1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 /* 19 * $Id: ExpressionVisitor.java 468637 2006-10-28 06:51:02Z minchau $ 20 */ 21 package org.apache.xalan.extensions; 22 23 import org.apache.xalan.templates.StylesheetRoot; 24 import org.apache.xpath.ExpressionOwner; 25 import org.apache.xpath.XPathVisitor; 26 import org.apache.xpath.functions.FuncExtFunction; 27 import org.apache.xpath.functions.FuncExtFunctionAvailable; 28 import org.apache.xpath.functions.Function; 29 30 /** 31 * When {@link org.apache.xalan.processor.StylesheetHandler} creates 32 * an {@link org.apache.xpath.XPath}, the ExpressionVisitor 33 * visits the XPath expression. For any extension functions it 34 * encounters, it instructs StylesheetRoot to register the 35 * extension namespace. 36 * 37 * This mechanism is required to locate extension functions 38 * that may be embedded within an expression. 39 */ 40 public class ExpressionVisitor extends XPathVisitor 41 { 42 private StylesheetRoot m_sroot; 43 44 /** 45 * The constructor sets the StylesheetRoot variable which 46 * is used to register extension namespaces. 47 * @param sroot the StylesheetRoot that is being constructed. 48 */ 49 public ExpressionVisitor (StylesheetRoot sroot) 50 { 51 m_sroot = sroot; 52 } 53 54 /** 55 * If the function is an extension function, register the namespace. 56 * 57 * @param owner The current XPath object that owns the expression. 58 * @param func The function currently being visited. 59 * 60 * @return true to continue the visit in the subtree, if any. 61 */ 62 public boolean visitFunction(ExpressionOwner owner, Function func) 63 { 64 if (func instanceof FuncExtFunction) 65 { 66 String namespace = ((FuncExtFunction)func).getNamespace(); 67 m_sroot.getExtensionNamespacesManager().registerExtension(namespace); 68 } 69 else if (func instanceof FuncExtFunctionAvailable) 70 { 71 String arg = ((FuncExtFunctionAvailable)func).getArg0().toString(); 72 if (arg.indexOf(":") > 0) 73 { 74 String prefix = arg.substring(0,arg.indexOf(":")); 75 String namespace = this.m_sroot.getNamespaceForPrefix(prefix); 76 m_sroot.getExtensionNamespacesManager().registerExtension(namespace); 77 } 78 } 79 return true; 80 } 81 82 } 83
