Spring MessageSource ICU Support

Provides the ICU4J message formatting features, such as named arguments support, flexible plural formatting, rule based number format, date interval formats.

Features

Named arguments

By default Spring allows you to use only numbered arguments in i18n messages. ICU4j support named arguments using Map, which are sometimes are more readable. For example:

numbered={0}, you have {1} unread messages of {2}
names={username}, you have {unread} unread messages of {total}

With ICU4J, you can do this:

Map<String, Object> args = new HashMap<>();
args.put("username", "John");
args.put("unread", 12);
args.put("total", 200);

System.out.println(messageSource.getMessage("names", args, locale));

will output John, you have 12 unread messages of 200.

Plural formatting

Pluralisation in English is pretty simple and can be implemented using embedded ChoiceFormat. However, many other languages have more complex pluralisation rules described here, which cannot be handled by default. The plugin provides a simple pluralization using a language's rules, e.g. for Polish:

plural={0} {0, plural, one {auto} few {auta} many {aut} other{aut}}

System.out.println(messageSource.getMessage("plural", new Object[]{3}, locale));
System.out.println(messageSource.getMessage("plural", new Object[]{7}, locale));

will output 3 auta, 7 aut.

Rule based number formatting

amount={0, spellout} dollars

System.out.printlin(messageSource.getMessage("amount", new Objcet[]{12045}, locale));

will output twelve thousand forty-five dollars.

Other features

• ICU implements a more user-friendly apostrophe quoting syntax. In message text, an apostrophe only begins quoting literal text if it immediately precedes a syntax character (mostly {curly braces}). By default an apostrophe always begins quoting, which requires common text like "don't" and "aujourd'hui" to be written with doubled apostrophes like "don''t" and "aujourd''hui".
• Many more date formats: month+day, year+month,...
• Date interval formats: "Dec 15-17, 2009"

Spring Boot Usage

Define the bean.

@Bean
public MessageSource messageSource() {
    ICUReloadableResourceBundleMessageSource messageSource = new ICUReloadableResourceBundleMessageSource();
    messageSource.setBasename("classpath:messages");
    return messageSource;
}

Place your message.properties files under src/main/resources. See this projects test cases for some examples.

Explanation

While com.transferwise.icu.ICUMessageSource defines methods that take a named argument map, org.springframework.context.MessageSource does not. Therefore, in order to support ICU in code that expects a org.springframework.context.MessageSource message source, such as Thymeleaf's #messages, we check if the first argument of the Object[] args parameter passed to org.springframework.context.MessageSource#getMessage is a Map and if so cast that argument to a Map<String, Object> and call com.transferwise.icu.ICUMessageSource#getMessage

See com.transferwise.icu.ICUAbstractMessageSource.isNamedArgumentsMapPresent

License

This library is available under the Apache License, Version 2.0.

(c) All rights reserved