    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.stat.descriptive.rank;
    018
    019    import java.io.Serializable;
    020
    021    import org.apache.commons.math3.exception.NullArgumentException;
    022
    023
    024    /**
    025     * Returns the median of the available values.  This is the same as the 50th percentile.
    026     * See {@link Percentile} for a description of the algorithm used.
    027     * <p>
    028     * <strong>Note that this implementation is not synchronized.</strong> If
    029     * multiple threads access an instance of this class concurrently, and at least
    030     * one of the threads invokes the <code>increment()</code> or
    031     * <code>clear()</code> method, it must be synchronized externally.</p>
    032     *
    033     * @version $Id: Median.java 1416643 2012-12-03 19:37:14Z tn $
    034     */
    035    public class Median extends Percentile implements Serializable {
    036
    037        /** Serializable version identifier */
    038        private static final long serialVersionUID = -3961477041290915687L;
    039
    040        /**
    041         * Default constructor.
    042         */
    043        public Median() {
    044            // No try-catch or advertised exception - arg is valid
    045            super(50.0);
    046        }
    047
    048        /**
    049         * Copy constructor, creates a new {@code Median} identical
    050         * to the {@code original}
    051         *
    052         * @param original the {@code Median} instance to copy
    053         * @throws NullArgumentException if original is null
    054         */
    055        public Median(Median original) throws NullArgumentException {
    056            super(original);
    057        }
    058
    059    }