    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;
    018
    019    import java.io.Serializable;
    020    import org.apache.commons.math3.util.Pair;
    021
    022    /**
    023     * This class holds a point and the value of an objective function at
    024     * that point.
    025     *
    026     * @see PointVectorValuePair
    027     * @see org.apache.commons.math3.analysis.MultivariateFunction
    028     * @version $Id: PointValuePair.java 1416643 2012-12-03 19:37:14Z tn $
    029     * @since 3.0
    030     */
    031    public class PointValuePair extends Pair<double[], Double> implements Serializable {
    032        /** Serializable UID. */
    033        private static final long serialVersionUID = 20120513L;
    034
    035        /**
    036         * Builds a point/objective function value pair.
    037         *
    038         * @param point Point coordinates. This instance will store
    039         * a copy of the array, not the array passed as argument.
    040         * @param value Value of the objective function at the point.
    041         */
    042        public PointValuePair(final double[] point,
    043                              final double value) {
    044            this(point, value, true);
    045        }
    046
    047        /**
    048         * Builds a point/objective function value pair.
    049         *
    050         * @param point Point coordinates.
    051         * @param value Value of the objective function at the point.
    052         * @param copyArray if {@code true}, the input array will be copied,
    053         * otherwise it will be referenced.
    054         */
    055        public PointValuePair(final double[] point,
    056                              final double value,
    057                              final boolean copyArray) {
    058            super(copyArray ? ((point == null) ? null :
    059                               point.clone()) :
    060                  point,
    061                  value);
    062        }
    063
    064        /**
    065         * Gets the point.
    066         *
    067         * @return a copy of the stored point.
    068         */
    069        public double[] getPoint() {
    070            final double[] p = getKey();
    071            return p == null ? null : p.clone();
    072        }
    073
    074        /**
    075         * Gets a reference to the point.
    076         *
    077         * @return a reference to the internal array storing the point.
    078         */
    079        public double[] getPointRef() {
    080            return getKey();
    081        }
    082
    083        /**
    084         * Replace the instance with a data transfer object for serialization.
    085         * @return data transfer object that will be serialized
    086         */
    087        private Object writeReplace() {
    088            return new DataTransferObject(getKey(), getValue());
    089        }
    090
    091        /** Internal class used only for serialization. */
    092        private static class DataTransferObject implements Serializable {
    093            /** Serializable UID. */
    094            private static final long serialVersionUID = 20120513L;
    095            /**
    096             * Point coordinates.
    097             * @Serial
    098             */
    099            private final double[] point;
    100            /**
    101             * Value of the objective function at the point.
    102             * @Serial
    103             */
    104            private final double value;
    105
    106            /** Simple constructor.
    107             * @param point Point coordinates.
    108             * @param value Value of the objective function at the point.
    109             */
    110            public DataTransferObject(final double[] point, final double value) {
    111                this.point = point.clone();
    112                this.value = value;
    113            }
    114
    115            /** Replace the deserialized data transfer object with a {@link PointValuePair}.
    116             * @return replacement {@link PointValuePair}
    117             */
    118            private Object readResolve() {
    119                return new PointValuePair(point, value, false);
    120            }
    121        }
    122    }