Research And Implement Of CORBA Valuetype Specification

The basic method of passing objects, in the architecture of CORBA, is by passing object reference. By passing object reference, it avoids system and communication costs of passing complicated objects and implements the distraction of clients and servers. In most situations, it is effective and reasonable. With the development of distributed application and CORBA specifications, in CORBA 2.3 object by value was introduced and in CORBA 2.4.2 the keyword'valuetype'was formally added to implement object by value. With object by value, those lightweight objects concentrate on data encapsulation and simple logic, especially in receiver read-only applications, client running efficiency will be greatly improved while server resources and network costs reduced largely. In addition, with object by value, CORBA and JAVA distributed model can be connected seamlessly, so does the co-operation of object passing. Our work is to research and propose a practical method of object by value, and augment keyword'valuetype'in IDL C++ compiler of ORBUS to support object by value. On the base of deep study of CORBA valuetype specification and ORBUS with its IDL compiler theory and structure, this paper proposed a workflow of implementing valuetype in CORBA system and its working mechanism. It deeply analyzed the augmentation of compiler pe-veral and syntax in implementation and back compiler map. In back compiler mapping, the paper researched different mapping-specification situations in detail respectively according to valuetype specification characteristics. According to the data member, operation, value-box, inheritance, valuetype coding/decoding and interface passing valuetype, we designed a different implement method and workflow.Secondly, according to the research of the characteristics of valuetype and LC local consensus protocol, this paper proposed valuetype object replica consensus algorithm based on improved LC and client TTL. It not only exceeds the valuetype specification, but also augments the application scope of valuetype. With our improved LC+TTL algorithm, on the one hand, the object replica consistency can be insured in limited time; on the other hand, system scalability can be greatly improved to adapt to large-scale applications.Finally, on the base of IDL C++ of ORBUS platform, we augmented valuetype to support object by value. With system test, we improved the feasibility and correctness of implementing valuetype in CORBA system.