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Object-Oriented Programming/Validation/Java

< Object-Oriented Programming | Validation

main.java

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/** This program demonstrates use of the Temperature class. **/

public class Main{
    public static void main(String[] args){
        var temperature = new Temperature();
        temperature.setCelsius(37);
        System.out.println(temperature.getFahrenheit());

        temperature = new Temperature();
        temperature.setFahrenheit(98.6);
        System.out.println(temperature.getCelsius());

        temperature = new Temperature();
        System.out.println(temperature.toCelsius(98.6));
        System.out.println(temperature.toFahrenheit(37));

        try {
            temperature = new Temperature();
            temperature.setCelsius(-500);
        }
        catch(Exception exception) {
            System.out.println(exception.getMessage());
        }

        try {
            temperature = new Temperature();
            temperature.setFahrenheit(-600);
        }
        catch(Exception exception) {
            System.out.println(exception.getMessage());
        }

        try {
            System.out.println(temperature.toCelsius(-700));
        }
        catch(Exception exception) {
            System.out.println(exception.getMessage());
        }

        try {
            System.out.println(temperature.toFahrenheit(-800));
        }
        catch(Exception exception) {
            System.out.println(exception.getMessage());
        }
    }
}

Temperature.java

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/** Temperature converter. Provides temperature conversion functions. Supports Fahrenheit and Celius temperatures.

Examples:

    Temperature temperature = new Temperature();
    temperature.setCelsius(37);
    System.out.println(temp.getFarenheit());

    temperature = new Temperature();
    temperature.setFahrenheit(98.6);
    System.out.println(temp.getCelcius());

    temperature = new Temperature();
    System.out.println(temp4.toCelsius(98.6));
    System.out.println(temp4.toFahrenheit(37));

**/

public class Temperature {
    private double _celsius;
    private double _fahrenheit;

    // Returns absolute zero Celsius.
    public double getAbsoluteZeroCelsius() {
        return -273.15;
    }

    //Returns absolute zero Fahrenheit.
    public double getAbsoluteZeroFahrenheit() {
        return -459.67;
    }

    // Returns Celsius value.
    public double getCelsius() {
        return this._celsius;
    }

    // Sets Celsius value.
    public void setCelsius(double value) {
        this._celsius = this.validateCelsius(value);
        this._fahrenheit = this.toFahrenheit(value);
    }

    // Returns Fahrenheit value.
    public double getFahrenheit() {
        return this._fahrenheit;
    }

    // Sets Celsius value.
    public void setFahrenheit(double value) {
        this._fahrenheit = this.validateFahrenheit(value);
        this._celsius = this.toCelsius(value);
    }

    // Converts Fahrenheit temperature to Celsius.
    public double toCelsius(double fahrenheit) {
        fahrenheit = validateFahrenheit(fahrenheit);
        return (fahrenheit - 32) * 5.0 / 9.0;
    }

    // Converts Celsius temperature to Fahrenheit.
    public double toFahrenheit(double celsius) {
        celsius = validateCelsius(celsius);
        return celsius * 9.0 / 5.0 + 32;
    }

    // Validates Celsius temperature.
    // Throws error if Celsius temperature is below absolute zero.
    private double validateCelsius(double celsius) {
        if (celsius < this.getAbsoluteZeroCelsius()) {
            throw new IllegalArgumentException(
                "celsius must not be below absolute zero (" +
                this.getAbsoluteZeroCelsius() + "). Received " + celsius);
        }

        return celsius;
    }

    // Validates Fahrenheit temperature.
    // Throws error if Fahrenheit temperature is below absolute zero.
    private double validateFahrenheit(double fahrenheit) {
        if (fahrenheit < this.getAbsoluteZeroFahrenheit()) {
            throw new IllegalArgumentException(
                "fahrenheit must not be below absolute zero (" +
                this.getAbsoluteZeroFahrenheit() + "). Received " + fahrenheit);
        }

        return fahrenheit;
    }
}

Try It

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Copy and paste the code above into one of the following free online development environments or use your own Java compiler / interpreter / IDE.

See Also

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