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.math; 18 19 /** 20 * Interface representing a <a href="http://mathworld.wolfram.com/Field.html">field</a>. 21 * <p> 22 * Classes implementing this interface will often be singletons. 23 * </p> 24 * @param <T> the type of the field elements 25 * @see FieldElement 26 * @version $Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $ 27 * @since 2.0 28 */ 29 public interface Field<T> { 30 31 /** Get the additive identity of the field. 32 * <p> 33 * The additive identity is the element e<sub>0</sub> of the field such that 34 * for all elements a of the field, the equalities a + e<sub>0</sub> = 35 * e<sub>0</sub> + a = a hold. 36 * </p> 37 * @return additive identity of the field 38 */ getZero()39 T getZero(); 40 41 /** Get the multiplicative identity of the field. 42 * <p> 43 * The multiplicative identity is the element e<sub>1</sub> of the field such that 44 * for all elements a of the field, the equalities a × e<sub>1</sub> = 45 * e<sub>1</sub> × a = a hold. 46 * </p> 47 * @return multiplicative identity of the field 48 */ getOne()49 T getOne(); 50 51 } 52