    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
    018    package org.apache.commons.math.optimization.linear;
    019
    020    /**
    021     * Types of relationships between two cells in a Solver {@link LinearConstraint}.
    022     * @version $Revision: 1003886 $ $Date: 2010-10-02 23:04:44 +0200 (sam. 02 oct. 2010) $
    023     * @since 2.0
    024     */
    025    public enum Relationship {
    026
    027        /** Equality relationship. */
    028        EQ("="),
    029
    030        /** Lesser than or equal relationship. */
    031        LEQ("<="),
    032
    033        /** Greater than or equal relationship. */
    034        GEQ(">=");
    035
    036        /** Display string for the relationship. */
    037        private final String stringValue;
    038
    039        /** Simple constructor.
    040         * @param stringValue display string for the relationship
    041         */
    042        private Relationship(String stringValue) {
    043            this.stringValue = stringValue;
    044        }
    045
    046        /** {@inheritDoc} */
    047        @Override
    048        public String toString() {
    049            return stringValue;
    050        }
    051
    052        /**
    053         * Get the relationship obtained when multiplying all coefficients by -1.
    054         * @return relationship obtained when multiplying all coefficients by -1
    055         */
    056        public Relationship oppositeRelationship() {
    057            switch (this) {
    058            case LEQ :
    059                return GEQ;
    060            case GEQ :
    061                return LEQ;
    062            default :
    063                return EQ;
    064            }
    065        }
    066
    067    }