javax.xml.xpath.XPathFunctionResolver Maven / Gradle / Ivy
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* 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,
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* See the License for the specific language governing permissions and
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*/
// $Id: XPathFunctionResolver.java 446598 2006-09-15 12:55:40Z jeremias $
package javax.xml.xpath;
import javax.xml.namespace.QName;
/**
* XPathFunctionResolver provides access to the set of user defined XPathFunctions.
*
* XPath functions are resolved by name and arity.
* The resolver is not needed for XPath built-in functions and the resolver
* cannot be used to override those functions.
*
* In particular, the resolver is only called for functions in an another
* namespace (functions with an explicit prefix). This means that you cannot
* use the XPathFunctionResolver to implement specifications
* like XML-Signature Syntax
* and Processing which extend the function library of XPath 1.0 in the
* same namespace. This is a consequence of the design of the resolver.
*
* If you wish to implement additional built-in functions, you will have to
* extend the underlying implementation directly.
*
* @author Norman Walsh
* @author Jeff Suttor
* @version $Revision: 446598 $, $Date: 2006-09-15 08:55:40 -0400 (Fri, 15 Sep 2006) $
* @see XML Path Language (XPath) Version 1.0, Core Function Library
* @since 1.5
*/
public interface XPathFunctionResolver {
/**
* Find a function in the set of available functions.
*
* If functionName or arity is null, then a NullPointerException is thrown.
*
* @param functionName The function name.
* @param arity The number of arguments that the returned function must accept.
*
* @return The function or null if no function named functionName with arity arguments exists.
*
* @throws NullPointerException If functionName or arity is null.
*/
public XPathFunction resolveFunction(QName functionName, int arity);
}