Distributed ObjectsandAdvanced Remote Method Invocations课件.pptVIP

Testing and Debugging an RMI Application 1. Build a template for a minimal RMI program. Start with a remote interface with a single signature, its implementation using a stub, a server program which exports the object, and a client program which invokes the remote method. Test the template programs on one host until the remote method can be made successfully. 2. Add one signature at a time to the interface. With each addition, modify the client program to invoke the added method. 3. Fill in the definition of each remote method, one at a time. Test and thoroughly debug each newly added method before proceeding with the next one. 4. After all remote methods have been thoroughly tested, develop the client application using an incremental approach. With each increment, test and debug the programs. 精品文档 Comparison of the RMI and the socket APIs The remote method invocation API is an efficient tool for building network applications. It can be used in lieu of the socket API in a network application. Some of the tradeoffs between the RMI API and the socket API are as follows: The socket API is closely related to the operating system, and hence has less execution overhead. For applications which require high performance, this may be a consideration. The RMI API provides the abstraction which eases the task of software development. Programs developed with a higher level of abstraction are more comprehensible and hence easier to debug. 精品文档 A Sample Enterprise Application In the illustrated application, the object server provides remote methods which allows the object clients to look up or update the data in an Expense Records database. Programs which are clients of the object provide the application or business logic for processing the data and the presentation logic for the user interface which presents the data. 精品文档 To be continued The Java RMI facility is rich in features. This chapter has presented a very basic subset of those features, as an i