COM Components and Objects

The CML uses five custom objects on the server (business-services tier) and one on the client (user-services tier). Some of these are Component Object Model (COM) components: Admin, Search, and User are instantiated on the Web server, and UserInfo is instantiated on the client. Two others are objects used internally only, MTSEnvironment and TableQueue. To view the code that creates and uses these objects, see CML ASP Source Files and CML Visual Basic Source Files.

Summary of the COM Components and Objects Used by the CML Application

• The Admin object is used for managing users and library materials.
• The Search object serializes search strings submitted by users so that Index Server can understand them.
• The User object performs tasks for library users related to the processing of requests for library materials.
• The TableQueue object controls the creation and deletion of user requests in the queue of requests for library materials. The object also queries information in the database, such as a given request's position in the waiting list and the number of available items on a topic. Lastly, the TableQueue object is also used to cancel a request for a library item.
• The MTSEnvironment object is an instantiation of a PRIVATE wrapper class used internally by other CML objects. The CML MTSEnvironment object is easy to use and encapsulates the details of creating components within MTS.
• The UserInfo object is the only object that resides on the client computer. It provides information about the library user to other parts of the CML application.