    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     */
    017    package org.apache.commons.math3;
    018
    019    import org.apache.commons.math3.exception.MathArithmeticException;
    020    import org.apache.commons.math3.exception.NullArgumentException;
    021
    022
    023    /**
    024     * Interface representing <a href="http://mathworld.wolfram.com/Field.html">field</a> elements.
    025     * @param <T> the type of the field elements
    026     * @see Field
    027     * @version $Id: FieldElement.java 1416643 2012-12-03 19:37:14Z tn $
    028     * @since 2.0
    029     */
    030    public interface FieldElement<T> {
    031
    032        /** Compute this + a.
    033         * @param a element to add
    034         * @return a new element representing this + a
    035         * @throws NullArgumentException if {@code addend} is {@code null}.
    036         */
    037        T add(T a) throws NullArgumentException;
    038
    039        /** Compute this - a.
    040         * @param a element to subtract
    041         * @return a new element representing this - a
    042         * @throws NullArgumentException if {@code a} is {@code null}.
    043         */
    044        T subtract(T a) throws NullArgumentException;
    045
    046        /**
    047         * Returns the additive inverse of {@code this} element.
    048         * @return the opposite of {@code this}.
    049         */
    050        T negate();
    051
    052        /** Compute n &times; this. Multiplication by an integer number is defined
    053         * as the following sum
    054         * <center>
    055         * n &times; this = &sum;<sub>i=1</sub><sup>n</sup> this.
    056         * </center>
    057         * @param n Number of times {@code this} must be added to itself.
    058         * @return A new element representing n &times; this.
    059         */
    060        T multiply(int n);
    061
    062        /** Compute this &times; a.
    063         * @param a element to multiply
    064         * @return a new element representing this &times; a
    065         * @throws NullArgumentException if {@code a} is {@code null}.
    066         */
    067        T multiply(T a) throws NullArgumentException;
    068
    069        /** Compute this &divide; a.
    070         * @param a element to add
    071         * @return a new element representing this &divide; a
    072         * @throws NullArgumentException if {@code a} is {@code null}.
    073         * @throws MathArithmeticException if {@code a} is zero
    074         */
    075        T divide(T a) throws NullArgumentException, MathArithmeticException;
    076
    077        /**
    078         * Returns the multiplicative inverse of {@code this} element.
    079         * @return the inverse of {@code this}.
    080         * @throws MathArithmeticException if {@code this} is zero
    081         */
    082        T reciprocal() throws MathArithmeticException;
    083
    084        /** Get the {@link Field} to which the instance belongs.
    085         * @return {@link Field} to which the instance belongs
    086         */
    087        Field<T> getField();
    088    }