LongMath Class | Guava | Java

LongMath is used to perform mathematical operations on Long values. Basic standalone math functions are divided into the classes IntMath, LongMath, DoubleMath, and BigIntegerMath based on the primary numeric type involved. These classes have parallel structure, but each supports only the relevant subset of functions.

Declaration : The declaration for com.google.common.math.LongMath class is :

@GwtCompatible(emulated = true)
public final class LongMath
   extends Object

Below table shows some of the methods provided by LongMath Class of Guava :

Exceptions :

• log2 : IllegalArgumentException if x <= 0
• log10 : IllegalArgumentException if x <= 0
• pow : IllegalArgumentException if k < 0
• sqrt : IllegalArgumentException if x < 0
• divide : ArithmeticException if q == 0, or if mode == UNNECESSARY and a is not an integer multiple of b
• mod : ArithmeticException if m <= 0
• gcd : IllegalArgumentException if a < 0 or b < 0
• checkedAdd : ArithmeticException if a + b overflows in signed long arithmetic
• checkedSubtract : ArithmeticException if a – b overflows in signed long arithmetic
• checkedMultiply : ArithmeticException if a * b overflows in signed long arithmetic
• checkedPow : ArithmeticException if b to the kth power overflows in signed long arithmetic
• factorial : IllegalArgumentException if n < 0
• binomial : IllegalArgumentException if n < 0, k < 0 or k > n

Some other methods provided by LongMath Class of Guava are :

Example 1 :

// Java code to show implementation of
// LongMath Class of Guava
import java.math.RoundingMode;
import com.google.common.math.LongMath;

class GFG {

    // Driver code
    public static void main(String args[])
    {

        // Creating an object of GFG class
        GFG obj = new GFG();

        // Function calling
        obj.examples();
    }

    private void examples()
    {

        try {

            // exception will be thrown as 80 is not
            // completely divisible by 3
            // thus rounding is required, and
            // RoundingMode is set as UNNESSARY
            System.out.println(LongMath.divide(80, 3, RoundingMode.UNNECESSARY));
        }
        catch (ArithmeticException ex) {
            System.out.println("Error Message is : " + ex.getMessage());
        }
    }
}

Output :

Error Message is : mode was UNNECESSARY, but rounding was necessary

Example 2 :

// Java code to show implementation of
// LongMath Class of Guava
import java.math.RoundingMode;
import com.google.common.math.LongMath;

class GFG {

    // Driver code
    public static void main(String args[])
    {

        // Creating an object of GFG class
        GFG obj = new GFG();

        // Function calling
        obj.examples();
    }

    private void examples()
    {

        // As 120 is divisible by 4, so
        // no exception is thrown
        System.out.println(LongMath.divide(120, 4, RoundingMode.UNNECESSARY));

        // To compute GCD of two integers
        System.out.println("GCD is : " + LongMath.gcd(70, 14));

        // To compute log to base 10
        System.out.println("Log10 is : " + LongMath.log10(1000, RoundingMode.HALF_EVEN));

        // To compute remainder
        System.out.println("modulus is : " + LongMath.mod(125, 5));

        // To compute factorial
        System.out.println("factorial is : " + LongMath.factorial(7));

        // To compute log to base 2
        System.out.println("Log2 is : " + LongMath.log2(8, RoundingMode.HALF_EVEN));

        // To compute square root
        System.out.println("sqrt is : " + LongMath.sqrt(LongMath.pow(12, 2), RoundingMode.HALF_EVEN));
    }
}

Output :

30
GCD is : 14
Log10 is : 3
modulus is : 0
factorial is : 5040
Log2 is : 3
sqrt is : 12

Reference : Google Guava