Spring MessageSource ICU With Yaml Support

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

• YAML resources for the messages sources.

• Simple base MsgService interface that's independent of any framework, makes it easy to use in libraries and then share across spring, grails and micronaut etc...

• Allows placeHolder replacement. So a message can look like

  company: Yakworks
  hello: Hey {name}, from ${company}
  

  then msgService.get('hello', [name: 'Bob']) == 'Hey Bob, from Yakworks'

Usage

While some of the helpful classes are using groovy, groovy is not required to the bulk of the core functionality

SpringBoot

Gradle deps:

implementation 'org.yakworks:spring-icu4j:0.3.0'

Define the bean.

// override the default messageSource bean, simple example, might want to build further
@Bean
public ICUMessageSource messageSource() {
    DefaultICUMessageSource messageSource = new DefaultICUMessageSource();
    messageSource.setBasename("messages");
    return messageSource;

Place your messages.yaml (or messages.properties) files under src/main/resources. See this projects test cases for some examples.

Grails 4.x +

`implementation 'org.yakworks:grails-icu4j:0.3.0'

messageSource bean will be setup and overrides the default. Should be fully backword compatible.

Works with messages.properties or messages.yaml in grails-app/i18n. Can also place your message files under src/main/resources.

Grails External Properties

can set 2 config properties

yakworks.i18n.externalLocation="'file:///app/external-resources'

to set how long to cache yakworks.i18n.cacheSeconds=60

Project layout and running tests

can use make check or ./gradlew check to run the full monty

• spring dir is for the spring source
• grails dir depends on spring project and is for plugin
• i18n is for the yakworks.i18n common model files such as 'MsgKey' class that dont require spring or grails to compile

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}
user.status={username}, you have {unread} unread messages of {total}

Exmaple with this lib:

Map args = [username: "John", unread: 12, total: 200)
println messageSource.getMessage("user.status", args)

->John, you have 12 unread messages of 200

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 Object[]{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 MessageSource vs ICUMessageSource

While yakworks.i18n.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 ICUMessageSource#getMessage

Yaml

• https://github.com/akkinoc/yaml-resource-bundle
• https://stackoverflow.com/questions/43655895/spring-boot-yml-resourcebundle-file
• https://gist.github.com/composite/eb3a3fd85d7ba9891f860e4a9fed06b9