Enterprise JavaBeans, Third Edition

CTMs and Server-Side Component Models

CTMs require that business objects adhere to the server-side component model implemented by the vendor. A good component model is critical to the success of a development project because it defines how easily an application developer can write business objects for the CTM. The component model is a contract that defines the responsibilities of the CTM and the business objects. With a good component model, a developer knows what to expect from the CTM, and the CTM understands how to manage the business object. Server-side component models are great at describing the responsibilities of the application developer and CTM vendor.

Server-side component models are based on a specification. As long as the component adheres to the specification, it can be used by the CTM. The relationship between the server-side component and the CTM is like the relationship between a CD-ROM and a CD player. As long as the component (CD-ROM) adheres to the player’s specifications, you can play it.

A CTM’s relationship with its component model is also similar to the relationship the railway system has with trains. The railway system manages the train’s environment, providing alternate routes for load balancing, multiple tracks for concurrency, and a traffic-control system for managing resources. The railway provides the infrastructure on which trains run. Similarly, a CTM provides server-side components with the entire infrastructure needed to support concurrency, transactions, ...