convert a temperature value from one scale to another - Java java.lang

Java examples for java.lang:Math Convert

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Description

convert a temperature value from one scale to another

Demo Code

/*/*from  w ww .j  a v  a 2s  .  com*/
 * Copyright (C) 2012, 2013 The MaGDAA Project
 *
 * This file is part of the MaGDAA Library Software
 *
 * MaGDAA Library Software is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This source code is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this source code; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        float value = 2.45678f;
        int fromScale = 2;
        int toScale = 2;
        System.out.println(comvertTemperature(value, fromScale, toScale));
    }

    /**
     * constant to define the celsius temperature scale
     */
    public static final int CELSIUS = 0;
    /**
     * constant to define the fahrenheit scale
     */
    public static final int FAHRENHEIT = 1;
    /**
     * constant to define the kelvin temperature scale
     */
    public static final int KELVIN = 2;

    /**
     * convert a temperature value from one scale to another
     * 
     * @param value the temperature
     * @param fromScale the scale to convert from, as defined by one of the temperature related constants in this class
     * @param toScale the scale to convert to , as defined by one of the temperature related constants in this class
     * @return the converted temperature
     * @throws IllegalArgumentException of the fromScale or toScale parameters are invalid
     */
    public static float comvertTemperature(float value, int fromScale,
            int toScale) {

        /*
         * determine which conversion to undertake
         */
        switch (fromScale) {
        case CELSIUS:
            // convert from celsius
            switch (toScale) {
            case FAHRENHEIT:
                // switch from celsius to fahrenheit
                return convertFromCelsiusToFahrenheit(value);
            case KELVIN:
                // switch from celsius to Kelvin
                return convertFromCelsiusToKelvin(value);
            default:
                throw new IllegalArgumentException("the toScale is invalid");
            }
        case FAHRENHEIT:
            // convert from FAHRENHEIT
            switch (toScale) {
            case CELSIUS:
                // convert from fahrenheit to celsius
                return convertFromFahrenheitToCelsius(value);
            case KELVIN:
                // convert from fahrenheit to kelvin
                return convertFromFahrenheitToKelvin(value);
            default:
                throw new IllegalArgumentException("the toScale is invalid");
            }
        case KELVIN:
            // convert from kelvin
            switch (toScale) {
            case CELSIUS:
                return convertFromKelvinToCelsius(value);
            case FAHRENHEIT:
                return convertFromKelvinToFahrenheit(value);
            default:
                throw new IllegalArgumentException("the toScale is invalid");
            }
        default:
            throw new IllegalArgumentException("the fromScale is invalid");
        }
    }

    private static float convertFromCelsiusToFahrenheit(float value) {
        return value * 9 / 5 + 32;
    }

    private static float convertFromCelsiusToKelvin(float value) {
        return value + 273.15f;
    }

    private static float convertFromFahrenheitToCelsius(float value) {
        return (value - 32) * 5 / 9;
    }

    private static float convertFromFahrenheitToKelvin(float value) {
        return convertFromCelsiusToKelvin(convertFromFahrenheitToCelsius(value));
    }

    private static float convertFromKelvinToCelsius(float value) {
        return value - 273.15f;
    }

    private static float convertFromKelvinToFahrenheit(float value) {
        return convertFromCelsiusToFahrenheit(convertFromKelvinToCelsius(value));
    }
}

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