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Latest revision as of 12:21, 29 January 2008

1 Eclipse Globalization Guidelines

Eclipse Globalization Guidelines

This document is a working draft.
Kit Lo
Last Updated: January 29th, 2008
Note: Please use Babel committers mailing list to add comments instead of embedding them in this document.

Introduction

Eclipse is an open source project contributed by developers around the world. Every developer’s programming style may be a little different. Often times, developers may not aware that little things they do in their programs may have a huge impacts in globalization of Eclipse. In this document, we try to define a set of guidelines for Eclipse globalization. If these guidelines are adopted by all Eclipse developers and translators, it will lead to greater consistency and the success of globalizing Eclipse.

In this section, we will discuss the rationales behind some of the globalization guidelines. At the end of the document, a summary of the Eclipse Globalization Guidelines is listed.

Eclipse Resource Bundle Process

Standard Java resource bundles are not very memory efficient. The keys for a resource bundle are stored in the class files of the plug-in, which are saved somewhere in the JVM’s data structures. The resource bundles are loaded in whole, even when no string is ever looked up from it.

Eclipse came up with an alternate resource bundle process in release 3.1 to improve memory usage. A conversion tool was provided to migrate to the new resource bundle process. See Message Bundle Conversion Tool for more information.

Locale specific files

There are three mechanisms for locating locale specific files in Eclipse:

Platform core mechanism (the platform's runtime locale-specific sub-directory search)

Java resource bundles (java.util.ResourceBundle)

The plugin.properties mechanism (Translating values from the plugin.xml files)

It is important to understand which mechanism is used to access any given file that must be translated so that you'll know what to name the file and where to put it in the file system relative to the plug-in.

Platform core mechanism
The platform core defines a directory structure that uses locale-specific subdirectories for files that differ by locale. (See Java 2 SDK, Standard Edition Documentation for the supported language codes and country codes.) Translated files are placed in a directory called nl under the plug-in. For example, the following install tree shows a trivial (no code) plug-in with locale-specific translations of its about.properties file. The various translations are shown as coming from a plug-in fragment rather than the plug-in itself. This is typical for shipping translations separately from the base, but you could also place the nl sub-directory under the plug-in itself.

acmeweb/
   eclipse/
     plugins/
      com.example.acme.acmewebsupport_1.0.0/
        plugin.xml
        about.properties    (default locale)
      com.example.acme.fragmentofacmewebsupport_1.0.0/
        fragment.xml   (a fragment of com.example.acme.acmewebsupport 1.0.0)
        nl/
          fr/
            about.properties  (French locale)
            CA/
              about.properties  (French Canadian locale)
            FR/
              EURO/
                about.properties (French France Euros)
          en/
            about.properties  (English locale)
            CA/
              about.properties  (English Canadian locale)
            US/
              about.properties (English US locale)
         de/
            about.properties (German locale)

The files to be translated are not contained in JAR files. Each file should have exactly the same file name, but be located in subdirectories underneath the nl sub-directory in the fragment's (or plug-in's) root.

Only the most specific file is accessed at runtime. The file paths are searched as part of the Platform.find, IPluginDescriptor.find and Plugin.find mechanism. For example, suppose the default locale is en_CA, and a plug-in searches for the about.properties as follows:

somePlugin.find("$nl$/about.properties");

The method will return a URL corresponding to the first place about.properties is found according to the following order:

com.example.acme.acmewebsupport_1.0.0/nl/en/CA/about.properties

com.example.acme.fragmentofacmewebsupport_1.0.0/nl/en/CA/about.properties

... <any other fragments>

com.example.acme.acmewebsupport_1.0.0/nl/en/about.properties

com.example.acme.fragmentofacmewebsupport_1.0.0/nl/en/about.properties

...

com.example.acme.acmewebsupport_1.0.0/about.properties

com.example.acme.fragmentofacmewebsupport_1.0.0/about.properties

This mechanism is used by plug-ins to search for well known file names inside other plug-ins. This includes the following well known file names:

preferences.properties (externalized strings for plug-in -specific preference default overrides)

about.properties (externalized strings for feature "about" information)

plugin_customization.properties (externalized strings for product-specific preference default overrides)

splash.bmp (product-specific splash screens)

(Note: The plugin.properties and fragment.properties are conspicuously absent from this list. They are treated in a sightly different way described below.)

Java resource bundles
The standard Java handling of property resource bundles is used for other files. Translated files are contained in a JAR file, with each properties file having a locale-specific name, such as "message_en_CA.properties". The files are in package-specific subdirectories and may appear in the plug-in itself or one of its fragments. Each translated properties file may be partial since lookup of keys accesses a well-defined chain of properties files.

The plugin.properties mechanism
The mechanism used to translate plugin.properties files uses the Java resource bundles naming convention. However the files must be located in the root of the plug-in or in the root of a fragment of this plug-in. The same rules apply to the translation of MANIFEST.MF.

All ResourceBundle file contents should be encoded in UTF-8

Different operating systems running in different language settings may save files in different encodings. To avoid confusions, we recommend all Eclipse developers and translators to encode all ResourceBundle source file contents and all translated ResourceBundle file contents in UTF-8.

Guideline 1.1

All ResourceBundle source file contents should be encoded in UTF-8.

Guideline 2.1

All translated ResourceBundle file contents should be encoded in UTF-8.

Single Quote Handling

Depending on whether the code will process the message string through the Java MessageFormat class, single quotes in ResourceBundle files should be written differently. If the string will be processed by MessageFormat, then any single quote in the string must be doubled. Otherwise, a single quote should not be doubled. Translators who do not have access to the code cannot tell if the message string would be processed by MessageFormat.

Most Java programmers follow the model of processing the message string with MessageFormat only if the message string contains replacement variables. We recommend all Eclipse developers to follow these guidelines when creating message strings and writing the code to process the message strings:

Strings which contain replacement variables are processed by the MessageFormat class (single quote must be coded as 2 consecutive single quotes).

Strings which do NOT contain replacement variables are NOT processed by the MessageFormat class (single quote must be coded as 1 single quote).

Guideline 1.2

Process message string with Java MessageFormat class only if the message string contains replacement variables.

Here are examples of messages strings in ResourceBundle file and expected text displayed to end user:

ResourceBundle file:
String_1 = No variable. 1 quote (') 2 (''), 3 ('''), 4 ('''').
String_2 = Variable {1}. 2 quotes(''), 4 ('''').

Text displayed to end user:
String_1 => No variable. 1 quote (') 2 (''), 3 ('''), 4 ('''').
String_2 => Variable xxx. 2 quotes('), 4 ('').

Non-translatable Message Strings

Special comments may be added to force all text between the start and end tags to be non-translatable. The comments must start in column 1 and must contain this exact format:

ListResourceBundles:
Start comment: // START NON-TRANSLATABLE
End comment: // END NON-TRANSLATABLE

PropertyResourceBundles:
Start comment: # START NON-TRANSLATABLE
End comment: # END NON-TRANSLATABLE

Guideline 1.3

Enclose non-translatable message strings with special comments.

Prevent Fragmentation of Messages

Messages tend to occupy much storage space. It is only natural that developers try to economize the storage requirement by using some truly inventive techniques, such as, using English phrases or parts of words as building blocks for complete messages. However, if the final form of a message relies on the composition of several parts, that message may not be translatable at all. Translation can change the order of parts of speech, and words can acquire different forms depending on the context.

Guideline 1.4

Do not construct sentences from parts of sentences. Do not construct words from parts of words.

A phrase or word that can be inserted into several English messages may require a different case, gender, or plural ending when translated into other languages. The small amount of space saved cannot compensate for the confusion and trouble caused in translation.

Example 1: To report the operational status of the peripheral devices, a programmer creates the following two columns of terms:

Device	Status
Display	operational
Control unit	off line
Printer	busy
Serial port	defective

By selecting one item from each column, the product can generate 16 messages by just storing 8 terms. Two of these messages would be:

Display operational

Control unit operational

In French, however, the nouns display and control unit are of different gender, thus requiring different forms of the adjective operational:

Poste opérationnel

Unité de contrôle opérationnelle

Example 2: In English, the word day can be prefixed with the following word fragments to form the seven days of the week:

Sun

Mon

Tues

Wednes

Thurs

Fri

Satur

This technique, however, does not work in most other languages. In the table below, it will not work for Sunday in French and Wednesday in German.

English	French	German
Monday	Lundi	Montag
Tuesday	Mardi	Dienstag
Wednesday	Mercredi	Mittwoch
Thursday	Jeudi	Donnerstag
Friday	Vendredi	Freitag
Saturday	Samedi	Samstag
Sunday	Dimanche	Sonntag

Avoid using a slash to mean "and" or "or"

Avoid using a slash to mean "and" or "or" because it is ambiguous in English and does not exist in other languages.

Guideline 1.5

Do not use a slash to mean “and” or “or”.

Avoid forming plurals by adding "(s)" to indicate either singular or plural form

Avoid forming plurals by adding "(s)" to indicate either singular or plural form even when space is a problem (such as, in messages, headings, captions, tables, or art callouts). Other languages form the plural of a noun in many different ways. Include in your sentence either the singular form, the plural form, or both forms.

Guideline 1.6

Avoid forming plurals by adding "(s)" to indicate either singular or plural form.

Avoid abbreviations, acronyms, and special symbols

Abbreviations of words can lead to misunderstandings by the translators and by the readers. Rules for abbreviation vary from language to language. Never assume that translators can understand the meaning of your abbreviations or can abbreviate their translations similarly.

Guideline 1.7

Avoid abbreviations, acronyms, and special symbols.

If you must use an abbreviation or acronym, ensure that your translator knows its exact meaning, and that you allow enough space for the expression to be spelled out fully in other languages.

Example: North Americans use # for number, ' for feet or minute, " for inch or second, and c/o for care of. Other languages may not have such short form equivalents.