Comment by stickfigure | Hacker News Reader

Comment by stickfigure | Hacker News Reader

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I'm surprised nobody has mentioned Joda Money yet:

https://www.joda.org/joda-money/

From the same person that brought us Joda Time (ie, what the java time API was based on). I've used Joda Money a lot and it's great.

Honestly I prefer APIs that look like APIs and I think this trend towards inventing DSLs is a bad one. Rails works because there's a critical mass of people who have adopted what is essentially a whole new language on top of Ruby. A money library doesn't warrant a new language, it's unnecessary cognitive load. This new money library would look fine with simple constructors and method calls.

Joda is impressive and has great performance.

The examples were written using the infix notation but you can just use regular method calls. For example:

val price = Money.of(100, "USD")

val shipping = Money.of(5, "USD")

val subtotal = price.plus(shipping)

val discount = Percentage.of(10)

val total = subtotal.decreaseBy(discount)

total.allocate(2)

total.allocate(60.percent(), 40.percent())

I personally went with Joda money versus the Java money API mentioned above. Our needs are a bit simpler and the Joda Money API is a bit simpler to understand. Our app only deals in USD so I wrote a small utility class to help initialize Money instances so devs don't have to write:

    Money.of(CurrencyUnit.USD, amount)

...everywhere and do a few other things like total Money instances.

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