/*
* 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: ExtensionsTable.java 469672 2006-10-31 21:56:19Z minchau $
*/
package org.apache.xalan.extensions;
import java.util.Hashtable;
import java.util.Vector;
import org.apache.xalan.res.XSLMessages;
import org.apache.xalan.res.XSLTErrorResources;
import org.apache.xalan.templates.StylesheetRoot;
import org.apache.xpath.XPathProcessorException;
import org.apache.xpath.functions.FuncExtFunction;
/**
* Class holding a table registered extension namespace handlers
* @xsl.usage internal
*/
public class ExtensionsTable
{
/**
* Table of extensions that may be called from the expression language
* via the call(name, ...) function. Objects are keyed on the call
* name.
* @xsl.usage internal
*/
public Hashtable m_extensionFunctionNamespaces = new Hashtable();
/**
* The StylesheetRoot associated with this extensions table.
*/
private StylesheetRoot m_sroot;
/**
* The constructor (called from TransformerImpl) registers the
* StylesheetRoot for the transformation and instantiates an
* ExtensionHandler for each extension namespace.
* @xsl.usage advanced
*/
public ExtensionsTable(StylesheetRoot sroot)
throws javax.xml.transform.TransformerException
{
m_sroot = sroot;
Vector extensions = m_sroot.getExtensions();
for (int i = 0; i < extensions.size(); i++)
{
ExtensionNamespaceSupport extNamespaceSpt =
(ExtensionNamespaceSupport)extensions.get(i);
ExtensionHandler extHandler = extNamespaceSpt.launch();
if (extHandler != null)
addExtensionNamespace(extNamespaceSpt.getNamespace(), extHandler);
}
}
/**
* Get an ExtensionHandler object that represents the
* given namespace.
* @param extns A valid extension namespace.
*
* @return ExtensionHandler object that represents the
* given namespace.
*/
public ExtensionHandler get(String extns)
{
return (ExtensionHandler) m_extensionFunctionNamespaces.get(extns);
}
/**
* Register an extension namespace handler. This handler provides
* functions for testing whether a function is known within the
* namespace and also for invoking the functions.
*
* @param uri the URI for the extension.
* @param extNS the extension handler.
* @xsl.usage advanced
*/
public void addExtensionNamespace(String uri, ExtensionHandler extNS)
{
m_extensionFunctionNamespaces.put(uri, extNS);
}
/**
* Execute the function-available() function.
* @param ns the URI of namespace in which the function is needed
* @param funcName the function name being tested
*
* @return whether the given function is available or not.
*
* @throws javax.xml.transform.TransformerException
*/
public boolean functionAvailable(String ns, String funcName)
throws javax.xml.transform.TransformerException
{
boolean isAvailable = false;
if (null != ns)
{
ExtensionHandler extNS =
(ExtensionHandler) m_extensionFunctionNamespaces.get(ns);
if (extNS != null)
isAvailable = extNS.isFunctionAvailable(funcName);
}
return isAvailable;
}
/**
* Execute the element-available() function.
* @param ns the URI of namespace in which the function is needed
* @param elemName name of element being tested
*
* @return whether the given element is available or not.
*
* @throws javax.xml.transform.TransformerException
*/
public boolean elementAvailable(String ns, String elemName)
throws javax.xml.transform.TransformerException
{
boolean isAvailable = false;
if (null != ns)
{
ExtensionHandler extNS =
(ExtensionHandler) m_extensionFunctionNamespaces.get(ns);
if (extNS != null) // defensive
isAvailable = extNS.isElementAvailable(elemName);
}
return isAvailable;
}
/**
* Handle an extension function.
* @param ns the URI of namespace in which the function is needed
* @param funcName the function name being called
* @param argVec arguments to the function in a vector
* @param methodKey a unique key identifying this function instance in the
* stylesheet
* @param exprContext a context which may be passed to an extension function
* and provides callback functions to access various
* areas in the environment
*
* @return result of executing the function
*
* @throws javax.xml.transform.TransformerException
*/
public Object extFunction(String ns, String funcName,
Vector argVec, Object methodKey,
ExpressionContext exprContext)
throws javax.xml.transform.TransformerException
{
Object result = null;
if (null != ns)
{
ExtensionHandler extNS =
(ExtensionHandler) m_extensionFunctionNamespaces.get(ns);
if (null != extNS)
{
try
{
result = extNS.callFunction(funcName, argVec, methodKey,
exprContext);
}
catch (javax.xml.transform.TransformerException e)
{
throw e;
}
catch (Exception e)
{
throw new javax.xml.transform.TransformerException(e);
}
}
else
{
throw new XPathProcessorException(XSLMessages.createMessage(XSLTErrorResources.ER_EXTENSION_FUNC_UNKNOWN, new Object[]{ns, funcName }));
//"Extension function '" + ns + ":" + funcName + "' is unknown");
}
}
return result;
}
/**
* Handle an extension function.
* @param extFunction the extension function
* @param argVec arguments to the function in a vector
* @param exprContext a context which may be passed to an extension function
* and provides callback functions to access various
* areas in the environment
*
* @return result of executing the function
*
* @throws javax.xml.transform.TransformerException
*/
public Object extFunction(FuncExtFunction extFunction, Vector argVec,
ExpressionContext exprContext)
throws javax.xml.transform.TransformerException
{
Object result = null;
String ns = extFunction.getNamespace();
if (null != ns)
{
ExtensionHandler extNS =
(ExtensionHandler) m_extensionFunctionNamespaces.get(ns);
if (null != extNS)
{
try
{
result = extNS.callFunction(extFunction, argVec, exprContext);
}
catch (javax.xml.transform.TransformerException e)
{
throw e;
}
catch (Exception e)
{
throw new javax.xml.transform.TransformerException(e);
}
}
else
{
throw new XPathProcessorException(XSLMessages.createMessage(XSLTErrorResources.ER_EXTENSION_FUNC_UNKNOWN,
new Object[]{ns, extFunction.getFunctionName()}));
}
}
return result;
}
}