Software Architectures for Integrating Clients, Servers, Legacy, Database, and COTSProf. Steven A. DemurjianDept. of Computer Science & EngineeringThe University of ConnecticutStorrs, CT 06269-3155AbstractTable of Contents1. Introduction2. Architectural Alternatives3. Integrating a C++ Legacy Application with Java3.1 The ADAM Software Architecture3.2 Client Requirements and Functionality3.3 Wrapper Requirements and Functionality3.4 Communications Requirements and Functionality3.5 TwinPeaks Requirements and Functionality3.6 Incorporation of CORBA4. Assessing the Impact and Importance to EC5. Concluding Remarks and Future WorkReferencesSoftware Architectures for Integrating Clients, Servers,Software Architectures for Integrating Clients, Servers,Legacy, Database, and COTSLegacy, Database, and COTSCSE Technical Report CSE TR-02-99Prof. Steven A. DemurjianProf. Steven A. DemurjianDept. of Computer Science & EngineeringDept. of Computer Science & EngineeringThe University of ConnecticutThe University of ConnecticutStorrs, CT 06269-3155Storrs, CT 06269-3155AbstractAbstractEnterprise computing (EC) is the recognition that to effectively utilize and disseminateinformation within an entity (university, corporation, government agency, etc.) it will benecessary to design and develop integrated distributed computing environments thatallow all types of existing and future systems to interoperate. In EC, there are legacy,COTS, database, and new client/server applications that all must interact to facilitate bothpeace and war time communications among personnel at various locations. To allowthese different applications and systems to interoperate, a number of approaches can beapplied that translate to a common framework. Possibilities for such a commonframework could range from very low level (e.g., assembly) to low level (e.g., C/C++and RPC) with existing technologies. When emerging technologies are considered, onecan choose among new object-oriented programming technologies (e.g., Java and itsEnterprise Computing API), database systems (e.g., Jasmine), or distributed objectcomputing paradigms (e.g., CORBA, DCE, DCOM/OLE, etc.). This paper exploressoftware architectural alternatives for integrating the clients, servers, legacy/COTS, anddatabases that comprise EC applications. The emphasis of the work is to report on ourpractical experiences in upgrading a C++ legacy application to be Java compatible. Table of ContentsTable of Contents1. Introduction2. Architectural Alternatives3. Integrating a C++ Legacy Application with Java 3.1 The ADAM Software Architecture 3.2 Client Requirements and Functionality 3.3 Wrapper Requirements and Functionality 3.4 Communication Requirements and Functionality 3.5 TwinPeaks Requirements and Functionality 3.6 Incorporation of CORBA 4. Assessing the Impact and Importance to EC5. Concluding Remarks and Future Work11.1.IntroductionIntroductionDistributed computing environments for the 21st century will require designers anddevelopers to architect solutions that facilitate the interoperation of new and existingapplications. In ECA, a system of systems must be constructed, consisting of legacy,COTS, database, and new client/server applications that must interact to communicateand exchange information between users in peace and war-time settings. However, thereis a larger purpose to solving the enterprise computing problems of integratedapplications. The issue is not simply to provide a means to allow different systems tointeract and exchange information, but rather to promote the use of existing applicationsin new and innovative ways in a distributed environment. In the enterprise computingenvironment, an existing legacy/COTS application can be extended in a variety of ways,including: an expansion with multi-user capabilities; the incorporation of a new graphicaluser interface (GUI) that employs modern tools; or, the addition of new functionality thatadds value and increases capabilities.To address enterprise computing problems and solutions for applications, the field ofsoftware architectures can be utilized. Software architectures [Shaw96] expandstraditional software engineering by looking at how different major system componentscan mesh and interact. ECA, as a system of systems, is particularly suited to anarchitectural approach, to clearly and definitively specify the interactions between thelegacy, COTS, databases, clients, and servers. Software architectures is an emergingdiscipline whose intent is to force software engineers to step back from their traditionalalgorithm/data structure perspective and view software as a collection of interactingcomponents. Interactions occur both locally (within each component) and globally(between components). In understanding interactions, the key consideration is to identifythe communication and synchronization requirements which will allow the functionalityof the system to be precisely captured. By taking a broader view of the problemdefinition process, software architectures permits database needs, performance/scalingissues, and security requirements, to be considered, all of which are critical for ECA. Enterprise computing solutions using software architectures are varied, and are oftendependent on application domain. In some applications, like a university, a softwarearchitectural solution that advocates a common framework might suffice. For example,unifying all of the systems at a university that involve scheduling, registration,transcripts, accounts, purchasing, etc., with new Web-based tools for faculty and studentsmay be feasible with a Java-wrapper solution. In such a solution, existing systems arewrapped with Java to achieve a common framework (via RMI, object-serialization, orCORBA) for interacting with new Java tools. In a university setting, performancedemands, life/death issues, or profit/loss considerations are not as pervasive whenintegrating new and existing systems. In other applications, performance, reliability,life/death issues, etc., are all critical, and may require the examination of wrapper-basedand other solutions to
View Full Document
Unlocking...