Research On Some Key Technologies Of Component-based Software Upgrade

As software is being used in a wide range of human being's work and life and consequently becoming more and more complicated, people put an ever-growing demand on the flexibility and scalability of software system. This demand has contributed to the increasing importance of software upgrade technologies. In addition, the loopholes of software and network security make the importance of software upgrade more obvious. Basically, two kinds of key technologies are needed in order to implement software upgrade: software distribution technologies and software updating technologies. This thesis deals with these two issues.Software distribution technologies are to solve the problem of delivering software upgrade packages or software loopholes patches to terminals through network in limited time. P2P technology has become one of key technologies for software upgrade due to its decentralization, scalability, robustness and load-balancing. We narrow our research down to Chord algorithm, based on which we propose an optimized algorithm called ChordLandMark. According to the results of our experiments, this new algorithm decreases the average number of hops and query latency.In the process of software updating, sometime it is expensive to stop the software system to be updated. On some occasions, it is even impossible to stop the system, such as telecommunication system, industrial controlling system, banking system or air traffic controlling system. So, dynamic updating is needed to upgrade software system. In this thesis, we concentrate on component-based dynamic updating due to the unique advantages of component technologies. Focusing on state transfer between components in dynamic updating, we propose an approach that can dynamically update objects and prevent the so-called modification spread without modifying JVM. On basis of the mechanism of JVM's class loading and reflection, we design an experimental system which implements state transfer.