com.totsp.tom.util.NumberStatistics.java Source code

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Here is the source code for com.totsp.tom.util.NumberStatistics.java

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/**
 *    Copyright 2013 Robert Cooper
 *
 *    Licensed 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 com.totsp.tom.util;

import com.google.common.collect.Iterables;

import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;

/**
 *
 */
public class NumberStatistics<T extends Number & Comparable<T>> extends Statistics<T> {

    private final MathContext context;

    public NumberStatistics(MathContext context) {
        this.context = context;
    }

    public NumberStatistics() {
        this.context = new MathContext(6, RoundingMode.HALF_UP);
    }

    public BigDecimal mean() {
        int count = 0;
        BigDecimal value = new BigDecimal(0, context);
        for (T t : inner) {
            value = value.add(new BigDecimal(t.toString(), context));
            count++;
        }
        return value.divide(new BigDecimal(count), context);
    }

    public BigDecimal medianAveraged() {
        int index = (inner.size() - 1) / 2;
        if (inner.size() % 2 == 1) {
            T low = Iterables.get(inner, index, null);
            return new BigDecimal(low.toString(), context);
        } else {
            int i = 0;
            T low = null;
            T high = null;
            for (T t : inner) {
                if (index == i) {
                    low = t;
                } else if (index + 1 == i) {
                    high = t;
                    break;
                }
                i++;
            }
            return new BigDecimal(high.toString(), context).add(new BigDecimal(low.toString(), context))
                    .divide(new BigDecimal(2, context), context);
        }

    }

}