Convert numbers from digital format to words.

This code provides a tool to convert a number from its digital value to the words format. This release supports 3 built-in languages : English, French and Arabic.

Number x = 192345009;
NumberInWords numberInWords = new NumberInWords(x, Locale.ENGLISH);
System.out.println(numberInWords.toString());

one hundred ninety two million, three hundred forty five thousand, nine

The decimals are supported too :

double value = 200.0098;
NumberInWords numberInWords = new NumberInWords(value);
System.out.println(numberInWords.toString());

two hundred and zero zero ninety eight

If a customization is wanted, it will be by extending the Rules class and implement its method, the way the words format of a number is wanted. Then, the new Extended Rules will be registered for a locale, if it depends on a Region or a Language :

LocalesRulesRegistry.register(Locale.XXXX, new MyNewRules());

Or simply create a number by providing the new Rules :

NumberInWords numberInWords = new NumberInWords(29, new MyNewRules());

Test are written in order to maintain the coverage of all the rules that implemented, but not to cover all the possible cases.

Coverage is ensured to be 100% on branches, lines, and methods.

• Some limitations are found, due to the big numbers, if a million multiple in a such rank does not exist, it will be replaced by 10^{rank}.
• Decimal numbers beyond 10^15 are recommended to be dealt with as String not with double, because the decimal part is lost when converting it to BigDecimal

String x = "1000000000000000.001";
NumberInWords numberInWords = new NumberInWords(x);
String toLetters = numberInWords.toLetters();

This will yield

one quadrillion and zero zero one

Whereas

double x = 1000000000000000.001;
NumberInWords numberInWords = new NumberInWords(x);
String toLetters = numberInWords.toLetters();

Will yield

one quadrillion

The conversion can be used without needing to create an instance for each number, which is useful for the dependency injection oriented architectures :

Rules frenchRules = LocalesRulesRegistry.get(Locale.FRANCE);
INumberToWordsConverter numbersToWordsConverter = new NumberToWordsConverter();
String numberInWords = numbersToWordsConverter.convert("1500", frenchRules);
System.out.println(numberInWords);

mille cinq cents

FR : Noms_des_grands_nombres

EN : Names_of_large_numbers

EN : List_of_Illion_numbers