| /* |
| * 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 |
| * limitations under the License. |
| */ |
| /* |
| * $Id: ExtensionHandler.java 468637 2006-10-28 06:51:02Z minchau $ |
| */ |
| package org.apache.xalan.extensions; |
| |
| import java.io.IOException; |
| import java.util.Vector; |
| |
| import javax.xml.transform.TransformerException; |
| |
| import org.apache.xalan.templates.ElemTemplateElement; |
| import org.apache.xalan.templates.Stylesheet; |
| import org.apache.xalan.transformer.TransformerImpl; |
| import org.apache.xpath.functions.FuncExtFunction; |
| |
| /** |
| * Abstract base class for handling an extension namespace for XPath. |
| * Provides functions to test a function's existence and call a function. |
| * Also provides functions for calling an element and testing for |
| * an element's existence. |
| * |
| * @author Sanjiva Weerawarana (sanjiva@watson.ibm.com) |
| * @xsl.usage internal |
| */ |
| public abstract class ExtensionHandler |
| { |
| |
| /** uri of the extension namespace */ |
| protected String m_namespaceUri; |
| |
| /** scripting language of implementation */ |
| protected String m_scriptLang; |
| |
| /** |
| * This method loads a class using the context class loader if we're |
| * running under Java2 or higher. |
| * |
| * @param className Name of the class to load |
| */ |
| static Class getClassForName(String className) |
| throws ClassNotFoundException |
| { |
| // Hack for backwards compatibility with XalanJ1 stylesheets |
| if(className.equals("org.apache.xalan.xslt.extensions.Redirect")) { |
| className = "org.apache.xalan.lib.Redirect"; |
| } |
| |
| return ObjectFactory.findProviderClass( |
| className, ObjectFactory.findClassLoader(), true); |
| } |
| |
| /** |
| * Construct a new extension namespace handler given all the information |
| * needed. |
| * |
| * @param namespaceUri the extension namespace URI that I'm implementing |
| * @param scriptLang language of code implementing the extension |
| */ |
| protected ExtensionHandler(String namespaceUri, String scriptLang) |
| { |
| m_namespaceUri = namespaceUri; |
| m_scriptLang = scriptLang; |
| } |
| |
| /** |
| * Tests whether a certain function name is known within this namespace. |
| * @param function name of the function being tested |
| * @return true if its known, false if not. |
| */ |
| public abstract boolean isFunctionAvailable(String function); |
| |
| /** |
| * Tests whether a certain element name is known within this namespace. |
| * @param element Name of element to check |
| * @return true if its known, false if not. |
| */ |
| public abstract boolean isElementAvailable(String element); |
| |
| /** |
| * Process a call to a function. |
| * |
| * @param funcName Function name. |
| * @param args The arguments of the function call. |
| * @param methodKey A key that uniquely identifies this class and method call. |
| * @param exprContext The context in which this expression is being executed. |
| * |
| * @return the return value of the function evaluation. |
| * |
| * @throws TransformerException if parsing trouble |
| */ |
| public abstract Object callFunction( |
| String funcName, Vector args, Object methodKey, |
| ExpressionContext exprContext) throws TransformerException; |
| |
| /** |
| * Process a call to a function. |
| * |
| * @param extFunction The XPath extension function. |
| * @param args The arguments of the function call. |
| * @param exprContext The context in which this expression is being executed. |
| * |
| * @return the return value of the function evaluation. |
| * |
| * @throws TransformerException if parsing trouble |
| */ |
| public abstract Object callFunction( |
| FuncExtFunction extFunction, Vector args, |
| ExpressionContext exprContext) throws TransformerException; |
| |
| /** |
| * Process a call to this extension namespace via an element. As a side |
| * effect, the results are sent to the TransformerImpl's result tree. |
| * |
| * @param localPart Element name's local part. |
| * @param element The extension element being processed. |
| * @param transformer Handle to TransformerImpl. |
| * @param stylesheetTree The compiled stylesheet tree. |
| * @param methodKey A key that uniquely identifies this class and method call. |
| * |
| * @throws XSLProcessorException thrown if something goes wrong |
| * while running the extension handler. |
| * @throws MalformedURLException if loading trouble |
| * @throws FileNotFoundException if loading trouble |
| * @throws IOException if loading trouble |
| * @throws TransformerException if parsing trouble |
| */ |
| public abstract void processElement( |
| String localPart, ElemTemplateElement element, TransformerImpl transformer, |
| Stylesheet stylesheetTree, Object methodKey) throws TransformerException, IOException; |
| } |