Aspect-oriented Research Articles

A MATLAB subset to C compiler targeting embedded systems

Summary This paper describes MATISSE, a compiler able to translate a MATLAB subset to C targeting embedded systems. MATISSE uses LARA, an aspect-oriented programming language, to specify additional information and transformations to the input MATLAB code, for example, insertion of code for initialization of variables, and specification of types and shapes of variables. The compiler is being developed bearing in mind flexibility, multitarget and multitoolchain support, allowing for the generation of several implementations in C from the same reference code in MATLAB. In this paper, we also present a number of techniques being employed in MATLAB to C compilation, such as element-wise mapping operations, matrix views, weak types, and intrinsics. We validate these techniques using MATISSE and a set of representative benchmarks. More specifically, we evaluate the compiler with a set of 31 benchmarks using an embedded system board and a desktop computer. The results show speedups up to 1.8× by employing information provided by LARA aspects, when compared with C code generated without additional user information. When compared with the execution time of the original code running on MATLAB, the execution time of the generated C code achieved a geometric mean speedup of 13×.

Towards a comprehensive extension of abstract state machines for aspect-oriented specification

With the paradigm of aspect-orientation, a developer is able to separate the code of so-called cross-cutting concerns from the rest of the program's logic. This possibility is useful for formal specifications, too. For example, security aspects can be separated from the rest of the specification. Those aspect-oriented specifications often can be more easily reused than extensions that are implemented directly into an existing specification. Another use case is the extension of a specification with new functionality or features. Although this would be possible with refinement too, with aspect-orientation it is not necessary to augment the original specification with “extension points” that can be used for refinement.This paper describes the implementation of the aspect-oriented approach in Abstract State Machines. We introduce an aspect language with its syntax and formal semantics. It allows for specifying pointcuts where an original specification is augmented according to an aspect specification. Besides the general overview of this language extension, some ASM specific features of the realization are depicted in detail. The applicability of aspect-oriented specification in the context of ASM is demonstrated by means of examples, e.g. implementing a fading aspect into the light control system specification of a former ASM case study. Finally, the paper gives a brief overview about the developed tool that supports the writing of aspect-oriented ASMs.

Systems Engineering for Industrial Cyber–Physical Systems Using Aspects

One of the biggest challenges in cyber-physical system (CPS) design is their intrinsic complexity, heterogeneity, and multidisciplinary nature. Emerging distributed CPSs integrate a wide range of heterogeneous aspects such as physical dynamics, control, machine learning, and error handling. Furthermore, system components are often distributed over multiple physical locations, hardware platforms, and communication networks. While model-based design (MBD) has tremendously improved the design process, CPS design remains a difficult task. Models are meant to improve understanding of a system, yet this quality is often lost when models become too complicated. In this paper, we show how to use aspect-oriented (AO) modeling techniques in MBD as a systematic way to segregate domains of expertise and cross-cutting concerns within the model. We demonstrate these concepts on actor-oriented models of an industrial robotic swarm application and illustrate the use of AO modeling techniques to manage the complexity. We also show how to use AO modeling for design-space exploration.

Integration of aspect-oriented approach means in object-oriented programming language

The problem of complexity of developing and supporting the software cross-cutting concern and its solution using the aspect-oriented approach is examined. The complexity of aspect-oriented programming application in object-oriented programming languages is described. The problem of dependency of the declaration syntax of aspects and the method of their integration is investigated. The architecture that will provide the independence of the syntax of declaration and introduction of aspects in object-oriented programs is proposed. For separation, an urban design pattern that unites declaration of the aspect and its integration method is used. The system displays the classical entities of AOP in the object structure, which facilitates syntax mastering. Three methods for declaring aspects are developed, namely declaration using inheritance from a base class, template class generalization and flexible aspect creation at run time. For integration at compile time, a special integration module and the Roslyn compiler modification, which ensures implementation of the aspect configuration system and introduces advice invocation points in a code are developed. For integration at run time without using the dependency injection container, helper methods for creating proxy classes are designed. Also, modules for popular dependency injection containers, which allow integration by means of these containers are developed. Testing of the developed system, which showed a significant reduction in the size of a source code is carried out. The most pronounced reduction was in large enterprise-level systems. When using introduction at compile time, performance drop of programs is not observed. When using integration at run time, performance losses do not exceed those when using a similar proxy class.

AspectJ code analysis and verification with GASR

Aspect-oriented programming languages extend existing languages with new features for supporting modularization of crosscutting concerns. These features however make existing source code analysis tools unable to reason over this code. Consequently, all code analysis efforts of aspect-oriented code that we are aware of have either built limited analysis tools or were performed manually. Given the significant complexity of building them or manual analysis, a lot of duplication of effort could have been avoided by using a general-purpose tool. To address this, in this paper we present Gasr: a source code analysis tool that reasons over AspectJ source code, which may contain metadata in the form of annotations. GASR provides multiple kinds of analyses that are general enough such that they are reusable, tailorable and can reason over annotations. We demonstrate the use of GASR in two ways: we first automate the recognition of previously identified aspectual source code assumptions. Second, we turn implicit assumptions into explicit assumptions through annotations and automate their verification. In both uses GASR performs detection and verification of aspect assumptions on two well-known case studies that were manually investigated in earlier work. GASR finds already known aspect assumptions and adds instances that had been previously overlooked.

Using mutation to design tests for aspect-oriented models

Context: Testing for properties such as robustness or security is complicated because their concerns are often repeated in many locations and muddled with the normal code. Such “cross-cutting concerns” include things like interrupt events, exception handling, and security protocols. Aspect-oriented (AO) modeling allows developers to model the cross-cutting behavior independently of the normal behavior, thus supporting model-based testing of cross-cutting concerns. However, mutation operators defined for AO programs (source code) are usually not applicable to AO models (AOMs) and operators defined for models do not target the AO features.Objective: We present a method to design abstract tests at the aspect-oriented model level. We define mutation operators for aspect-oriented models and evaluate the generated mutants for an example system.Method: AOMs are mutated with novel operators that specifically target the AO modeling features. Test traces killing these mutant models are then generated. The generated and selected traces are abstract tests that can be transformed to concrete black-box tests and run on the implementation level, to evaluate the behavior of the woven cross-cutting concerns (combined aspect and base models).Results: This paper is a significant extension of our paper at Mutation 2015. We present a complete fault model, additional mutation operators, and a thorough analysis of the mutants generated for an example system.Conclusions: The analysis shows that some mutants are stillborn (syntactically illegal) but none is equivalent (exhibiting the same behavior as the original model). Additionally, our AOM-specific mutation operators can be combined with pre-existing operators to mutate code or models without any overlap.

Aspect Oriented Re-engineering of Legacy Software Using Cross-Cutting Concern Characterization and Significant Code Smells Detection

Although object-oriented programming (OOP) methodologies immensely promote reusable and well-factored decomposition of complex source code, legacy software systems often show symptoms of deteriorating design over time due to lack of maintenance. Software systems may have different business and application contexts, but most of these systems require similar maintenance mechanism of understanding, analysis and transformation. As a consequence, intensive re-engineering efforts based on the model driven approach can be effective ensuring that best practices are followed during maintenance and eventually reducing the development cost. In this paper, we suggest detailed framework of re-engineering which includes: (i) rigorous and automated source code analysis technique for identification, characterization and prioritization of most prominent and threatening design flaws in legacy software, (ii) migration of existing the code to aspect-oriented programming (AOP) code by exploiting current state of art for aspect mining mechanism and incorporating behavioral knowledge of cross-cutting concerns. To exemplify how the approach works a case study has been conducted to experimentally validate the idea and analyze the effect of process on specific software quality spectrum. An explicit analysis of prevalent work on the subject and their critical reviews are also presented to further enhance the recognition of proposed re-engineering framework.

Category-Theoretic Approach to Software Systems Design

Category theory is applied to the problem of representing heterogeneous software engineering technologies in a unified form suitable for their integration and coordination within the common software systems engineering cycle. Special attention is paid to modern technologies such as model-driven engineering and aspect-oriented programming. Universal category-theoretic semantic models of these technologies are constructed. A novel method of separation of concerns by explicating the aspectual structure of formal models of programs is proposed. We construct and analyze formal technologies (architecture schools) for designing technologies that comprise a mathematical basis for model-driven engineering.

Hardening an L4 Microkernel Against Soft Errors by Aspect-Oriented Programming and Whole-Program Analysis

Transient hardware faults in computer systems have become widespread as shrinking structures and low supply voltages reduce the amount of energy needed to trigger a fault. This paper describes the latest improvements of a software-based fault-tolerance mechanism called Generic Object Protection (GOP). It is based on Aspect-Orientied Programming in AspectC++ and has been used in a case study to harden the L4/Fiasco.OC microkernel. As a result, the improved GOP avoids 60% of kernel failures at an acceptable overhead of 19% code size and less than 1% runtime. The GOP improvements use static whole-program analysis and have been implemented in a prototypical manner. As an outlook, the paper presents envisioned language extensions providing whole-program control-flow and data-flow analyses in future AspectC++ versions.

Avoiding code pitfalls in Aspect-Oriented Programming

Aspect-Oriented Programming (AOP) is a maturing technique that requires a good comprehension of which types of mistakes programmers make during the development of applications. Unfortunately, the lack of such knowledge seems to represent one of the reasons for the cautious adoption of AOP in real software development projects. This paper reports on the results of a series of experiments whose main goal is to analyze and catalogue code pitfalls that are likely to lead programmers to make mistakes in AOP refactoring. Each experiment consists of a task that requires the aspectization of a crosscutting concern in one object-oriented application. Eight rounds of the experiment provided us with data of 98 AOP implementations from four crosscutting concerns in four different applications. Each participant of the experiment produced one implementation. Based on the analysis of these implementations, we (i) document six categories of recurring mistakes made by programmers, (ii) correlate these mistakes with the programmer expertise in object-oriented programming, years of software development, and pair programming, and (iii) derive a catalogue of code pitfalls which are likely to lead programmers to make the documented mistakes. We apply significance tests in order to statistically evaluate our results. We also present a prototype tool to warn programmers of the code pitfalls during refactoring activities.

Applying Separation of Concern for Developing Softwares Using Aspect Oriented Programming Concepts

Aspects provide a means of separating cross-cutting concerns from our core implementation code into separate modules. Cross-cutting concerns are pieces of functionality that are used across multiple parts of a system. They cut across, as opposed to standing alone. For example if every method of our program requires logging information for identification then a logging aspect can be applied to methods external to the method implementation without using logging information with the methods internally. It's a powerful technique to help employ the principle of separation of concerns within code. Aspect Oriented Programming (AOP) is a methodology that provides separation of crosscutting concerns by introducing a new unit of modularization—an aspect. Each aspect focuses on a specific crosscutting functionality.

On interplay between separation of concerns and genericity principles: Beyond code weaving

Ideally, we would separate concerns by designing a program so that each concern is contained in a module. Unfortunately, we often have to deal with concerns that cannot be modularized, but instead cross-cut modules of our primary decomposition. Some of the cross-cutting concerns can be separated using compositional techniques such as Aspect-Oriented Programming (AOP) that weave code into modules at specified program points. Here, we focus on cross-cutting concerns that would not be easily separable with code weaving compositional techniques due to their frequent and complex interactions with the modules of primary decomposition. Separation of Concerns (SoC) and genericity are two important Software Engineering principles to better control software complexity during development, maintenance, and reuse. In this paper, we study the interplay between these two principles, showing that there is an overlapping area where the goals of SoC and genericity, as well as means to achieve these goals, are the same. We make a case that by integrating the principles of SoC and genericity we can achieve non-redundancy, and at the same time enhance the visibility of inseparable concerns, offering a weaker, but still useful form of SoC. We illustrate the points we make with examples of program representations built with the Adaptive Reuse Technique (ART) that supports both SoC and generic mechanisms.

A development process for the design, implementation and code generation of fault tolerant reconfigurable real time systems

The implementation of hard real-time systems is an extremely tedious task today due to safety and dynamic reconfiguration requirements. For that, whatever the taken precautions, the occurrence of faults in such systems is sometimes unavoidable. So, developers have to take into account the presence of faults since the design level. In this context, we notice the need of techniques ensuring the dependability of real-time distributed dynamically reconfigurable systems. We focus on fault-tolerance, that means avoiding service failures in the presence of faults. In this paper, we have defined a development process for modelling and generating fault tolerance code for real-time systems using aspect-oriented programming. First, we integrate fault tolerance elements since the modelling step of a system in order to take advantage of features of analysis, proof and verification possible at this stage using AADL and its annex error model annex. Second, we extend an aspect-oriented language and adapt it to comply with real-time requirements. Finally, we define a code generation process for both functional preoccupations and cross-cutting ones like fault tolerance and we propose an extension of an existent middleware. To validate our contribution, we use AADL and its annexes to design a landing gear system as an embedded distributed one.

Polymorphic bytecode instrumentation

SummaryBytecode instrumentation is a widely used technique to implement aspect weaving and dynamic analyses in virtual machines such as the Java virtual machine. Aspect weavers and other instrumentations are usually developed independently and combining them often requires significant engineering effort, if at all possible. In this article, we present polymorphic bytecode instrumentation(PBI), a simple but effective technique that allows dynamic dispatch amongst several, possibly independent instrumentations. PBI enables complete bytecode coverage, that is, any method with a bytecode representation can be instrumented. We illustrate further benefits of PBI with three case studies. First, we describe how PBI can be used to implement a comprehensive profiler of inter‐procedural and intra‐procedural control flow. Second, we provide an implementation of execution levels for AspectJ, which avoids infinite regression and unwanted interference between aspects. Third, we present a framework for adaptive dynamic analysis, where the analysis to be performed can be changed at runtime by the user. We assess the overhead introduced by PBI and provide thorough performance evaluations of PBI in all three case studies. We show that pure Java profilers like JP2 can, thanks to PBI, produce accurate execution profiles by covering all code, including the core Java libraries. We then demonstrate that PBI‐based execution levels are much faster than control flow pointcuts to avoid interference between aspects and that their efficient integration in a practical aspect language is possible. Finally, we report that PBI enables adaptive dynamic analysis tools that are more reactive to user inputs than existing tools that rely on dynamic aspect‐oriented programming with runtime weaving. These experiments position PBI as a widely applicable and practical approach for combining bytecode instrumentations. © 2015 The Authors. Software: Practice and Experience Published by John Wiley & Sons Ltd.

An approach for deploying and monitoring dynamic security policies

Security policies are enforced through the deployment of certain security functionalities within the applications. When the security policies dynamically change, the associated security functionalities currently deployed within the applications must be adapted at runtime in order to enforce the new security policies. INTER-TRUST is a framework for the specification, negotiation, deployment and dynamic adaptation of interoperable security policies, in the context of pervasive systems where devices are constantly exchanging critical information through the network. The dynamic adaptation of the security policies at runtime is addressed using Aspect-Oriented Programming (AOP) that allows enforcing security requirements by dynamically weaving security aspects into the applications. However, a mechanism to guarantee the correct adaptation of the functionality that enforces the changing security policies is needed. In this paper, we present an approach based on the combination of monitoring and detection techniques in order to maintain the correlation between the security policies and the associated functionality deployed using AOP, allowing the INTER-TRUST framework to automatically react when needed.

Implementing design patterns as parametric aspects using ParaAJ: The case of the singleton, observer, and decorator design patterns

Implementation of a design pattern can take many forms according to the programming language being used. Most of the literature presents design patterns in their conventional object-oriented implementations. Several other studies show the implementation in aspect-oriented languages such as AspectJ, EOS, and Caesar. In this work, we compare the implementation of three design patterns: singleton, observer, and decorator design patterns in these languages and also discuss the possibility of implementing them in ParaAJ: an extension to the AspectJ language that implements the idea of parametric aspects. We found that ParaAJ helps in making the implementation of the singleton and observer patterns reusable but it fails to help in the decorator case. The problem with the decorator pattern exists because of the current translation mechanism of ParaAJ׳s aspects to normal AspectJ׳s aspects. This opens the door for further work in ParaAJ to better support the idea of parametric aspects.

Testing of aspect-oriented programs: difficulties and lessons learned based on theoretical and practical experience

Since the first discussions of new challenges posed by aspect-oriented programming (AOP) to software testing, the real difficulties of testing aspect-oriented (AO) programs have not been properly analysed. Firstly, despite the customisation of traditional testing techniques to the AOP context, the literature lacks discussions on how hard it is to apply them to (even ordinary) AO programs based on practical experience. Secondly, and equally important, due to the cautious AOP adoption focused on concern refactoring, test reuse is another relevant issue that has been overlooked so far. This paper deals with these two issues. It discusses the difficulties of testing AO programs from three perspectives: (i) structural-based testing, (ii) fault-based testing and (iii) test set reuse across paradigms. Perspectives (i) and (ii) are addressed by means of a retrospective of research done by the authors’ group. We analyse the impact of using AOP mechanisms on the testability of programs in terms of the underlying test models, the derived test requirements and the coverage of such requirements. The discussion is based on our experience on developing and applying testing approaches and tools to AspectJ programs at both unit and integration levels. Perspective (iii), on the other hand, consists of recent exploratory studies that analyse the effort to adapt test sets for refactored systems and the quality of such test sets in terms of structural coverage. Building test models for AO programs imposes higher complexity when compared to the OO paradigm. Besides this, adapting test suites for OO programs to AO equivalent programs tends to require less effort than doing the other way around, and resulting suites achieve similar quality levels for small-sized aplications. The conclusion is that building test models for AO programs, as well as deriving and covering paradigm-specific test requirements, is not straightforward as it has been for procedural and object-oriented (OO) programs at some extent. Once you have test suites in conformance with programs implemented in both paradigms, the quality of such suited in termos of code coverage may vary depending on the size and characteristics of the applications under testing.

Flexible and Extensible Runtime Verification for Java (Extended Version)

Runtime verification validates the correctness of a program’s execution trace. Much work has been done on improving the expressiveness and efficiency of runtime verification. However, current approaches require static deployment of the verification logic and are often restricted to a limited set of events that can be captured and analyzed, hindering the adoption of runtime verification in production systems. A popular system for runtime verification in Java, JavaMOP (Monitor-Oriented Programming in Java), suffers from the aforementioned limitations due to its dependence on AspectJ, which supports neither dynamic weaving nor an extensible join-point model. In this article, we extend the JavaMOP framework with a dynamic deployment API and a new MOP specification translator, which targets the domain-specific aspect language DiSL instead of AspectJ; DiSL offers an open join-point model that allows for extensions. A case study on lambda expressions in Java8 demonstrates the extensibility of our approach. Moreover, in comparison with JavaMOP using load-time weaving, our implementation reduces runtime overhead by 32%, and heap memory usage by 13%, on average.

The Effect of Overlapping Area on Ping-Pong Handover in LTE Networks

Aspect Oriented Programming (AOP) is a technique used to enhance the separation of concern in software design and implementation. To implement AOP developers most commonly use AspectJ, an extension of the Java language. In order to represent the separation of concerns a new design technique is needed for modeling of aspects. Aspect Oriented Design language (ASDL) is a design notation could build on the existing design language UML. It is capable of supporting many aspects-oriented languages. This research aims to investigate where developers can use aspect-oriented programming in the software development process. This includes how to identify Aspects in the design stage, then how they can be applied in the implementation process in software development. This will lead to improve modularity and reusability of the software. The paper will be a position paper abut Aspect Oriented Software Design, also will investigate several case studies of the design and implementation of a software application that shows how we can identify the Aspect in the process.

IMPROVING THE DESIGN AND IMPLEMENTATION OF SOFTWARE SYSTEMS USES ASPECT ORIENTED PROGRAMMING

Aspect Oriented Programming (AOP) is a technique used to enhance the separation of concern in software design and implementation. To implement AOP developers most commonly use AspectJ, an extension of the Java language. In order to represent the separation of concerns a new design technique is needed for modeling of aspects. Aspect Oriented Design language (ASDL) is a design notation could build on the existing design language UML. It is capable of supporting many aspects-oriented languages. This research aims to investigate where developers can use aspect-oriented programming in the software development process. This includes how to identify Aspects in the design stage, then how they can be applied in the implementation process in software development. This will lead to improve modularity and reusability of the software. The paper will be a position paper abut Aspect Oriented Software Design, also will investigate several case studies of the design and implementation of a software application that shows how we can identify the Aspect in the process.