/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.math3.stat.descriptive.rank;

import java.io.Serializable;

import org.apache.commons.math3.exception.MathIllegalArgumentException;
import org.apache.commons.math3.exception.NullArgumentException;
import org.apache.commons.math3.stat.ranking.NaNStrategy;
import org.apache.commons.math3.util.KthSelector;


Returns the median of the available values. This is the same as the 50th percentile. See Percentile for a description of the algorithm used. 

Note that this implementation is not synchronized. If
multiple threads access an instance of this class concurrently, and at least
one of the threads invokes the increment() or
clear() method, it must be synchronized externally.
/**
 * Returns the median of the available values.  This is the same as the 50th percentile.
 * See {@link Percentile} for a description of the algorithm used.
 * <p>
 * <strong>Note that this implementation is not synchronized.</strong> If
 * multiple threads access an instance of this class concurrently, and at least
 * one of the threads invokes the <code>increment()</code> or
 * <code>clear()</code> method, it must be synchronized externally.</p>
 *
 */
public class Median extends Percentile implements Serializable {

    
Serializable version identifier /** Serializable version identifier */
    private static final long serialVersionUID = -3961477041290915687L;

    
Fixed quantile. /** Fixed quantile. */
    private static final double FIXED_QUANTILE_50 = 50.0;

    
Default constructor.
/**
     * Default constructor.
     */
    public Median() {
        // No try-catch or advertised exception - arg is valid
        super(FIXED_QUANTILE_50);
    }

    
Copy constructor, creates a new Median identical to the original 
Params:
original – the Median instance to copy
Throws:
NullArgumentException – if original is null/**
     * Copy constructor, creates a new {@code Median} identical
     * to the {@code original}
     *
     * @param original the {@code Median} instance to copy
     * @throws NullArgumentException if original is null
     */
    public Median(Median original) throws NullArgumentException {
        super(original);
    }

    
Constructs a Median with the specific EstimationType, NaNStrategy and PivotingStrategy. 
Params:
estimationType – one of the percentile  estimation types
nanStrategy – one of NaNStrategy to handle with NaNs
kthSelector – KthSelector to use for pivoting during search
Throws:
MathIllegalArgumentException – if p is not within (0,100]
NullArgumentException – if type or NaNStrategy passed is null/**
     * Constructs a Median with the specific {@link EstimationType}, {@link NaNStrategy} and {@link PivotingStrategy}.
     *
     * @param estimationType one of the percentile {@link EstimationType  estimation types}
     * @param nanStrategy one of {@link NaNStrategy} to handle with NaNs
     * @param kthSelector {@link KthSelector} to use for pivoting during search
     * @throws MathIllegalArgumentException if p is not within (0,100]
     * @throws NullArgumentException if type or NaNStrategy passed is null
     */
    private Median(final EstimationType estimationType, final NaNStrategy nanStrategy,
                   final KthSelector kthSelector)
        throws MathIllegalArgumentException {
        super(FIXED_QUANTILE_50, estimationType, nanStrategy, kthSelector);
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public Median withEstimationType(final EstimationType newEstimationType) {
        return new Median(newEstimationType, getNaNStrategy(), getKthSelector());
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public Median withNaNStrategy(final NaNStrategy newNaNStrategy) {
        return new Median(getEstimationType(), newNaNStrategy, getKthSelector());
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public Median withKthSelector(final KthSelector newKthSelector) {
        return new Median(getEstimationType(), getNaNStrategy(), newKthSelector);
    }

}