Generic Model Refactorings

Many modeling languages share some common concepts and principles. For example, Java, MOF, and UML share some aspects of the concepts\ud of classes, methods, attributes, and inheritance. However, model\ud transformations such as refactorings specified for a given language\ud cannot be readily reused for another language because their related\ud metamodels may be structurally different. Our aim is to enable a\ud flexible reuse of model transformations across various metamodels.\ud Thus, in this paper, we present an approach allowing the specification\ud of generic model transformations, in particular refactorings, so\ud that they can be applied to different metamodels. Our approach relies\ud on two mechanisms: (1) an adaptation based mainly on the weaving\ud of aspects; (2) the notion of model typing, an extension of object\ud typing in the model-oriented context. We validated our approach by\ud performing some experiments that consisted of specifying three well\ud known refactorings (Encapsulate Field, Move Method, and Pull Up Method)\ud and applying each of them onto three different metamodels (Java,\ud MOF, and UML)

JEqualityGen: Generating Equality and Hashing Methods

Manually implementing equals (for object comparisons) and hashCode (for object hashing) methods in large software projects is tedious and error-prone. This is due to many special cases, such as field shadowing, comparison between different types, or cyclic object graphs. Here, we present JEqualityGen, a source code generator that automatically derives implementations of these methods. JEqualityGen proceeds in two states: it first uses source code reflection in MetaAspectJ to generate aspects that contain the method implementations, before it uses weaving on the bytecode level to insert these into the target application. JEqualityGen generates not only correct, but efficient source code that on a typical large-scale Java application exhibits a performance improvement of more than two orders of magnitude in the equality operations generated, compared to an existing system based on runtime reflection. JEqualityGen achieves this by generating runtime profiling code that collects data. This enables it to generate optimised method implementations in a second round

Towards an aspect weaving BPEL engine

This position paper proposes the use of dynamic aspects and the visitor design pattern to obtain a highly configurable and extensible BPEL engine. Using these two techniques, the core of this infrastructural software can be customised to meet new requirements and add features such as debugging, execution monitoring, or changing to another Web Service selection policy. Additionally, it can easily be extended to cope with customer-specific BPEL extensions. We propose the use of dynamic aspects not only on the engine itself but also on the workflow in order to tackle the problems of Web Service hot deployment and hot fixes to long running processes. In this way, composing aWeb Service "on-the-fly" means weaving its choreography interface into the workflow

Real world evaluation of aspect-oriented software development : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Computer Science at Massey University, Palmerston North, New Zealand

Software development has improved over the past decade with the rise in the popularity of the Object-Oriented (OO) development approach. However, software projects continue to grow in complexity and continue to have alarmingly low rates of success. Aspect-Oriented Programming (AOP) is touted to be one solution to this software development problem. It shows promise of reducing programming complexity, making software more flexible and more amenable to change. The central concept introduced by AOP is the aspect. An aspect is used to modularise crosscutting concerns in a similar fashion to the way classes modularise business concerns. A crosscutting concern cannot be modularised in approaches such as OO because the code to realise the concern must be spread throughout the module (e.g. a tracing concent is implemented by adding code to every method in a system). AOP also introduces join points, pointcuts, and advice which are used with aspects to capture crosscutting concerns so they can be localised in a modular unit. OO took approximately 20 years to become a mainstream development approach. AOP was only invented in 1997. This project considers whether AOP is ready for commercial adoption. This requires analysis of the AOP implementations available, tool support, design processes, testing tools, standards, and support infrastructure. Only when AOP is evaluated across all these criteria can it be established whether it is ready to be used in commercial projects. Moreover, if companies are to invest time and money into adopting AOP, they must be aware of the benefits and risks associated with its adoption. This project attempts to quantify the potential benefits in adopting AOP, as well as identifying areas of risk. SolNet Solutions Ltd, an Information Technology (IT) company in Wellington, New Zealand, is used in this study as a target environment for integration of aspects into a commercial development process. SolNet is in the business of delivering large scale enterprise Java applications. To assist in this process they have developed a Common Services Architecture (CSA) containing components that can be reused to reduce risk and cost to clients. However, the CSA is complicated and SolNet have identified aspects as a potential solution to decrease the complexity. Aspects were found to bring substantial improvement to the Service Layer of SolNet. applications, including substantial reductions in complexity and size. This reduces the cost and time of development, as well as the risk associated with the projects. Moreover, the CSA was used in a more consistent fashion making the system easier to understand and maintain, and several crosscutting concerns were modularised as part of a reusable aspect library which could eventually form part of their CSA. It was found that AOP is approaching commercial readiness. However, more work is needed on defining standards for aspect languages and modelling of design elements. The current solutions in this area are commercially viable, but would greatly benefit from a standardised approach. Aspect systems can be difficult to test and the effect of the weaving process on Java serialisation requires further investigation