001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.jxpath;
018    
019    import java.util.Set;
020    
021    /**
022     * A group of Function objects sharing a common namespace or a set of
023     * common namespaces. Use the classes
024     * {@link ClassFunctions ClassFunctions} and
025     * {@link PackageFunctions PackageFunctions}
026     * to register extension functions implemented as Java methods.
027     *
028     * @author Dmitri Plotnikov
029     * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
030     */
031    public interface Functions {
032    
033        /**
034         * Returns all namespaces in which this function collection defines
035         * functions.
036         * @return Set
037         */
038        Set getUsedNamespaces();
039    
040        /**
041         * Returns a Function, if any, for the specified namespace,
042         * name and parameter types.
043         * @param namespace ns
044         * @param name function name
045         * @param parameters Object[]
046         * @return Function
047         */
048        Function getFunction(String namespace, String name, Object[] parameters);
049    }