Kĩ thuật lập trình - Lecture 20: Distributed computing broker and middleware

Ivan MarsicRutgers UniversityLECTURE 20: Distributed ComputingBroker and Middleware1TopicsMiddlewareBroker Design PatternJava Remote Method Invocation (RMI)2Object Messaging via Middleware3Serialization / MarshallingFrom software objects to a sequence of bits for network transmission List SorterClientListMiddlewareMiddlewareNetworkComputer AComputer B0101100114MiddlewareMiddleware is a collection of objects that offer a set of services related to object communication, so that extraneous functionality is offloaded to the middlewareTo reduce the number of object’s responsibilitiesIn general, middleware is software used to make diverse applications work together smoothly56MiddlewareObject AObject BMiddlewareObject AObject B'Object A'Object B(a)(b)7Broker Pattern(a)(b)8Broker Class Diagram(c)9Client-Server RMI/RPC10Java RMI Example11Practical IssuesDo not design for patterns firstReaching any solution is the priority;solution optimization should be secondaryRefactor the solution to patternsE.g., to reduce the complexity of the program’s conditional logicUncritical use of patterns may yield worse solutions!12