001/*
002 *  Copyright 2013 Chris Pheby
003 *
004 *  Licensed under the Apache License, Version 2.0 (the "License");
005 *  you may not use this file except in compliance with the License.
006 *  You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 *  Unless required by applicable law or agreed to in writing, software
011 *  distributed under the License is distributed on an "AS IS" BASIS,
012 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 *  See the License for the specific language governing permissions and
014 *  limitations under the License.
015 */
016package org.jadira.quant.api;
017
018/**
019 * This interface defines a composite function. It is not a higher order function as its output is a
020 * Number. It is intended to be adaptable to /compatible with {@code java.util.function.Function}
021 * being introduced into Java 8.
022 * 
023 * @param <T> The input type of the function.
024 * @param <R> The result type of the function.
025 */
026//@FunctionalInterface for Java 8
027public interface CompositeFunction<R extends Number, T extends QuantitativeFunction<R, ?>> extends QuantitativeFunction<R, T> {
028
029        /**
030         * Apply a function to the input argument T, yielding an appropriate result R.
031         * 
032         * @param value the input value
033         * @return the result of the function
034         */
035        R apply(T value);
036}