19f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson/* 29f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Licensed to the Apache Software Foundation (ASF) under one 39f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * or more contributor license agreements. See the NOTICE file 49f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * distributed with this work for additional information 59f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * regarding copyright ownership. The ASF licenses this file 69f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * to you under the Apache License, Version 2.0 (the "License"); 79f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * you may not use this file except in compliance with the License. 89f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * You may obtain a copy of the License at 99f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 109f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * http://www.apache.org/licenses/LICENSE-2.0 119f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 129f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Unless required by applicable law or agreed to in writing, software 139f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * distributed under the License is distributed on an "AS IS" BASIS, 149f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 159f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * See the License for the specific language governing permissions and 169f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * limitations under the License. 179f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 189f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson/* 199f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * $Id: XPathVisitor.java 468655 2006-10-28 07:12:06Z minchau $ 209f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 219f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonpackage org.apache.xpath; 229f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 239f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.axes.LocPathIterator; 249f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.axes.UnionPathIterator; 259f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.functions.Function; 269f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.objects.XNumber; 279f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.objects.XString; 289f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.operations.Operation; 299f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.operations.UnaryOperation; 309f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.operations.Variable; 319f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.patterns.NodeTest; 329f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.patterns.StepPattern; 339f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonimport org.apache.xpath.patterns.UnionPattern; 349f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 359f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson/** 369f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * A derivation from this class can be passed to a class that implements 379f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * the XPathVisitable interface, to have the appropriate method called 389f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * for each component of the XPath. Aside from possible other uses, the 399f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * main intention is to provide a reasonable means to perform expression 409f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * rewriting. 419f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 429f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * <p>Each method has the form 439f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * <code>boolean visitComponentType(ExpressionOwner owner, ComponentType compType)</code>. 449f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * The ExpressionOwner argument is the owner of the component, and can 459f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be used to reset the expression for rewriting. If a method returns 469f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * false, the sub hierarchy will not be traversed.</p> 479f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 489f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * <p>This class is meant to be a base class that will be derived by concrete classes, 499f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * and doesn't much except return true for each method.</p> 509f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 519f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilsonpublic class XPathVisitor 529f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson{ 539f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 549f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a LocationPath. 559f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 569f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 579f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param path The LocationPath object. 589f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 599f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 609f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitLocationPath(ExpressionOwner owner, LocPathIterator path) 619f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 629f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 639f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 649f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 659f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 669f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a UnionPath. 679f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 689f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 699f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param path The UnionPath object. 709f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 719f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 729f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitUnionPath(ExpressionOwner owner, UnionPathIterator path) 739f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 749f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 759f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 769f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 779f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 789f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a step within a location path. 799f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 809f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 819f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param step The Step object. 829f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 839f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 849f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitStep(ExpressionOwner owner, NodeTest step) 859f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 869f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 879f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 889f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 899f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 909f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a predicate within a location path. Note that there isn't a 919f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * proper unique component for predicates, and that the expression will 929f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be called also for whatever type Expression is. 939f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * 949f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 959f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 969f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param pred The predicate object. 979f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 989f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 999f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitPredicate(ExpressionOwner owner, Expression pred) 1009f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1019f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 1029f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1039f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1049f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1059f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a binary operation. 1069f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 1079f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 1089f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param op The operation object. 1099f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 1109f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1119f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitBinaryOperation(ExpressionOwner owner, Operation op) 1129f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1139f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 1149f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1159f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1169f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1179f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a unary operation. 1189f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 1199f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 1209f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param op The operation object. 1219f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 1229f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1239f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitUnaryOperation(ExpressionOwner owner, UnaryOperation op) 1249f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1259f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 1269f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1279f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1289f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1299f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a variable reference. 1309f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 1319f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 1329f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param var The variable reference object. 1339f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 1349f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1359f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitVariableRef(ExpressionOwner owner, Variable var) 1369f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1379f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 1389f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1399f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1409f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1419f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a function. 1429f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 1439f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 1449f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param func The function reference object. 1459f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 1469f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1479f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitFunction(ExpressionOwner owner, Function func) 1489f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1499f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 1509f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1519f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1529f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1539f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a match pattern. 1549f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 1559f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 1569f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param pattern The match pattern object. 1579f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 1589f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1599f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitMatchPattern(ExpressionOwner owner, StepPattern pattern) 1609f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1619f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 1629f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1639f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1649f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1659f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a union pattern. 1669f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 1679f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 1689f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param pattern The union pattern object. 1699f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 1709f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1719f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitUnionPattern(ExpressionOwner owner, UnionPattern pattern) 1729f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1739f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 1749f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1759f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1769f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1779f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a string literal. 1789f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 1799f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 1809f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param str The string literal object. 1819f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 1829f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1839f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitStringLiteral(ExpressionOwner owner, XString str) 1849f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1859f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 1869f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 1879f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1889f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 1899f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson /** 1909f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * Visit a number literal. 1919f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param owner The owner of the expression, to which the expression can 1929f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * be reset if rewriting takes place. 1939f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @param num The number literal object. 1949f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson * @return true if the sub expressions should be traversed. 1959f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson */ 1969f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson public boolean visitNumberLiteral(ExpressionOwner owner, XNumber num) 1979f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson { 1989f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson return true; 1999f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson } 2009f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 2019f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 2029f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson} 2039f8118474e9513f7a5b7d2a05e4a0fb15d1a6569Jesse Wilson 204