Fine-Grained Metrics of Cohesion Lack for Service Interfaces

Abstract

Abstract-A design issue that often appears in real-world services is that their interfaces are not cohesive, i.e., they consist of many and possibly unrelated operations. This issue may complicate the comprehension of the services functionalities and the maintenance of the applications that use them. Currently, the state of the art on cohesion metrics for service interfaces is limited. In particular, there exist coarse-grained metrics of cohesion lack, which consider that the operations of a service interface are related if the types of certain of their input/output data exactly match. The problem in this approach is that operations which operate on data characterized by similar, but not exactly matching, types are treated as being totaly unrelated. Consequently, the aforementioned metrics may overestimate the cohesion lack of service interfaces. In this paper, we undertake a more elaborate approach. Specifically, we propose two fine-grained metrics of cohesion lack, which are defined with respect to the structural similarity of the input/output data types of interface operations. The proposed metrics are formally defined and analytically assessed with respect to fundamental properties of software metrics. Moreover, the usefulness of the metrics in identifying cohesion problems is evaluated in real-world services.

Cohesion-Driven Decomposition of Service Interfaces without Access to Source Code

“…The third metric, called Lack of Domain-Level Cohesion (LoC dom ), considers relations between operations that are characterized by similar domain-level terms, which are extracted from the names of the operations. The proposed metrics extend our early ideas introduced in [6].…”

“…Cohesive software is easier to understand, test and maintain. In the case of Web service interfaces, the splitting should rely on a certain notion of cohesion that reflects the relatedness of the operations which are grouped in the same interface [2], [3], [4], [5], [6]. Technical challenge: Unfortunately, Alice cannot obtain her desideratum of splitting a service interface into a set of cohesive interfaces via the state of the art cohesion-driven refactoring methods [7], [8], [9], [10], [11], [12], [13], [14], [15].…”

“…The first efforts for measuring cohesion have been made in the work of Perepletchikov et al [5]. The first study that investigated the issue of cohesion in the case of real-world services is reported in Athanasopoulos & Zarras [6]. Finally, another interesting work that concerns the cohesion of services is presented in [30].…”

“…Concerning the state of the art metrics that we previously discussed and our prior work on cohesion metrics for service interfaces [6], the added value of this paper is the following:…”

The Role of Ontologies in Emergent Middleware: Supporting Interoperability in Complex Distributed Systems

“…In practice, networked systems do not advertise affordances but rather interfaces, as discussed below. Nevertheless, recent advances on learning techniques, combining solutions to the cohesion of system interfaces [18] and semantic knowledge inference [19], provide base ground that can be exploited to support the automated inference of affordances from interfaces, although this remains area for future work.…”