    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.optim.linear;
    018
    019    /**
    020     * Types of relationships between two cells in a Solver {@link LinearConstraint}.
    021     *
    022     * @version $Id: Relationship.java 1416643 2012-12-03 19:37:14Z tn $
    023     * @since 2.0
    024     */
    025    public enum Relationship {
    026        /** Equality relationship. */
    027        EQ("="),
    028        /** Lesser than or equal relationship. */
    029        LEQ("<="),
    030        /** Greater than or equal relationship. */
    031        GEQ(">=");
    032
    033        /** Display string for the relationship. */
    034        private final String stringValue;
    035
    036        /**
    037         * Simple constructor.
    038         *
    039         * @param stringValue Display string for the relationship.
    040         */
    041        private Relationship(String stringValue) {
    042            this.stringValue = stringValue;
    043        }
    044
    045        @Override
    046        public String toString() {
    047            return stringValue;
    048        }
    049
    050        /**
    051         * Gets the relationship obtained when multiplying all coefficients by -1.
    052         *
    053         * @return the opposite relationship.
    054         */
    055        public Relationship oppositeRelationship() {
    056            switch (this) {
    057            case LEQ :
    058                return GEQ;
    059            case GEQ :
    060                return LEQ;
    061            default :
    062                return EQ;
    063            }
    064        }
    065    }