3. Standard Resources / ResourcesFactory Implementations

Commons Resources ships with the following implementations of Resources and ResourcesFactory provided:

The following sections describe how to use these implementations:

• 3.1 Property Resources
• 3.2 XML Resources
• 3.3 JDBC Resources
• 3.4 Web Application Property Resources
• 3.5 Web Application XML Resources
• 3.6 java.util.ResourceBundle Resources
  

3.1 Property Resources

PropertyResources wrap a family (one per Locale) of properties files that share a base URL and have name suffixes reflecting the Locale.

Resources are looked up in a hierarchy of properties files identical to that performed by java.util.ResourceBundle. For example, if the configuration URL is passed as file:c:/myapp/foo/Bar, then...

N.B. PropertyResources assumes all files will end with .properties

In these properties files, you specify key/value pairs in the normal way, for example...

     error.date=Date is invalid.
     error.number=Number is invalid.

To use PropertyResources, you create it using it's factory and then use in the normal way...

       // Create the ResourcesFactory
       ResourcesFactory factory = new PropertyResourcesFactory();

       // Create the Resources
       Resources resources = factory.getResources("Bar", "file:c:/myapp/foo/Bar");

       // Retrieve an i18n String value
       String msg = resources.getString("some.key", locale, null);

See PropertyResources JavaDoc /
source and PropertyResourcesFactory JavaDoc / source.

3.2 XML Resources

XMLResources works in pretty much the same way as PropertyResources, except the files are in XML format and XMLResources assumes a .xml file extension. Using the same example, if the configuration URL is passed as file:c:/myapp/foo/Bar then... ...

In these XML files, you specify resources in the following way...

     <resources>
           <resource id="error.date">
                 Date is invalid.
           </resource>

           <resource id="error.number">
                 Number is invalid.
           </resource>
     </resources>

To use XMLResources, you create it using it's factory and then use in the normal way...

       // Create the ResourcesFactory
       ResourcesFactory factory = new XMLResourcesFactory();

       // Create the Resources
       Resources resources = factory.getResources("Bar", "file:c:myapp/foo/Bar");

       // Retrieve an i18n String value
       String msg = resources.getString("some.key", locale, null);

See XMLResources JavaDoc /
source and XMLResourcesFactory JavaDoc / source.

3.3 JDBC Resources

JDBCResources retrieves messages from a database using JDBC. The table you use to store the messages needs three columns containing:

• the locale value (e.g. "en_US" for US English)
• the message key
• the message text
  

The names of these columns and the table is configured, along with the Driver information, in a JDBC Properties file. For example in c:/myapp/foo/Bar.properties...

        jdbc.connect.driver   = org.gjt.mm.mysql.Driver
        jdbc.connect.url      = jdbc:mysql://localhost/MyDatabase
        jdbc.connect.login    = MyUserName
        jdbc.connect.password = MyPassword

        jdbc.sql.table         = MyMessages
        jdbc.sql.locale.column = locale_key
        jdbc.sql.key.column    = message_key
        jdbc.sql.val.column    = message_text

N.B. JDBCResources appends .properties to the URL you supply for this file.

To use JDBCResources, you create it using it's factory, with the URL for the JDBC Properties file and then use in the normal way...

       // Create the ResourcesFactory
       ResourcesFactory factory = new JDBCResourcesFactory();

       // Create the Resources
       Resources resources = factory.getResources("Bar", "file:c:myapp/foo/Bar");

       // Retrieve an i18n String value
       String msg = resources.getString("some.key", locale, null);

See JDBCResources JavaDoc /
source and JDBCResourcesFactory JavaDoc / source.

3.4 Web Application Property Resources

WebappPropertyResources works the same way as PropertyResources, but in a Web Application environment. The only difference is you specify a context relative URL and you need to initialize the ServletContext....

       // Create the ResourcesFactory
       ResourcesFactory factory = new WebappPropertyResourcesFactory();
       factory.setServletContext(servletContext);

       // Create the Resources
       Resources resources = factory.getResources("Bar", "/org/apache/struts/Bar");

       // Retrieve an i18n String value
       String msg = resources.getString("some.key", locale, null);

See WebappPropertyResources JavaDoc /
source and WebappPropertyResourcesFactory JavaDoc / source.

3.5 Web Application XML Resources

WebappXMLResources works the same way as XMLResources, but in a Web Application environment. The only difference is you specify a context relative URL and you need to initialize the ServletContext....

       // Create the ResourcesFactory
       ResourcesFactory factory = new WebappXMLResourcesFactory();
       factory.setServletContext(servletContext);

       // Create the Resources
       Resources resources = factory.getResources("Bar", "/org/apache/struts/Bar");

       // Retrieve an i18n String value
       String msg = resources.getString("some.key", locale, null);

See Webapp{{`}}{{`}}XMLResources JavaDoc /
source and WebappXMLResourcesFactory JavaDoc / source.

3.6 java.util.ResourceBundle Resources

ResourceBundleResources is a Resources implementation that wraps a java.util.ResourceBundle instance.

       // Create the ResourcesFactory
       ResourcesFactory factory = new ResourceBundleResourcesFactory();

       // Create the Resources
       Resources resources = factory.getResources("Bar", "BarResources");

       // Retrieve an i18n String value
       String msg = resources.getString("some.key", locale, null);

See ResourceBundleResources JavaDoc /
source and ResourceBundleResourcesFactory JavaDoc / source.