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A model for Java / CORBA & OODBMS distributed architectures
| Content Provider | Semantic Scholar |
|---|---|
| Author | Mazzucchelli, Luigi |
| Copyright Year | 1999 |
| Abstract | The Java/CORBA paradigm extends distributively Java and allows to specify and implement multiplatform distributed object architectures. Such multi-client/server architectures, extended with Object Database Management Systems (OODBMS) as the principal persistent service, will become Object-Based Architectures (called OAs). The analysis and the use of dedicated techniques is required to specify and implement OAs, forcing us to challenge with the current design and development approaches. In this paper we introduce a model for such architectures that is based on a semantic distinction between ”Functional” objects and ”Data” objects. Functional Objects (FOs) are Java/CORBA (Client)Server distributed objects with well defined (standard) IDL interfaces, Data Objects (DOs) are FOs ”arguments”/”results” objects persistently stored in the OODBMS. The model relies on constructing a DOgraph, that is used for simple ”dataflow” centralized calling mechanism for FOs, and that is induced by correct typed composition of FOs. An example of concrete realization of such model is the implementation of the Text Retrieval and Enrichment for Vital Information (TREVI) distributed system for the analysis and categorization of natural language english texts (ESPRIT Project EP23311). 1. Java/CORBA & OODBMS distributed architectures The Java/CORBA approach gives to developers and to analysts the possibility to build reliable and efficient object based distributed products, and the Web view of the future global (and mobile) computing will even increase the globWork partially supported by the Project ”Tecniche Formali per la specifica, l’analisi, la sintesi e la trasformazione di sistemi software” of the MURST (Italian Ministero dell’Universit e della Ricerca Scientifica e Tecnologica) and by the TREVI European Research Project ESPRIT EP23311 ality of such language and middleware products. Java is now the ”stable” web based language and the CORBA infrastructure gives it the distributivity property: more and more applications (from real time systems to Web pages) are equipped with such technologies 1. 1.1. Object Based Architectures (OAs) The addition of Object Oriented Database Systems (OODBMS) will add an even more homogeneous vision and a logical uniformity to the object architectures. The architectural focus of such compound systems is on the structural and logical relation between well defined entities with complex processing dynamics. Let us call Object-Based Architecture (OA) a distributed architecture that uses OODBMS as the main persistent storage facility and that uses a coherent object based model (we can also, without loss of generality, restrict our attention to the OA subsets of mixed, non strictly object based, architectures). Such architectures need indeed very fine and detailed analysis and the use of dedicated (and formalized) approaches and methodologies. But the power of the object approach is, sometimes, weakened by the big effort to describe the relations between the objects, the objects states, static and dynamic behavior and so on. We can, for example, cite the scalability problem to face in large scale distributed (CORBA) object architectures and the problem of transitive persistency closure operation for (distributed) database objects. Could we relax, in some sense, the ”fully” object based approach using some other concept that makes easiest the analysis and the development of the OAs? The ”functional” approach, where the accent is mainly on the functions and their properties rather than on objects an their relations, helped us answering positively to the above question. 1for a complete reference please see [7], [8], [14], [12], [9] We would like not to debate on the OBJECTs vs FUNCTIONs approaches, but to use useful concepts of the functional approach in the analysis and development of distributed architectures: a functional ”shift” for object oriented programming, merging, whenever useful, functional and object oriented paradigms (see also [3], [4] and [13]). The aim of this paper, in the above described scenario, is thus to show an effort in the direction of partially fills a gap between functional and object oriented paradigms and to clarify some key points in distributed object based architectures. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.ktsi.com/carlos/papers/99/01820068.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
