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Java localization best practices

Asked 2010-09-02T18:15:46.353
18

I have a Java application with server and Swing client. Now I need to localize the user interface and possibly also some of the data needs to be locale specific. There are few things in specific I would like to hear your opinions on.

  1. How should I distribute the localized strings for the UI into properties files? In my application there are several views and each has several panels. Should I have one localization file per language for each panel or view or should I keep all translations for one language in the same file? I'm currently leaning towards one file per view and language, but I'm not sure how I should handle some domain specific terms which appear in many places. Having the same translation on several files does not sound too good.
  2. The server throws some exceptions that contain a message that should be displayed to the user. I could get the selected locale from the session and handle the localization at the server, but I feel it would be more elegant to keep all localization files at the client. I have been thinking about sending only a localization key from the server with some kind of placeholders for error specific information, which would be sent with the exception. Then the client could construct the message based on the localization key and replace the placeholders with the error specific information. Does that sound like a good way to handle it, or are there other options? Typically my exception messages contain some additional information that changes for each case. It could be for example "A user with username Khilon already exists", in which case the string in the properties file would be something like "A user with username {0} already exists".
  3. The localization of the data is the area that is the most unclear to me. As I'm not sure if it will be ever required, I have so far not planned it very much. The database part sounds straightforward enough, you basically just need an additional table for
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Actually, what you are talking about is Internationalization (i18n), not Localization (L10n). From my experience, you are on the right path.

ad 1). One properties file per view and locale (not necessary language, as you may want to use different translations for certain languages depending on country, i.e. using different strings for British an American English thus different locales) is the right approach. Since applications tend to evolve, it could save a good deal of money when you want to modify just one view (as translators will charge you even for something they won't touch - they will have to actually find strings that need to be updated/newly translated). It would be also easier to use with Translation Memory tools if you do it right (new strings at the end of the file all the time).

ad 2). The best idea is to sent out only the resource key from server or other process; other approach could be attaching a resource key and possibly the data (i.e. numeric value) using delimiters, so the message could be recreated and reformatted into local language.

ad 3). I have seen several approaches to localizing Databases, but the best (and it is not only my opinion, but also IEEE members) is to store resource keys and recreate the data on client side using appropriate locale. Of course this goes for pre-installed data, if you let users to enter the data, other issues will arose... There is no silver bullet, one need to think what works best in his/her context. I would lean to including a foreign key column that will identify the language, but it really depends on kind of data that will be stored.

Unfortunately i18n doesn't end here, please remember about correctly formatting dates and numbers so that they will be understandable for people using your program. And also, if you happen to have some list of strings, the sorting order should also depend on locale (it's called collation). Sun used to have (now our beloved Oracle) has quite goo

answered 2010-09-02T19:01:03.167

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