INTRODUCTION

Applications in our context are defined as software that is developed by programmers to solve specific business problems. These applications generally implement business logic which is either not available in off-the-shelf applications, or some special constraints such as performance or security, which are otherwise not met by the COTS applications have to be considered.

Figure 3.1 describes the reference model for BSO. Our discussion in this chapter relates to developing software that resides in the Business Services tier and the tiers above it. Most orchestration products provide an orchestration engine, a sort of maestro, which reads the BSO definition and then manages the flow of activities. In some implementations, the orchestration engine as well as business logic code may execute inside a container environment. We discuss application and data services in this chapter as seen not only by the application containers but also by the orchestration container and the orchestration engine.

Products in this functional category, discussed in Section 5.2, relate to the Web application servers layer of the reference architecture presented in Chapter 3, Figure 3.1. Programming languages discussed in Section 5.3 are important for all layers of the reference architecture. Technologies discussed in Section 5.4 are again important for all layers in the reference architecture but relate more to the packaging protocols layer of the stack.

APPLICATION DEVELOPMENT PLATFORMS

An application development platform is a comprehensive set of services to develop, host, and manage applications. Any distributed application should be built using a robust application platform.