JAZOON'13 - Anatole Tresch - Go for the money (JSR 354) !

Go for the Money - JSR 354

Introduction & Overview

Jazoon 2013

23th October 2013

Anatole Tresch

Bio

Anatole Tresch

Consultant, Coach

Credit Suisse

Core Framework Engineer & Architect

Specification Lead JSR 354

Regular Conference Speaker

Involved also in EE/Config

Twitter/Google+: @atsticks

[email protected]

[email protected]

Java Config JSR https://groups.google.com/forum/#!forum/java-config

Zurich Java Community https://plus.google.com/u/0/communities/106363890913137321158

Looking for enthusiasts for DevoXX4Kids Zurich, Zurich Codegarten

Go for the money - JSR 354 - http://java.net/projects/javamoney 23th October 2013 2

mailto:[email protected]




https://groups.google.com/forum/





https://plus.google.com/u/0/communities/106363890913137321158




Agenda

3

History and Motivation

Overview

Currencies and Monetary Amounts

Extension Points

Formatting & Parsing

JavaMoney OSS Project

Go for the money - JSR 354 - http://java.net/projects/javamoney 23th October 2013

History and Motivation

4 Go for the money - JSR 354 - http://java.net/projects/javamoney 23th October 2013

Earlier Approaches

5

Martin Fowler: A large proportion of the computers in this world manipulate money, so it’s

always puzzled me that money isn’t

actually a first class data type in any

mainstream programming language.

The lack of a type causes problems, the most obvious surrounding currencies…

see http://martinfowler.com/eaaCatalog/m

oney.html

Eric Evans – Time and Money: On project after project, software developers have to reinvent the wheel, creating objects for

simple recurring concepts such as “money”

and “currency”. Although most languages have

a “date” or “time” object, these are

rudimentary, and do not cover many needs, such as recurring sequences of time, durations of time, or intervals of time. …

To be quite frank, their code isn’t more than an academic POC, factories called dollars() or

euros() are useless in real globally deployed frameworks, but he made a good point.


http://martinfowler.com/eaaCatalog/money.html

http://martinfowler.com/eaaCatalog/money.html

Motivation

Monetary values are a key feature

Existing java.util.Currency class is strictly representing

ISO-4217 standard currencies.

No standard value type for monetary amounts

No support for monetary arithmetic or currency conversion

No support for historic currencies

JDK Formatting features lack of flexibility


Scope & Schedule

Standalone scope

Minimum Java Version: 7

Targeting Platform

Java SE 9: Early 2016

Java ME/Embedded 8 oder 9

Started in 2012 by Victor Grazi

Renewal Ballot in February 2013

Early Draft Review May 2013

Public Review starting now!

Final until end of 2013, early 2014


Overview


General Considerations

Minimal, extendible API

Design for the JDK! Use ValueTypes, Interfaces for Interoperation

Naming and Basic Design similar to ThreeTen

Suitable for SE, ME and EE!

Compatibitliy with JodaMoney would be a benefit for the community


Overview of JSR 354 and Javamoney

API: javax.money

CurrencyUnit, MonetaryAmount, MonetaryAdjuster,

MonetaryQuery, MonetaryException

RI: org.javamoney.moneta MoneyCurrency, Money, FastMoney, MonetaryRoundings,

MonetaryFunctions

TCK: org.javamoney.tck

Javamoney extensions (GitHub OSS project): org.javamoney.conversion

org.javamoney.format

org.javamoney.ext

org.javamoney.regions

org.javamoney.validity

org.javamoney.calc


Currencies and Monetary Amounts

javax.money


Currencies

Some Details about ISO 4217

12

Special Codes

Ambiguities

Unmodeled Aspects

Minor/Major

units

Precious Metals (XAU, XAG) Testing (XTS) No Currency (XXX) Supranational currencies, e.g. East Caribbean dollar, the CFP franc, the CFA franc.

CFA franc: West African CFA franc und Central African

CFA franc = denotes 2 effectively interchangeable (!). Switzerland: CHF, CHE (WIR-EURO), CHW (WIR) USA: USD, USN (next day), USS (same day)

Legal acceptance, e.g. Indian Rupees are legally accepted in Buthan/Nepal, but not vice versa.

Typically 1/100, rarely 1/1000, but also 1/5 (Mauritania, Madagaskar), 0.00000001 (BitCoin), multiple minors, supermajors


Currencies (continued)

”Virtual” Currencies

13 13th June 2013

Video Game Currencies Gold, Gil, Rupees, Credits, Gold Rings, Hearts, Zenny, Potch, Munny, Nuyen…

Facebook Credits Virtual currency you can use to buy virtual goods in any games or apps of the Facebook platform that accept payments. You can purchase Facebook Credits directly from within an app using your credit card, PayPal, mobile phone and many other local payment methods.

Bitcoin (sign: BTC) Bittcoin is a decentralized digital currency based on an open-source, peer-to-peer internet protocol. It was introduced by a pseudonymous developer named Satoshi Nakamoto in 2009.

Go for the money - JSR 354 - http://java.net/projects/javamoney


API and Implementation

14

Allow currencies with arbitrary other (non ISO 4217) currency codes

Additional implementation Aspects Register additional Currencies using an SPI Fluent API using a Builder

Historic Validity of currencies related to regions/countries and

vice versa

public interface CurrencyUnit{

public String getCurrencyCode();

}

API

public final class MoneyCurrency {

public String getCurrencyCode();

public int getNumericCode();

public int getDefaultFractionDigits();

}

RI

*not part of RI



Usage Samples MoneyCurrency

MoneyCurrency currency1 = MoneyCurrency.of("USD");

MoneyCurrency currency2 = MoneyCurrency.of("1234");

MoneyCurrency.Builder builder = new MoneyCurrency.Builder();

builder.setCurrencyCode("BTC");

builder.setDefaultFractionDigits(8);

MoneyCurrency bitcoin = builder.build();

15

• Access a MoneyCurrency

• Create a MoneyCurrency

• Register a MoneyCurrency

MoneyCurrency bitcoin = builder.build(true);


Monetary Amounts

General Aspects

16

Amount = Currency + Numeric Value

Performance vs. Precision and scale

Wide Numeric Range

Rounding, non standard Rounding

Financial Calculations and Functions

ME Compatibility

Fluent API

Go for the money - JSR 354 - http://java.net/projects/javamoney

Original Rounded Remark

123.452 123.45 3. digit <3 -> round down

123.456 123.455 3<= 3. digit <=7 -> change to 5

123.459 123.46 3. digit >=8 -> round up

23th October 2013

Monetary Amounts (continued)

Decisions

17

• Allow Several Numeric Representations

• Use functional design for extended functionality (MonetaryAdjuster, MonetaryQuery)

• Add Implementation Recommendations

• Rounding should to be modelled as separate concern (a MonetaryAdjuster)

• Interoperability by the MonetaryAmount interface

• Precision/scale capabilities should be inherited to its

operational results.

• …



API

public interface MonetaryAmount{

public CurrencyUnit getCurrency();

public long getAmountWhole();

public long getAmountFractionNumerator();

public long getAmountFractionDenumerator();

public MonetaryAmount with (MonetaryAdjuster adjuster);

public <T> T query(MonetaryQuery<T> query);

}

18

• Interface MonetaryAmount for Interoperability



RI: Money (based on BigDecimal)

public final class Money implements MonetaryAmount{


public Money add(MonetaryAmount amount);

public Money subtract(MonetaryAmount amount);

public Money multiply(MonetaryAmount amount);

public Money multiply(Number amount);

[…]

public boolean isGreaterThan(MonetaryAmount amount);

public boolean isLessThan(MonetaryAmount amount);

public boolean isLessThanOrEqual(MonetaryAmount amount);

[…]

public Money with (MonetaryAdjuster adjuster);


[…]

public BigDecimal asNumber();

[…]

public static Money from(MonetaryAmount amount);

}



RI: FastMoney (based on long)

public final class FastMoney implements MonetaryAmount{


public FastMoney add(MonetaryAmount amount);

public FastMoney subtract(MonetaryAmount amount);

public FastMoney multiply(MonetaryAmount amount);

public FastMoney multiply(Number amount);

[…]

public boolean isGreaterThan(MonetaryAmount amount);

public boolean isLessThan(MonetaryAmount amount);

public boolean isLessThanOrEqual(MonetaryAmount amount);

[…]

public FastMoney with (MonetaryAdjuster adjuster);


[…]

public BigDecimal asNumber();

[…]

public static FastMoney from(MonetaryAmount amount);

}



Usage Samples

Money amount1 = Money.of("USD", 1234566.15);

// USD 1234566.15

FastMoney fAmt = FastMoney.of("USD", 1234566.15);

// USD 1234566.15

Money amount1 = amount1.substract(fAmt);

MoneyCurrency currency = MoneyCurrency.of(“1234");

Money amount2 = Money.of(currency, 1234566.15);

// 1234 1234566.15

Amount2 = amount2.multiply(200)

.divide(0.5432)

.subtract(

Money.of("1234", 1234566.15));


Extension Points

javax.money


Extension Points

MonetaryAdjuster

A MonetaryAdjuster takes an amount and procudes some other amount. With different value With different currency Or both

public interface MonetaryAdjuster {

public MonetaryAmount adjustInto(MonetaryAmount amount);

}

Adjusters then can be applied on every MonetaryAmount:

public interface MonetaryAmount { …

public MonetaryAmount with (MonetaryAdjuster adjuster); … }


Extension Points (continued)

MonetaryAdjuster: Use Cases

Extend the algorithmic capabilities

• Percentages

• Permil

• Different Minor Units

• Different Major Units

• …

Rounding

Currency Conversion

…



MonetaryAdjuster: Usage Examples

25

MonetaryAdjuster rounding =

MoneyRoundings.getRounding(

MoneyCurrency.of(“USD”));

MontaryAmount myAmount = …;

MonetaryAmount rounded = myAmount.with(myAmount);

// MonetaryFunctions, e.g. calculate 3% of it

MonetaryAmount threePercent = rounded.with(

MonetaryFunctions.getPercent(3));



MonetaryQuery

A MonetaryQuery takes an amount and procuces an arbitrary result. public interface MonetaryQuery<T> {

public T queryFrom(MonetaryAmount amount);

}

Queries then can be applied on every MonetaryAmount:

public interface MonetaryAmount {

…

public <T> T query (MonetaryQuary<T> query);

…

}



MonetaryQuery: Usage Example

Predicates*, e.g. for usage in the JDK 8 Streaming API, can be implemented as MonetaryQuery:

public final class CHFAmountsOnly

implements MonetaryQuery<Boolean>{

private static final MoneyCurrency chf =

MoneyCurrency.of(«CHF»);

public Boolean select(MonetaryAmount amount){

if(amount.getCurrency().equals(chf)){

return Boolean.TRUE;

}

return Boolean.FALSE;

}

}

27

*not part of RI, but in the javamoney OSS project


Formatting and Parsing

MonetaryAmountFormat (Reference Implementation)

Similar to java.text.DecimalFormat.

With extended functionality for

currency placement

Number grouping

Enabling fluent API with builders

Example: MonetaryAmountFormat inrFormat = new

MonetaryAmountFormat.Builder(new Locale(“”, “in”))

.withNumberGroupSizes(3,4)

.build();

String formatted = inrFormat.format(

Money.of("INR", 123456789101112.123456)));

Result: INR 12,34,56,78,91,01,112.10



org.javamoney.*



General

During the JSR many features were discussed

And implemented

This ensured the design is powerful enough

Helped to consolidate discussions

But…

exceeeds a JSR scope

So we created an OSS project!


JavaMoney OSS Project (continued)

Currency Conversion (org.javamoney.conversion)

ExchangeRateType rateType = ExchangeRateType.of("EZB");

ConversionProvider convProvider =

MonetaryConversion.getConversionProvider(rateType);

// conversion is a MonetaryAdjuster

CurrencyConversion chfConversion =

convProvider.getConverter()

.getCurrencyConversion(MoneyCurrency.of("EUR");

Money chfAmount = …;

Money eurAmount = chfAmount.with(chfConversion);



Currency Services

Provide Access to Currency Meta-Data

• access currency namespaces

• access currencies within a namespace

• access of historic currency data related to regions

Support mapping of currencies

Region API

Provides a region hierarchy (region forest)

Unicode CLDR region tree

ISO 2-, 3-letter countries

Custom trees



Flexible Formatting API with token based format builder

Predicates API

Auto-Rounding values

Financial Calculations (ongoing)

Compound Values


Contact Details

JSR 354: http://jcp.org

Java.net Project: http://java.net/projects/javamoney GitHub Project (JSR and JavaMoney): https://github.com/JavaMoney/javamoney

JUG Chennai Adoption (TrakStok):

https://github.com/jugchennaiadoptjava/TrakStok Twitter: @jsr354


http://jcp.org/

http://java.net/projects/javamoney

https://github.com/JavaMoney/javamoney

https://github.com/JavaMoney/javamoney

https://github.com/jugchennaiadoptjava/TrakStok

Q & A


The End


JAZOON'13 - Anatole Tresch - Go for the money (JSR 354) !

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