UtilityAndArithmetic

Business Purpose

Provides static utility methods for common monetary operations such as comparison, aggregation, and safe arithmetic with null handling. [AI Inference] These complement the instance methods on monetary objects for convenience and safety.

Current Behaviors

• MoneyUtils.isZero(MoneyProvider) checks if amount is zero MoneyUtils.java:53.
• MoneyUtils.isPositive(MoneyProvider) checks positivity MoneyUtils.java:65.
• MoneyUtils.max(Money, Money) returns the larger of two MoneyUtils.java:117.
• MoneyUtils.min(Money, Money) returns the smaller MoneyUtils.java:138.
• MoneyUtils.add(Money, Money) adds two amounts with currency check MoneyUtils.java:160.
• MoneyUtils.subtract(Money, Money) subtracts MoneyUtils.java:182.
• Similar overloads for BigMoney MoneyUtils.java:204.
• Ser handles serialization via writeExternal and readExternal (Ser.java:72,112).

Technical Implementation

• MoneyUtils MoneyUtils.java:31 has no design pattern; it's a set of static methods.
• Null parameters cause NullPointerException via checkNotNull MoneyUtils.java:31.
• Currency mismatches in add and subtract throw CurrencyMismatchException (implied from methods).
• Ser Ser.java:72 implements Externalizable and is marked IMMUTABLE_VALUE_OBJECT.
• Ser methods are @Override (Ser.java:72,112) and handle BigMoney and CurrencyUnit serialization.

Definition of Done

• MoneyUtils.max(Money.of(USD, 10), Money.of(USD, 20)) returns the Money with 20.
• MoneyUtils.add(Money.of(EUR, 5), Money.of(EUR, 3)) returns a Money with EUR and amount 8.
• Passing a null MoneyProvider to isZero throws NullPointerException.
• Attempting add with different currencies throws CurrencyMismatchException.
• Serializing a BigMoney and deserializing results in an equal object.
• MoneyUtils.isNegative(BigMoney.of(GBP, -1)) returns true.