1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.numbers.core; 18 19 /** 20 * Addition. 21 * 22 * @param <T> Type of elements. 23 */ 24 public interface Addition<T> { 25 /** 26 * Binary addition. 27 * 28 * @param a Element. 29 * @return {@code this + a}. 30 */ 31 T add(T a); 32 33 /** 34 * Identity element. 35 * 36 * @return the field element such that for all {@code a}, 37 * {@code zero().add(a).equals(a)} is {@code true}. 38 */ 39 T zero(); 40 41 /** 42 * Additive inverse. 43 * 44 * @return {@code -this}. 45 */ 46 T negate(); 47 }