Corba Portable Object Adapter Research And Design

Nowadays OMG CORBA has been the primary solution for application integration in heterogeneous environment. Through broadly used in large scale distributed application ,such as telecommunication management and military simulation,CORBA was found to have certain flaws in its former object adaption model of the server side in CORBA 2.0 specification,which is called BOA (Basic Object Adaptor). So POA (Portable Object Adaptor) was introduced by OMG in CORBA Specification 2. 2 as a solution to BOA' s importability of server code. POA does improve the portability and quality of CORBA' s distributed object model,and provide more efficient support for critical application.This thesis first gives a profounded study on POA' s model and mechanism based on CORBA Specification 2. 3. After a brief analysis of what is in POA Specification and what is for implementation,I focous my design and implementation on several key problems of supporting efficient object access in POA,especially in the context of multi-thread ORB. These issues include: Design of POA and ORB core correlation. Our implementation of POA/ORB correlation can locate object quickly and provide request flow control by POAManager as well. Special dispatch policies are introduced to support request-level dispatching on POA. Consistency management in multi-thread context. The combination of mutex lock and request counting is used to maintain the sychronization of POA' s states . Optimization of collocated object invocation. Besides hash technique used for normal object adaption,more effective means is carried out for in-process object invocation. There are three choices of optimization ,which provide different trade-off levels between the efficiency and sematics of CORBA object invocation.This thesis takes the StarBus 3. 0 project of Network and Security Institute in CS School of NUDT as the background. All the issues discussed in the thesis are practised in the design and implementation of StarBus 3.0.