Calculator Types

public enum CalculatorType {
    SIMPLE_FIXED,
    SIMPLE_INTEREST,
    STEP_FUNCTION,
    DISCRETE_POINTS,
    DAILY_INCREMENT,
    CONTINUOUS_LINEAR_TIME,
    COMPOSITE,
    PERCENTAGE,
    
    // Price Adapters
    UNIT_TO_TOTAL_ADAPTER,
    UNIT_TO_MARGINAL_ADAPTER,
    TOTAL_TO_UNIT_ADAPTER,
    TOTAL_TO_MARGINAL_ADAPTER,
    MARGINAL_TO_TOTAL_ADAPTER,
    MARGINAL_TO_UNIT_ADAPTER
}

public String getTypeName()

CalculatorType type = CalculatorType.STEP_FUNCTION;
String name = type.getTypeName();
// Returns: "step-function"

public String formatDescription(Object value)

CalculatorType type = CalculatorType.SIMPLE_FIXED;
String desc = type.formatDescription(Money.pln(99));
// Returns: "Fixed amount calculator - returns PLN 99.00 regardless"

public Set<String> requiredCreationFields()

CalculatorType type = CalculatorType.STEP_FUNCTION;
Set<String> fields = type.requiredCreationFields();
// Returns: ["basePrice", "stepSize", "stepIncrement"]

Set<String> requiredCalculationFields()

CalculatorType type = CalculatorType.SIMPLE_INTEREST;
Set<String> fields = type.requiredCalculationFields();
// Returns: ["base", "unit"]

public record CalculatorId(UUID id) {
    public static CalculatorId generate();
    public String toString();
}

// Generate new ID
CalculatorId id = CalculatorId.generate();
System.out.println(id);
// Prints: "550e8400-e29b-41d4-a716-446655440000" (UUID format)

// Use in calculator
Calculator calc = new SimpleFixedCalculator(
    id,                      // explicit ID
    "Monthly Fee",
    Money.pln(99),
    Interpretation.TOTAL
);

CalculatorId retrievedId = calc.getId();
// Returns the same ID

public record CalculatorView(
    CalculatorId id,
    String name,
    CalculatorType type
) {}

// Create view from calculator
Calculator calc = new SimpleFixedCalculator("Fee", Money.pln(99));
CalculatorView view = new CalculatorView(
    calc.getId(),
    calc.name(),
    calc.getType()
);

// Use in API response
return Response.ok(view).build();

public enum StepBoundary {
    EXCLUSIVE,  // [0, N), [N, 2N), [2N, 3N)...
    INCLUSIVE   // [0, N], [N+1, 2N+1], [2N+2, 3N+2]...
}

// Validate parameters before calculation
Calculator calculator = new StepFunctionCalculator(
    "Volume Pricing",
    Money.pln(100),
    BigDecimal.valueOf(10),
    BigDecimal.valueOf(5)
);

CalculatorType type = calculator.getType();
Set<String> required = type.requiredCalculationFields();
// Returns: ["quantity"]

Parameters params = Parameters.of("quantity", BigDecimal.valueOf(15));

if (!params.containsAll(required)) {
    throw new IllegalArgumentException(
        "Missing required parameters: " + required
    );
}

Money price = calculator.calculate(params);
// Calculation proceeds safely