MapsStreams.java

import java.util.List;

public class TaxCalculator {

    // Define a list of tax brackets
    private static final List<TaxBracket> taxBrackets = List.of(
        new TaxBracket(0, 10225, 0.0),
        new TaxBracket(10225, 26070, 0.11),
        new TaxBracket(26070, 74545, 0.30),
        new TaxBracket(74545, 160336, 0.41),
        new TaxBracket(160336, Double.MAX_VALUE, 0.45)
    );

    // Method to calculate the tax based on income
    public double calculateTax(double income) {
        return taxBrackets.stream()
            .map(bracket -> bracket.calculateTax(income))
            .reduce(0.0, Double::sum);
    }

    // Main method to test the tax calculation
    public static void main(String[] args) {
        TaxCalculator calculator = new TaxCalculator();
        System.out.println(calculator.calculateTax(50000));
    }

    // Inner class representing a tax bracket
    private static class TaxBracket {
        double lowerLimit;
        double upperLimit;
        double rate;

        // Constructor for TaxBracket
        TaxBracket(double lowerLimit, double upperLimit, double rate) {
            this.lowerLimit = lowerLimit;
            this.upperLimit = upperLimit;
            this.rate = rate;
        }

        // Method to calculate the tax for a given income based on this bracket
        double calculateTax(double income) {
            if (income > lowerLimit) {
                return (Math.min(income, upperLimit) - lowerLimit) * rate;
            }
            return 0;
        }
    }
}