- /*
- * 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 1.4 2004/02/17 04:30:02 minchau 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.
- *
- * <p>Each method has the form
- * <code>boolean visitComponentType(ExpressionOwner owner, ComponentType compType)</code>.
- * 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.</p>
- *
- * <p>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.</p>
- */
- 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;
- }
-
-
- }
-