Java DoubleUnaryOperator

Introduction

In Java, the DoubleUnaryOperator interface is a functional interface that represents an operation on a single double-valued operand, producing a double result. It is part of the java.util.function package and is commonly used for operations that transform double values.

Table of Contents

1. What is DoubleUnaryOperator?
2. Methods and Syntax
3. Examples of DoubleUnaryOperator
4. Real-World Use Case
5. Conclusion

1. What is DoubleUnaryOperator?

DoubleUnaryOperator is a functional interface that takes a single double as input and returns a double as a result. It is useful for operations like mathematical transformations or calculations on double values.

2. Methods and Syntax

The main method in the DoubleUnaryOperator interface is:

• double applyAsDouble(double operand): Applies this operator to the given operand and returns a double result.

Syntax

DoubleUnaryOperator operator = (double operand) -> {
    // operation on operand
    return result;
};

3. Examples of DoubleUnaryOperator

Example 1: Doubling a Value

import java.util.function.DoubleUnaryOperator;

public class DoublingExample {
    public static void main(String[] args) {
        // Define a DoubleUnaryOperator that doubles the value
        DoubleUnaryOperator doubleValue = (operand) -> operand * 2;

        double result = doubleValue.applyAsDouble(5.5);

        System.out.println("Doubled Value: " + result);
    }
}

Output:

Doubled Value: 11.0

Example 2: Calculating the Square

import java.util.function.DoubleUnaryOperator;

public class SquareExample {
    public static void main(String[] args) {
        // Define a DoubleUnaryOperator that calculates the square of the value
        DoubleUnaryOperator square = (operand) -> operand * operand;

        double result = square.applyAsDouble(4.0);

        System.out.println("Square: " + result);
    }
}

Output:

Square: 16.0

4. Real-World Use Case: Applying a Tax Rate

In financial applications, DoubleUnaryOperator can be used to apply a tax rate to a given amount.

import java.util.function.DoubleUnaryOperator;

public class TaxCalculator {
    public static void main(String[] args) {
        // Define a DoubleUnaryOperator to apply a 10% tax
        DoubleUnaryOperator applyTax = (amount) -> amount * 1.10;

        double totalAmount = applyTax.applyAsDouble(100.0);

        System.out.println("Total Amount with Tax: " + totalAmount);
    }
}

Output:

Total Amount with Tax: 110.0

Conclusion

The DoubleUnaryOperator interface is a practical tool in Java for transforming double values. It is particularly useful for mathematical calculations and financial computations. Using DoubleUnaryOperator can enhance code readability and maintainability, especially in functional programming contexts.