/*
* 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.
*/
package org.apache.xalan.extensions;
import java.util.List;
import java.util.Vector;
import javax.xml.transform.TransformerException;
import javax.xml.xpath.XPathFunction;
import javax.xml.xpath.XPathFunctionException;
/**
* A sample implementation of XPathFunction, with support for
* EXSLT extension functions and Java extension functions.
*/
public class XPathFunctionImpl implements XPathFunction
{
private ExtensionHandler m_handler;
private String m_funcName;
/**
* Construct an instance of XPathFunctionImpl from the
* ExtensionHandler and function name.
*/
public XPathFunctionImpl(ExtensionHandler handler, String funcName)
{
m_handler = handler;
m_funcName = funcName;
}
/**
* @see javax.xml.xpath.XPathFunction#evaluate(java.util.List)
*/
public Object evaluate(List args)
throws XPathFunctionException
{
Vector argsVec = listToVector(args);
try {
// The method key and ExpressionContext are set to null.
return m_handler.callFunction(m_funcName, argsVec, null, null);
}
catch (TransformerException e)
{
throw new XPathFunctionException(e);
}
}
/**
* Convert a java.util.List to a java.util.Vector.
* No conversion is done if the List is already a Vector.
*/
private static Vector listToVector(List args)
{
if (args == null)
return null;
else if (args instanceof Vector)
return (Vector)args;
else
{
Vector result = new Vector();
result.addAll(args);
return result;
}
}
}