Package hirondelle.web4j.ui.translate

Translation of text for multilingual applications.

See:
Description

Interface Summary

Translator

Translate base text into a localized form.

Class Summary

Messages	Custom tag for rendering a MessageList.
Text	Custom tag for translating base language text (or a "coder key") into a localized form, and applying "wiki-style" formatting.
TextFlow	Custom tag for translating regular text flow in large sections of a web page.
Tooltips	Custom tag for translating TITLE, ALT and submit-button VALUE attributes in markup.
Translation	Model Object for a translation.
Translation.LookupResult	The result of Translation.lookUp(String, Locale, Map).

Package hirondelle.web4j.ui.translate Description

Translation of text for multilingual applications.

Last-Second Localization

WEB4J's goal is to make the task of changing a single-language application into a multilingual one as painless and as focused as possible, with minimal ripple effects. To support this idea, WEB4J has two main design goals :

• Model Objects, actions, and Data Access Objects should be exactly the same regardless of whether the application is multilingual or not.
• Markup in a multilingual application should appear almost the same as in a single language application.

To achieve the first goal, WEB4J uses a policy of "last-second localization", whereby translations are performed outside of normal code, and only in Java Server Pages, using custom tags. This corresponds to the idea that a translation is "just a view".

Overview

The various items are :

• LocaleSource defines how an application deduces a Locale from an incoming request (using a policy defined by your application).
• the Locale obtained from LocaleSource is passed to a Translator, which defines how an application translates base text into a given target language.
• the Text tag uses the above to perform the translation "at the last second", in a JSP.
• the TextFlow tag translates all the text flow (the text appearing outside of tags) appearing in its body. This tag is suitable for translating large sections of markup whose text flow is simple and non-structured.
• the Tooltips tag translates all TITLE and ALT attributes appearing in its body (it also translates the text of SUBMIT buttons). If placed in a high-level template, it translates those attributes across a large number of pages - perhaps even the whole site.
• the Messages tag translates the AppResponseMessages emitted by Actions.

Translatable Items

Translatable items include :

• static text in a web page
• tooltips - the TITLE and ALT attributes of tags
• links whose target is dependent on Locale
• dynamic messages generated by the application

Suggested Development Style

For a new multilingual application, one may proceed as follows :

• start development with a do-nothing Translator, that simply returns the base text, unchanged and untranslated
• use the Text, Tooltips, TextFlow, and Messages tags during development, to internationalize JSPs from the beginning. (The text is not localized at this point.)
• when nearing completion, begin localization by changing the Translator implementation, to always record the base text in some way (save to the database, or to an in-memory List, for example). Thus, by simply exercising all parts of the application (including all possible error messages), one may generate a listing of all items that need translation.
• finally, translate all items, and provide the "correct" Translator implementation. (See the example application for illustration.)

If an existing application needs to be changed from a single-language style to a multilingual style, then a similar technique may be used.

Database versus ResourceBundle

Although a Translator may be backed by a ResourceBundle, the recommended style is to use a database instead. ResourceBundle is a mediocre tool for web applications.