Java Enterprise Best Practices

Use Standard Java Classes (Instead of Database Constructs) for Collation and for Sorting Database Information

Suppose you’ve properly configured your database to handle the localizations required by your application. As we mentioned in the previous section, the localization information contained within a database can be used to determine things such as the collation or sort order for data returned when the SQL ORDER_BY clause is used to retrieve data.

You might or might not be familiar with the standard Java libraries for collating data. Earlier, in Section 8.3.1, we mentioned the java.text package, which contains the classes that will allow you to control locale-based collation. In applications that you designed to be internationalization-ready, you rely on objects in the business object layer to control the collation and sorting of data. There are a number of reasons why this is advantageous over relying on your database to handle these operations for you.

First, the rules for collation and sorting within the database are typically not configurable. You rely on the operating system or database vendor to investigate the locales it supports to develop the proper rules for collation. However, these rules are not exposed from the database. By allowing your business object layer to perform locale-based collation, you can take advantage of classes such as java.text.RuleBasedCollator for fine-grained control over the rules for sorting.

Another reason is that although most databases ...