/*
* 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.
*/
package org.apache.commons.jxpath;
/**
* Extension function interface. Extension functions are grouped into
* {@link Functions Functions} objects, which are installed on
* JXPathContexts using the
* {@link JXPathContext#setFunctions JXPathContext.setFunctions()}
* call.
* <p>
* The Function interface can be implemented directly. However,
* most of the time JXPath's built-in implementations should suffice.
* See {@link ClassFunctions ClassFunctions} and
* {@link PackageFunctions PackageFunctions}.
*
* @author Dmitri Plotnikov
* @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
*/
public interface Function {
/**
* Computes the value of the function. Each implementation of Function
* is responsible for conversion of supplied parameters to the required
* argument types.
*
* @param context can be used to acquire the context in which the
* function is being evaluted.
* @param parameters function arguments
* @return Object result
*/
Object invoke(ExpressionContext context, Object[] parameters);
}
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