/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed 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: FuncLoader.java,v 1.1.2.1 2005/08/01 01:30:35 jeffsuttor Exp $
*/
package com.sun.org.apache.xpath.internal.compiler;
import javax.xml.transform.TransformerException;
import com.sun.org.apache.xpath.internal.functions.Function;
/**
* Lazy load of functions into the function table as needed, so we don't
* have to load all the functions allowed in XPath and XSLT on startup.
* @xsl.usage advanced
*/
public class FuncLoader
{
/** The function ID, which may correspond to one of the FUNC_XXX values
* found in {@link com.sun.org.apache.xpath.internal.compiler.FunctionTable}, but may
* be a value installed by an external module. */
private int m_funcID;
/** The class name of the function. Must not be null. */
private String m_funcName;
/**
* Get the local class name of the function class. If function name does
* not have a '.' in it, it is assumed to be relative to
* 'com.sun.org.apache.xpath.internal.functions'.
*
* @return The class name of the {com.sun.org.apache.xpath.internal.functions.Function} class.
*/
public String getName()
{
return m_funcName;
}
/**
* Construct a function loader
*
* @param funcName The class name of the {com.sun.org.apache.xpath.internal.functions.Function}
* class, which, if it does not have a '.' in it, is assumed to
* be relative to 'com.sun.org.apache.xpath.internal.functions'.
* @param funcID The function ID, which may correspond to one of the FUNC_XXX
* values found in {@link com.sun.org.apache.xpath.internal.compiler.FunctionTable}, but may
* be a value installed by an external module.
*/
public FuncLoader(String funcName, int funcID)
{
super();
m_funcID = funcID;
m_funcName = funcName;
}
/**
* Get a Function instance that this instance is liaisoning for.
*
* @return non-null reference to Function derivative.
*
* @throws javax.xml.transform.TransformerException if ClassNotFoundException,
* IllegalAccessException, or InstantiationException is thrown.
*/
Function getFunction() throws TransformerException
{
try
{
String className = m_funcName;
if (className.indexOf(".") < 0) {
className = "com.sun.org.apache.xpath.internal.functions." + className;
}
//hack for loading only built-in function classes.
String subString = className.substring(0,className.lastIndexOf('.'));
if(!(subString.equals ("com.sun.org.apache.xalan.internal.templates") ||
subString.equals ("com.sun.org.apache.xpath.internal.functions"))) {
throw new TransformerException("Application can't install his own xpath function.");
}
return (Function) ObjectFactory.newInstance(
className, ObjectFactory.findClassLoader(), true);
}
catch (ObjectFactory.ConfigurationError e)
{
throw new TransformerException(e.getException());
}
}
}