Overview and Evaluation of Constraint Validation Approaches in Java

Abstract

Integrity is a dependability attribute partially ensured through runtime validation of integrity constraints. A wide range of different constraint validation approaches exists-ranging from simple if conditions over explicit constraint validation methods and contract specifications to constraints as first class runtime entities of an application. However, increased support for explicitness and flexibility often comes at the price of increased performance costs. To address this issue, we contribute with an overview and evaluation of different constraint validation approaches for the Java programming language with respect to implementation, maintainability and performance. Our results show that the benefits of some of the more advanced approaches are certainly worth their costs by introducing a runtime overhead of only two to ten times the runtime of the fastest approach while other approaches introduce runtime overheads of more than 100, which might be simply too slow in certain applications.

Middleware Support for Adaptive Dependability

“…This concept allows detection and negotiation of consistency threats as a means to bound the potentially introduced inconsistency during degraded mode. According to our prototype implementation and additional evaluation studies [2,25], performance impairment due to explicit constraint consistency management is not an issue while the performance loss through synchronous replication is acceptable if (i) the read-to-write ratio is high, (ii) the number of replicated nodes within the system is small, and/or (iii) write performance is not a limiting factor. However, our approach increases availability at the expense of increased aggregate complexity during system reconciliation.…”

“…We conclude that only under extremely demanding performance requirements the performance impairment due to explicit constraint management may turn out to be a problem, see also [2,25] for further details. On the other hand, synchronous replication significantly reduces system performance for update operations while the performance of read operations is improved.…”

“…method in order to eliminate the validation overhead for reasonable overhead comparison. Details on this issue are available in [25]. To measure the behaviour in degraded mode when consistency threats occur, we called an empty method with an associated constraint 1000 times.…”

OCL-Based Runtime Monitoring of Applications with Protocol State Machines

“…Different approaches for checking information extracted from a running system for certain properties exist. [10] and [2] make a comparison between these approaches. According to [10] most constraint validation techniques for Java are based on the design-by-contract-principle introduced by the Eiffel programming language.…”

“…[10] and [2] make a comparison between these approaches. According to [10] most constraint validation techniques for Java are based on the design-by-contract-principle introduced by the Eiffel programming language. In contrast to our approach, the approaches compared to each other in [2] require a full access to the source code of the system under monitoring.…”