/*
* 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: XPathFunction.java 446598 2006-09-15 12:55:40Z jeremias $
package javax.xml.xpath;
import java.util.List;
/**
* <p><code>XPathFunction</code> provides access to XPath functions.</p>
*
* <p>Functions are identified by QName and arity in XPath.</p>
*
* @author <a href="mailto:Norman.Walsh@Sun.com">Norman Walsh</a>
* @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
* @version $Revision: 446598 $, $Date: 2006-09-15 05:55:40 -0700 (Fri, 15 Sep 2006) $
* @since 1.5
*/
public interface XPathFunction {
/**
* <p>Evaluate the function with the specified arguments.</p>
*
* <p>To the greatest extent possible, side-effects should be avoided in the
* definition of extension functions. The implementation evaluating an
* XPath expression is under no obligation to call extension functions in
* any particular order or any particular number of times.</p>
*
* @param args The arguments, <code>null</code> is a valid value.
*
* @return The result of evaluating the <code>XPath</code> function as an <code>Object</code>.
*
* @throws XPathFunctionException If <code>args</code> cannot be evaluated with this <code>XPath</code> function.
*/
public Object evaluate(List args)
throws XPathFunctionException;
}