Abstract: A multi-tier server application architecture provides a simplified programming model of multiple user server applications that enhances programmer productivity. The multi-tier architecture comprises a client tier for client application code that initiates processing by the server application in response to user input, a middle tier of object-oriented server application code, and a database tier of shared access data and management code. A run-time environment for the object-oriented server application code limits access to instantiated objects of the middle tier server application code to a single one of the users. Objects in the middle tier that are instantiated to initiate processing for a particular user and grouped into a collection. The run-time environment manages the flow of execution into the collection such that the collection has only a single logical thread of execution and access by the client application code is exclusive to the particular user.

Abstract: A programming model for component-based server applications provides declarative and programmatic access control at development without knowledge of the security configuration at deployment. The developer defines the server application access control by defining logical classes of users, called roles. The developer also can declare access privileges of the roles at package, component and interface levels of the server application. At development, the roles are bound to the particular security configuration of the server computer. The programming model also provides application programming and integration interfaces with which the developer can programmatically define access control of the roles to the server application's processing services.

Abstract: A run-time environment implemented as system services and component integration interfaces provides a capability for components of a component-based server application to reversibly disable committal of a transaction in which the component participates. On return from a call to the component which leaves the component's transactional work in an invalid state, the component can disable commit of the transaction so as to avoid premature committal of the component's transactional work. On return from a call to the component which renders the component's transactional work in a valid state, the component re-enables commit of the transaction. If committal of the transaction is initiated when any component in the transaction disables commit, the transaction is aborted.

Abstract: A method and apparatus colors the conventional error codes of each word of a multiword transmission to facilitate the detection of words which are out of order or not part of the transmission, without affecting the data in the word. A 1-bit by n-bit matrix is assembled using the header word, and zeros for the header of the multiword transmission, or the data word, error code, if any, an identifier portion of the header word and zeros for each data word, and the 1-bit by n-bit matrix is multiplied by an n-bit by m-bit matrix assembled from a conventional error coding matrix and other matrices. The result either produces an error code to be sent with the header or data, or a check code to be verified as all zeros to indicate the absence of bit errors within the header or data word, and that the word is in the proper packet and in the proper sequence within the packet.

Abstract: A component-based framework includes system services and component integration interfaces that provide a run-time environment which automatically provides transactions to encompass work of component-based server applications according to the transactional expectations of individual server application components. A transaction attribute is associated with each server application component that represents whether the component requires execution in a transaction. When a client requests creation of a server application component without having first initiated a transaction and the component's transaction attribute indicates a transaction is required, the framework automatically initiates a transaction in which to run the server application component. The framework also completes the automatically initiated transaction upon receiving an indication from the server application component that its transactional work is complete.