Introduction

Abra is a Java-based persistence tool, which can be used to define business classes and their multi-tier mappings. We needed a light-weight persistence tool which would allow for simple xml based definitions, and take care of all the sql code and JDBC based sql-Java mapping.

This was accomplished by using an xml map-file to define classes across sql, xml, and Java. Later we added the idea of abstracted views of classes which could be useful to pass to and from different interface layers that might not want to pass around a big heavy object.

As much of this was used in different message-based systems the idea of content validation became important, and we realized that it might be nice to define the validations on a particular field, or set of fields within a class, in the same place. Thus grew the map-file as it is today: a simple persistence layer with some extensions to allow for a centralized repository of business information driving generated mapping and validating code.