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Browsing by Author "Eberhard, John"

Now showing 1 - 2 of 2
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    Efficient Object Caching for Distributed Java RMI Applications
    (2001-11-20) Eberhard, John; Tripathi, Anand
    Java-based distributed applications generally use RMI(Remote Method Invocation)for accessing remote objects. When used in a wide-area environment, the performance of such applications can be poor because of the high latency of RMI. This latency can be reduced by caching objects at the client node. However, the use of caching introduces other issues, including the expense of caching the object as well as the expense of managing the consistency of the object. This paper presents a middleware for object caching in Java RMI-based distributed applications. The mechanisms used by the middleware are fully compatible with Java RMI and are transparent to the clients. Using this middleware, the system designer can select the caching strategy and consistency protocol most appropriate for theaplication. The paper illustrates the benefits of using these mechanisms to improve the performance of RMI applications.
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    Semantics Based Commutativity Analysis of Object Methods
    (2005-03-04) Eberhard, John; Tripathi, Anand
    Traditional analysis and usage of operation commutativity relies on pairwise commutativity relationships. In contrast, this paper presents method group commutativity, which specifies the conditions under which operations in a method group will commute. Method group commutativity can be practically applied to efficiently support distributed object caching and concurrency control. A formal definition of commutativity, in terms of Hoare logic expressions, guides the development of a methodology to create a method commutativity specification from an object's semantic specification. This methodology uses the PVS theorem prover for analysis and validation of commutativity properties. The use of formal methods, together with suitable tools, provides a more complete understanding of method commutativity relationships as compared to existing approaches. Our approach also provides a unified representation of both forward and backward commutativity properties. The methodology is also expanded to express weakened semantics in the method commutativity specification to enable greater commutativity.