Using internationalization

Depending on your needs, you may need to use translated messages in different languages. By default the Void Framework provides a ResourceBundle based implementation. If your needs require more advanced management or different storage (ie: DB rather than files), you can easily use your own implementation.

To enable this module, just add following lines to the pom.xml file of your project.

<dependency>
    <groupId>dev.voidframework</groupId>
    <artifactId>voidframework-i18n</artifactId>
    <version>1.16.0</version>
</dependency>

Defining messages

Translations should be placed in a file named messages_<LANG>.properties (ie: messages_en.properties) in the resources directory.

resources/messages_fr.properties

lang.fr=Français

resources/messages_en.properties

lang.fr=French

Retrieving messages

The retrieval of translated messages is done through the use of the Internationalization service.

Example

public final class InternationalizationExample {

    private final Internationalization i18n;

    @Inject
    public InternationalizationExample(final Internationalization i18n) {
        this.i18n = i18n;
    }

    public void i18n() {
        // Output: Français
        i18n.getMessage(Locale.FRENCH, "lang.fr");

        // Output: French
        i18n.getMessage(Locale.ENGLISH, "lang.fr");
    }
}

Plural forms

The plural form can be handled in two ways, the first uses ChoiceFormat which allows via an advanced syntax to add some intelligence to the translation messages. The second, more simple, is based on the use of new keys with special naming.

Read more about ChoiceFormat on official Java documentation.

Example (ChoiceFormat)

key=This element contains {0,choice,0#no comments|1#one comment|1<{0,number,000} comments}

public void i18n() {
    // Output: This element contains 0 comments
    i18n.getMessage(Locale.ENGLISH, "key", 0);

    // Output: This element contains 1 comment
    i18n.getMessage(Locale.ENGLISH, "key", 1);

    // Output: This element contains 1337 comments
    i18n.getMessage(Locale.ENGLISH, "key", 1337);
}

Example (New key)

inbox.0=Inbox "{0}" contains no messages
inbox.1=Inbox "{0}" contains one message
inbox.2=Inbox "{0}" contains {1} messages

public void i18n() {
    // Output: Inbox "Unread" contains no messages
    i18n.getMessage(Locale.ENGLISH, 0, "inbox", "Unread", 0);

    // Output: Inbox "Unread" contains one message
    i18n.getMessage(Locale.ENGLISH, 1,"inbox", "Unread", 1);

    // Output: Inbox "Unread" contains 42 messages
    i18n.getMessage(Locale.ENGLISH, 42, "inbox", "Unread", 42);
}