JEDMICS is a large image management system that is accessed by a number of heterogeneous client applications, which require access to the same image repository. The Open Application Interface (OAI) is a new API for providing client application developers with a unified interface to the image repository, thereby introducing a layer of abstraction between the end user and the physical storage layer of the data and metadata that make up the image management system.
This chapter describes and discusses the design and implementation of the JEDMICS OAI system, an EJB-based API (Enterprise Java Bean?based API) that provides access to image data that is stored on a variety of storage media and metadata stored in a relational database system. The main focus of the chapter is the use of XML as the portable data exchange solution, and its integration with the object-oriented core of the system and the relational database that forms the persistent storage. During the design and development of the OAI, we investigated the latest technologies and standards related to XML offered by different vendors, standards-governing, and user group communities (such as DOM, JDOM, JAXB, XSLT, Oracle XSU, etc.), to provide an effective solution for managing JEDMICS data. The chapter also presents our experiences with these technologies and standards, as well as the issues that we encountered while integrating them. We close this chapter by discussing the future directions of the OAI system.