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    }