001    package sysModel;
002    
003    import model.ILambda;
004    
005    /**
006     * No operation.
007     *
008     * @author Mathias Ricken
009     */
010    public class NoOpLambda implements ILambda {
011        /**
012         * Singleton instance.
013         */
014        private static NoOpLambda _instance = null;
015    
016        /**
017         * Return singleton instance.
018         *
019         * @return singleton instance
020         */
021        public static NoOpLambda instance() {
022            if (null == _instance) {
023                _instance = new NoOpLambda();
024            }
025            return _instance;
026        }
027    
028        /**
029         * Private singleton constructor.
030         */
031        private NoOpLambda() {
032        }
033    
034        /**
035         * Do nothing.
036         *
037         * @param param ignored
038         * @return null
039         */
040        public Object apply(Object param) {
041            return null;
042        }
043    }