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 */
017package org.apache.commons.numbers.core;
018
019/**
020 * Addition.
021 *
022 * @param <T> Type of elements.
023 */
024public interface Addition<T> {
025    /**
026     * Binary addition.
027     *
028     * @param a Element.
029     * @return {@code this + a}.
030     */
031    T add(T a);
032
033    /**
034     * Identity element.
035     *
036     * @return the field element such that for all {@code a},
037     * {@code zero().add(a).equals(a)} is {@code true}.
038     */
039    T zero();
040
041    /**
042     * Additive inverse.
043     *
044     * @return {@code -this}.
045     */
046    T negate();
047}