Operation; import com.sun.org.apache.xpath.internal.operations.UnaryOperation; import com.sun.org.apache.xpath.internal.operations.Variable; import com.sun.org.apache.xpath.internal.patterns.NodeTest; import com.sun.org.apache.xpath.internal.patterns.StepPattern; import com.sun.org.apache.xpath.internal.patterns.UnionPattern; /** * A derivation from this class can be passed to a class that implements * the XPathVisitable interface, to have the appropriate method called * for each component of the XPath. Aside from possible other uses, the * main intention is to provide a reasonable means to perform expression * rewriting. * *

Each method has the form * boolean visitComponentType(ExpressionOwner owner, ComponentType compType). * The ExpressionOwner argument is the owner of the component, and can * be used to reset the expression for rewriting. If a method returns * false, the sub hierarchy will not be traversed.

* *

This class is meant to be a base class that will be derived by concrete classes, * and doesn't much except return true for each method.

*/ public class XPathVisitor { /** * Visit a LocationPath. * @param owner The owner of the expression, to which the expression can * be reset if rewriting takes place. * @param path The LocationPath object. * @return true if the sub expressions should be traversed. */ public boolean visitLocationPath(ExpressionOwner owner, LocPathIterator path) { return true; } /** * Visit a UnionPath. * @param owner The owner of the expression, to which the expression can * be reset if rewriting takes place. * @param path The UnionPath object. * @return true if the sub expressions should be traversed. */ public boolean visitUnionPath(ExpressionOwner owner, UnionPathIterator path) { return true; } /** * Visit a step within a location path. * @param owner The owner of the expression, to which the expression can * be reset if rewriting takes place. * @param step The Step object. * @return true if the sub expressions should be traversed. */ public boolean visitStep(ExpressionOwner owner, NodeTest step) { 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) { return true; } /** * Visit a binary operation. * @param owner The owner of the expression, to which the expression can * be reset if rewriting takes place. * @param op The operation object. * @return true if the sub expressions should be traversed. */ public boolean visitBinaryOperation(ExpressionOwner owner, Operation op) { return true; } /** * Visit a unary operation. * @param owner The owner of the expression, to which the expression can * be reset if rewriting takes place. * @param op The operation object. * @return true if the sub expressions should be traversed. */ public boolean visitUnaryOperation(ExpressionOwner owner, UnaryOperation op) { 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) { return true; } /** * 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) { return true; } /** * Visit a match pattern. * @param owner The owner of the expression, to which the expression can * be reset if rewriting takes place. * @param pattern The match pattern object. * @return true if the sub expressions should be traversed. */ public boolean visitMatchPattern(ExpressionOwner owner, StepPattern pattern) { return true; } /** * Visit a union pattern. * @param owner The owner of the expression, to which the expression can * be reset if rewriting takes place. * @param pattern The union pattern object. * @return true if the sub expressions should be traversed. */ public boolean visitUnionPattern(ExpressionOwner owner, UnionPattern pattern) { return true; } /** * Visit a string literal. * @param owner The owner of the expression, to which the expression can * be reset if rewriting takes place. * @param str The string literal object. * @return true if the sub expressions should be traversed. */ public boolean visitStringLiteral(ExpressionOwner owner, XString str) { return true; } /** * Visit a number literal. * @param owner The owner of the expression, to which the expression can * be reset if rewriting takes place. * @param num The number literal object. * @return true if the sub expressions should be traversed. */ public boolean visitNumberLiteral(ExpressionOwner owner, XNumber num) { return true; } }