CAA-DRIP: a framework for implementing Coordinated Atomic Actions

This paper presents an implementation framework, called CAA-DRIP, that has been defined to allow a straightforward implementation of dependable distributed applications designed using the coordinated atomic action (CAA) paradigm. CAAs provide a coherent set of concepts adapted to the design of fault tolerant distributed systems that includes: structured transactions, distribution, cooperation, competition, and forward and backward error recovery mechanisms triggered by exceptions. DRIP (dependable remote interacting processes) is an efficient Java implementation framework, which provides support for implementing "dependable multiparty interactions (DMI)" which includes a general exception handling mechanism. As DMI has a softer exception handling semantics with respect to CAA semantics, a CAA design can be implemented by DRIP. The aim of the CAA-DRIP framework is to provide a set of Java classes that allows programmers to implement only the semantics of CAAs with the same terminology and concepts at the design and implementation levels. The new framework simplifies the implementation phase and at the same time reduces the size of the final system since it requires fewer number of instances for creating a CAA at runtime. Details of these improvements as well as a precise description of the CAAs behaviour in terms of state charts, which is used as a reference model to define the CAA-DRIP framework, are presented in this paper