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.collections;
018    
019    /**
020     * Defines a functor interface implemented by classes that do something.
021     * <p>
022     * A <code>Closure</code> represents a block of code which is executed from
023     * inside some block, function or iteration. It operates an input object.
024     * <p>
025     * Standard implementations of common closures are provided by
026     * {@link ClosureUtils}. These include method invokation and for/while loops.
027     *  
028     * @since Commons Collections 1.0
029     * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
030     *
031     * @author James Strachan
032     * @author Nicola Ken Barozzi
033     * @author Stephen Colebourne
034     */
035    public interface Closure {
036    
037        /**
038         * Performs an action on the specified input object.
039         *
040         * @param input  the input to execute on
041         * @throws ClassCastException (runtime) if the input is the wrong class
042         * @throws IllegalArgumentException (runtime) if the input is invalid
043         * @throws FunctorException (runtime) if any other error occurs
044         */
045        public void execute(Object input);
046    
047    }