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.math3; 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 * @since 2.0 27 */ 28 public interface Field<T> { 29 30 /** Get the additive identity of the field. 31 * <p> 32 * The additive identity is the element e<sub>0</sub> of the field such that 33 * for all elements a of the field, the equalities a + e<sub>0</sub> = 34 * e<sub>0</sub> + a = a hold. 35 * </p> 36 * @return additive identity of the field 37 */ getZero()38 T getZero(); 39 40 /** Get the multiplicative identity of the field. 41 * <p> 42 * The multiplicative identity is the element e<sub>1</sub> of the field such that 43 * for all elements a of the field, the equalities a × e<sub>1</sub> = 44 * e<sub>1</sub> × a = a hold. 45 * </p> 46 * @return multiplicative identity of the field 47 */ getOne()48 T getOne(); 49 50 /** 51 * Returns the runtime class of the FieldElement. 52 * 53 * @return The {@code Class} object that represents the runtime 54 * class of this object. 55 */ getRuntimeClass()56 Class<? extends FieldElement<T>> getRuntimeClass(); 57 58 } 59