Research On The Distributed Component Repository System Based On Peer-to-Peer Network

As one of practical approaches of software reuse, Component Based Software Development (CBSD) has become an efficient and feasible solution to solve software crisis. It improves software development efficiency and software quality remarkably. In CBSD, Component repository plays an important role. It is the rather crucial infrastructure of CBSD and serves as the foundation for CBSD. Therefore, as one of rather significant and meaning research fields, the research and development of component repository has received more and more attention from the software academia and industry.Nowadays, the research and development of the traditional C/S-based component repositories is still the focus of the software academia and industry. However, with software reuse and CBSD developing, such C/S-based component repositories fail to meet the needs of software development. On one hand, as the component repositories developing and the clients mounting up, the number of components will increase rapidly. However, the limiting storage capacity of central servers is unable to store such great amount of components. On the other hand, when the central servers always operate in the state of overload, they tend to suffer from the bottleneck of efficiency of component retrieval.As to the problems of the traditional C/S-based component repositories, the P2P network technology provides a good' solution. Considering the favorable technology characteristic and potential advantages of P2P network technology, we integrate P2P network technology into the research of component repositories. With referring to the researching fruits in the field of P2P-based file sharing systems, we propose a new P2P-based Distributed Component Repository, coined as P2P-DCR, which is constructed by organizing all the component-souring peers using P2P network technology. Furthermore, we have conducted an extensive study on some challenging technique problems for this new-stype component repository. The thesis has conducted the following researches and has achived the following contributions:1. We have systematically studied the network infrastracture and system framework of P2P-DCR.First, with the research fruits achived in the filed of P2P-based file sharing, we have proposed a superpeer-based network infrastrature to organize all the component-souring peers into a largely distributed component repository. Second, we have discussed detailedly the system framework of P2P-DCR which including component search engine, component indexing summary and storage structure; Finally, we have demonstrated detailedly the system evolution of P2P-DCR.2. We have systematically studied the flooding-based component search scheme in P2P-DCR.First, based on the network infrastrasture of P2P-DCR, we have discussed the basic flooding-based component search routing mechanism. Second, with the comprehensive analysis on the limitation of the basic flooding-based component search routing mechanism, we have proposed a new improved flooding-based routing mechamism which adapts a probabilistical weight-based message forwarding strategy.3. We have systematical studied the problem that how to integrate DHT-based component searching technique into the P2P-DCR.As to the shortcoming of the original flooding-based component search scheme in searching for rare components, we have proposed to extent the functionality of P2P-DCR to support the effective hybrid component search scheme. In this way, the extended P2P-DCR not only inherits the original flooding-based component search scheme but also possesses DHT-based structured component search scheme.4. We have systematically studied the mechanism and strategy of access control of component retrieval in P2P-DCR and proposed a trust-based component retrieval access control framework.Based on the analysis of the characteristics of access control in P2P-based component retrieval, we propose a trust-based component retrieval access control framework which is achived by expanding the traditional access control model. This framework integrates trust and recommendation model and access control model into P2P-based component repository, with the purpose of providing flavorable services for clients. Furthermore, the framework takes the decentralization of P2P-DCR into account.In a word, this thesis has proposed a P2P-based component repository, coined as P2P-DCR, which distinguishes from the traditional C/S-based repositories. This thesis also has systematically studied the design, key techniques and experimental results of P2P-DCR. All these contributions are achieved through a comprehensive study on the related theories, existing technologies and experimental results. Moreover, the experimental results have verified such a P2P-based component repository system can realize the search and sharing of components in a large distributed environment, and efficiently utilize the system's resource as well.