/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.xalan.extensions;
import java.util.Vector;
import java.lang.reflect.Method;
import java.io.IOException;
import javax.xml.transform.TransformerException;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.apache.xalan.templates.Stylesheet;
import org.apache.xalan.templates.ElemTemplateElement;
import org.apache.xml.utils.QName;
// Temp??
import org.apache.xalan.transformer.TransformerImpl;
/**
* <meta name="usage" content="internal"/>
* 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)
*/
public abstract class ExtensionHandler
{
/** uri of the extension namespace */
protected String m_namespaceUri;
/** scripting language of implementation */
protected String m_scriptLang;
/** a zero length Object array used in getClassForName() */
private static final Object NO_OBJS[] = new Object[0];
/** the Method object for getContextClassLoader */
private static Method getCCL;
static
{
try
{
getCCL = Thread.class.getMethod("getContextClassLoader", new Class[0]);
}
catch (Exception e)
{
getCCL = null;
}
}
/**
* Replacement for Class.forName. This method loads a class using the context class loader
* if we're running under Java2 or higher. If we're running under Java1, this
* method just uses Class.forName to load the class.
*
* @param className Name of the class to load
*/
public static Class getClassForName(String className)
throws ClassNotFoundException
{
Class result = null;
// Hack for backwards compatibility with XalanJ1 stylesheets
if(className.equals("org.apache.xalan.xslt.extensions.Redirect"))
className = "org.apache.xalan.lib.Redirect";
if (getCCL != null)
{
try {
ClassLoader contextClassLoader =
(ClassLoader) getCCL.invoke(Thread.currentThread(), NO_OBJS);
result = contextClassLoader.loadClass(className);
}
catch (ClassNotFoundException cnfe)
{
result = Class.forName(className);
}
catch (Exception e)
{
getCCL = null;
result = Class.forName(className);
}
}
else
result = Class.forName(className);
return result;
}
/**
* 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 function name of the function being tested
*
* @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 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 mode The current mode.
* @param sourceTree The root of the source tree (but don't assume
* it's a Document).
* @param sourceNode The current context node.
* @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;
}