Write numbers in words

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.

Using as instance

Basic Example :

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

Decimal Format :

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

Customization

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());

Testing And Coverage

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.

Limitations

• 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

Usage a stateless Service

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

References

FR : Noms_des_grands_nombres

EN : Names_of_large_numbers

EN : List_of_Illion_numbers