i18n gettext (.pot, .po language files)

1 Reference

-gettext home > https://www.gnu.org/software/gettext/

-gettext maven plugin > https://github.com/rlf/maven-gettext-plugin/

2 Introduction

the GNU `gettext' utilities are a set of tools that provides a framework to help other GNU packages produce multi-lingual messages. These tools include a set of conventions about how programs should be written to support message catalogs, a directory and file naming organization for the message catalogs themselves, a runtime library supporting the retrieval of translated messages, and a few stand-alone programs to massage in various ways the sets of translatable strings, or already translated strings.

3 Maven config

Let's configure our Maven Java project for using PO files for language translation, the relevant project structure is:

src/main/resources/po/

                      en.po

                      es.po

                      pl.po

                      keys.po

pom.xml

The maven-gettext-plugin goal "dist" is used for generating Java ResourceBundle classes from .po files.

The following example will generate a Messages_xx.class file for every .po language file available:

<plugins>

   <plugin>

        <!-- https://github.com/rlf/maven-gettext-plugin/ -->

        <groupId>com.github.rlf</groupId>

        <artifactId>gettext-maven-plugin</artifactId>

        <version>1.2.10</version>

     <executions>

     <execution>

      <goals>

       <goal>dist</goal>

      </goals>

      <configuration>

       <javaVersion>2</javaVersion>

       <outputDirectory>${project.build.directory}/classes</outputDirectory>

       <outputFormat>class</outputFormat>

       <poDirectory>${basedir}/src/main/resources/po</poDirectory>

       <sourceLocale>en</sourceLocale>

       <targetBundle>ude.cou.pera.gettext.Messages</targetBundle>

      </configuration>

     </execution>

    </executions>

   </plugin>

</plugins>

4 Sample content for the keys.pot and es.po files

keys.pot:

#: Hello.java:14

msgid "Hello, world!"

msgstr ""

#: Hello.java:18, java-format

msgid "This program is running as process number {0}."

msgid_plural "These programs are running as process number {0}."

msgstr[0] ""

msgstr[1] ""

es.po:

# Mensajes en español para GNU gettext.

# Copyright (C) 2014 Yoyodyne, Inc. (msgids)

# This file is distributed under the same license as the gettext package.

# Max de Mendizábal <max@upn.mx>, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004.

# Antonio Ceballos <aceballos@gmail.com>, 2014, 2015

msgid ""

msgstr ""

"Project-Id-Version: hello-java-0.19.4.73\n"

"Report-Msgid-Bugs-To: bug-gnu-gettext@gnu.org\n"

"PO-Revision-Date: 2015-06-23 22:44+0200\n"

"Last-Translator: Antonio Ceballos <aceballos@gmail.com>\n"

"Language-Team: Spanish <es@tp.org.es>\n"

"Language: es\n"

"MIME-Version: 1.0\n"

"Content-Type: text/plain; charset=UTF-8\n"

"Content-Transfer-Encoding: 8bit\n"

"Plural-Forms: nplurals=2; plural=(n != 1);\n"

#: Hello.java:14

msgid "Hello, world!"

msgstr "¡Hola, mundo!"

#: Hello.java:18, java-format

msgid "This program is running as process number {0}."

msgid_plural "These programs are running as process number {0}."

msgstr[0] "Este programa se ejecuta con el número de proceso {0}."

msgstr[1] "EStos programas se ejecutan con el número de proceso {0}."

5 Example using the generated ResourceBundle classes

private static final String RESOURCE_BUNDLE = "ude.cou.pera.gettext.Messages";

String langCode = "pl";

ResourceBundle resourceBundle = ResourceBundle.getBundle(RESOURCE_BUNDLE, new Locale(langCode));

LOGGER.info("Locale language : " + resourceBundle.getLocale().getLanguage());

LOGGER.info("Locale country : " + resourceBundle.getLocale().getCountry());

String resource = GettextResource.gettext(resourceBundle, "Hello, world!");

LOGGER.info("Translated is : " + resource);

6 Troubleshooting

Plugin "gettext-maven-plugin" does not execute in an Openshift environment.

No solution was found for this issue, alternative was moving to XLIFF file format (see another article in this site).