Addition.java
- /*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.apache.commons.numbers.core;
- /**
- * Addition.
- *
- * @param <T> Type of elements.
- */
- public interface Addition<T> {
- /**
- * Binary addition.
- *
- * @param a Element.
- * @return {@code this + a}.
- */
- T add(T a);
- /**
- * Identity element.
- *
- * @return the field element such that for all {@code a},
- * {@code zero().add(a).equals(a)} is {@code true}.
- */
- T zero();
- /**
- * Additive inverse.
- *
- * @return {@code -this}.
- */
- T negate();
- /**
- * Check if this is a neutral element of addition, i.e. {@code this.add(a)} returns
- * {@code a} or an element representing the same value as {@code a}.
- *
- * <p>The default implementation calls {@link Object#equals(Object) equals(zero())}.
- * Implementations may want to employ more a efficient method. This may even
- * be required if an implementation has multiple representations of {@code zero} and its
- * {@code equals} method differentiates between them.
- *
- * @return {@code true} if {@code this} is a neutral element of addition.
- * @see #zero()
- * @since 1.2
- */
- default boolean isZero() {
- return this.equals(zero());
- }
- }