Andrea Caracciolo

A Unified Approach to Architecture Conformance Checking

Software erosion can be controlled by periodically checking for consistency between the de facto architecture and its theoretical counterpart. Studies show that this process is often not automated and that developers still rely heavily on manual reviews, despite the availability of a large number of tools. This is partially due to the high cost involved in setting up and maintaining tool-specific and incompatible test specifications that replicate otherwise documented invariants. To reduce this cost, our approach consists in unifying the functionality provided by existing tools under the umbrella of a common business-readable DSL. By using a declarative language, we are able to write tool-agnostic rules that are simple enough to be understood by untrained stakeholders and, at the same time, can be interpreted as a rigorous specification for checking architecture conformance.

How Do Software Architects Specify and Validate Quality Requirements

Software architecture is the result of a design effort aimed at ensuring a certain set of quality attributes. As we show, quality requirements are commonly specified in practice but are rarely validated using automated techniques. In this paper we analyze and classify commonly specified quality requirements after interviewing professionals and running a survey. We report on tools used to validate those requirements and comment on the obstacles encountered by practitioners when performing such activity (e.g., insufficient tool-support; poor understanding of user’s needs). Finally we discuss opportunities for increasing the adoption of automated tools based on the information we collected during our study (e.g., using a business-readable notation for expressing quality requirements; increasing awareness by monitoring non-functional aspects of a system).

Pangea: A Workbench for Statically Analyzing Multi-language Software Corpora

Software corpora facilitate reproducibility of analyses, however, static analysis for an entire corpus still requires considerable effort, often duplicated unnecessarily by multiple users. Moreover, most corpora are designed for single languages increasing the effort for cross-language analysis. To address these aspects we propose Pangea, an infrastructure allowing fast development of static analyses on multi-language corpora. Pangea uses language-independent meta-models stored as object model snapshots that can be directly loaded into memory and queryed without any parsing overhead. To reduce the effort of performing static analyses, Pangea provides out-of-the box support for: creating and refining analyses in a dedicated environment, deploying an analysis on an entire corpus, using a runner that supports parallel execution, and exporting results in various formats. In this tool demonstration we introduce Pangea and provide several usage scenarios that illustrate how it reduces the cost of analysis.

Polymorphism in the spotlight: studying its prevalence in Java and Smalltalk

Subtype polymorphism is a cornerstone of object-oriented programming. By hiding variability in behavior behind a uniform interface, polymorphism decouples clients from providers and thus enables genericity, modularity and extensibility. At the same time, however, it scatters the implementation of the behavior over multiple classes thus potentially hampering program comprehension. The extent to which polymorphism is used in real programs and the impact of polymorphism on program comprehension are not very well understood. We report on a preliminary study of the prevalence of polymorphism in several hundred open source software systems written in Smalltalk, one of the oldest object-oriented programming languages, and in Java, one of the most widespread ones. Although a large portion of the call sites in these systems are polymorphic, a majority have a small number of potential candidates. Smalltalk uses polymorphism to a much greater extent than Java. We discuss how these findings can be used as input for more detailed studies in program comprehension and for better developer support in the IDE.

Marea: A Semi-Automatic Decision Support System for Breaking Dependency Cycles

Dependency cycles are commonly recognized as one of the most critical quality anti-patterns. Cycles compromise the modularity of a system, prevent proper reuse and increase the cost of maintenance and testing. Many tools are capable of detecting and visualizing package cycles existing within software projects. Unfortunately, detecting cycles is only half of the work. Once detected, cycles need to be removed and this typically results in a complex process that is only partially supported by current tools. We propose a tool that offers an intelligent guidance mechanism to support developers in removing package cycles. Our tool, Marea, simulates different refactoring strategies and suggests the most cost-effective sequence of refactoring operations that will break the cycle. The optimal refactoring strategy is determined based on a custom profit function. Our approach has been validated on multiple projects and executes in linear time.

Evaluating an Architecture Conformance Monitoring Solution

Architectural rules are often defined but rarely tested. Current tools offer limited functionality and often require significant effort to be configured, automated and integrated within existing platforms. We propose a platform that is aimed at reducing the overall cost of setting up and maintaining an architectural conformance monitoring environment by decoupling the conceptual representation of a user-defined rule from its technical specification prescribed by the underlying analysis tools. The user is no longer expected to encode her constraints according to the syntax of the chosen tool, but can use a simple high-level DSL that is automatically compiled to an executable specification through custom adapters developed to support the interaction with existing off-the-shelf tools. In this paper we analyze three case studies to show how this approach can be successfully adopted to support truly diverse industrial projects. By discussing qualitative aspects of the approach, we investigate limitations and opportunities for improving general quality assessment solutions in general and DSL-based conformance tools in particular.

Dictō: A Unified DSL for Testing Architectural Rules

Software architecture consists of a set of design choices that can be partially expressed in form of rules that the implementation must conform to. Architectural rules are intended to ensure properties that fulfill fundamental non-functional requirements. Verifying architectural rules is often a non-trivial activity: available tools are often not very usable and support only a narrow subset of the rules that are commonly specified by practitioners. In this paper we present a new highly-readable declarative language for specifying architectural rules. With our approach, users can specify a wide variety of rules using a single uniform notation. Rules can get tested by third-party tools by conforming to pre-defined specification templates. Practitioners can take advantage of the capabilities of a growing number of testing tools without dealing with them directly.

A unified approach to automatic testing of architectural constraints

Architectural decisions are often encoded in the form of constraints and guidelines. Non-functional requirements can be ensured by checking the conformance of the implementation against this kind of invariant. Conformance checking is often a costly and error-prone process that involves the use of multiple tools, differing in effectiveness, complexity and scope of applicability. To reduce the overall effort entailed by this activity, we propose a novel approach that supports verification of human-readable declarative rules through the use of adapted off-the-shelf tools. Our approach consists of a rule specification DSL, called Dicto, and a tool coordination framework, called Probo. The approach has been implemented in a soon to be evaluated prototype.