Internationalization - e-ucm/ead GitHub Wiki

We use the common Java convention of having several .properties files that provide localized strings for each visible need. These files are loaded and managed by the I18N class, which is part of the engine-core model (and is therefore available in all engine and editor flavors).

General use

The default localization language is Spanish; therefore, assets/i18n/messages.properties contains lines such as

editor.title = Editor de eAdventure

The English localization is found in assets/i18n/messages-en.properties, and contains, among many others, this variant:

editor.title = eAdventure Editor

From the actual Java code, these are called as follows:

frame.setTitle(I18n.m("editor.title"));

Advanced usage

Messages can be parametrized. For example, say that you want to describe the dimensions of a room. You would have, in the English .properties file,

room.dimensions = The {} room has a size of {}x{} paces.

And then, from the Java code, you would populate this via

showMessage(I18n.m("room.dimensions", "throne room", 10, 20));
// results in 'The throne room has a size of 10x20 paces'

That is, each successive instance of {} is replaced by the corresponding method parameters.

For the case when the messages differ depending on the cardinality of the input, a third version of I18N.m is available:

room.guards-singular = There is {} guard patrolling the {} exit.
room.guards-plural = There are {} guards patrolling the {} exit.

showMessage(I18n.m(room.guardNumber, "room.guards-singular", "room.guards-plural", room.guardNumber, "East"));
// results in 'There is 1 guard patrolling the exit' or 'There are 2 guards patrolling the exit' (for n != 1)

Adding new translations

Just drop a new .properties file in assets/i18n with the appropriate language-code; for example, for Swedish (sv), you would create a messages-sv.properties file, and add translations for all the strings found in the other properties files (the default Spanish and the English translations will always be the most up-to-date, as they are maintained directly by the development team).

Make sure that the new language is listed in assets/i18n/i18n.properties -- and if not, add it. This file is checked during application startup to populate language-selection menus. Having more languages listed than necessary has a minimal impact on application startup times, but is otherwise not a problem.