Aspect] is a simple and practical aspect-oriented extension to Java With just a few new constructs, AspectJ provides support for modular implementation of a range of crosscutting concerns. In AspectJ's dynamic join point model, join points are well-defined points in the execution of the program; pointcuts are collections of join points; advice are special method-like constructs that can be attached to pointcuts; and aspects are modular units of crosscutting implementation, comprising pointcuts, advice, and ordinary Java member declarations. AspectJ code is compiled into standard Java bytecode. Simple extensions to existing Java development environments make it possible to browse the crosscutting structure of aspects in the same kind of way as one browses the inheritance structure of classes. Several examples show that AspectJ is powerful, and that programs written using it are easy to understand.

An overview of AspectJ

The authors evaluated the reliability and validity of a set of 7 behavioral decision-making tasks, measuring different aspects of the decision-making process The tasks were administered to individuals from diverse populations Participants showed relatively consistent performance within and across the 7 tasks, which were then aggregated into an Adult Decision-Making Competence (A-DMC) index that showed good reliability The validity of the 7 tasks and of overall A-DMC emerges in significant relationships with measures of socioeconomic status, cognitive ability, and decision-making styles Participants who performed better on the A-DMC were less likely to report negative life events indicative of poor decision making, as measured by the Decision Outcomes Inventory Significant predictive validity remains when controlling for demographic measures, measures of cognitive ability, and constructive decision-making styles Thus, A-DMC appears to be a distinct construct relevant to adults' real-world decisions

Individual differences in adult decision-making competence.

We introduce the Berlin Numeracy Test, a new psychometrically sound instrument that quickly assesses statistical numeracy and risk literacy. We present 21 studies (n=5336) showing robust psychometric discriminability across 15 countries (e.g., Germany, Pakistan, Japan, USA) and diverse samples (e.g., medical professionals, general populations, Mechanical Turk web panels). Analyses demonstrate desirable patterns of convergent validity (e.g., numeracy, general cognitive abilities), discriminant validity (e.g., personality, motivation), and criterion validity (e.g., numerical and nonnumerical questions about risk). The Berlin Numeracy Test was found to be the strongest predictor of comprehension of everyday risks (e.g., evaluating claims about products and treatments; interpreting forecasts), doubling the predictive power of other numeracy instruments and accounting for unique variance beyond other cognitive tests (e.g., cognitive reflection, working memory, intelligence). The Berlin Numeracy Test typically takes about three minutes to complete and is available in multiple languages and formats, including a computer adaptive test that automatically scores and reports data to researchers (www.riskliteracy.org). The online forum also provides interactive content for public outreach and education, and offers a recommendation system for test format selection. Discussion centers on construct validity of numeracy for risk literacy, underlying cognitive mechanisms, and applications in adaptive decision support.

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Measuring risk literacy: The Berlin numeracy test

Inevitably, reading is one of the requirements to be undergone. To improve the performance and quality, someone needs to have something new every day. It will suggest you to have more inspirations, then. However, the needs of inspirations will make you searching for some sources. Even from the other people experience, internet, and many books. Books and internet are the recommended media to help you improving your quality and performance.

Feature-Oriented Software Product Lines

A number of effective error detection tools have been built in recent years to check if a program conforms to certain design rules. An important class of design rules deals with sequences of events asso-ciated with a set of related objects. This paper presents a language called PQL (Program Query Language) that allows programmers to express such questions easily in an application-specific context. A query looks like a code excerpt corresponding to the shortest amount of code that would violate a design rule. Details of the tar-get application's precise implementation are abstracted away. The programmer may also specify actions to perform when a match is found, such as recording relevant information or even correcting an erroneous execution on the fly.We have developed both static and dynamic techniques to find solutions to PQL queries. Our static analyzer finds all potential matches conservatively using a context-sensitive, flow-insensitive, inclusion-based pointer alias analysis. Static results are also use-ful in reducing the number of instrumentation points for dynamic analysis. Our dynamic analyzer instruments the source program to catch all violations precisely as the program runs and to optionally perform user-specified actions.We have implemented the techniques described in this paper and found 206 errors in 6 large real-world open-source Java applica-tions containing a total of nearly 60,000 classes. These errors are important security flaws, resource leaks, and violations of consis-tency invariants. The combination of static and dynamic analysis proves effective at addressing a wide range of debugging and pro-gram comprehension queries. We have found that dynamic analysis is especially suitable for preventing errors such as security vulner-abilities at runtime.

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Finding application errors and security flaws using PQL: a program query language

An aspect observes the execution of a base program; when certain actions occur, the aspect runs some extra code of its own. In the AspectJ language, the observations that an aspect can make are confined to the current action: it is not possible to directly observe the history of a computation.Recently, there have been several interesting proposals for new history-based language features, most notably by Douence et al. and by Walker and Viggers. In this paper, we present a new history-based language feature called tracematches that enables the programmer to trigger the execution of extra code by specifying a regular pattern of events in a computation trace. We have fully designed and implemented tracematches as a seamless extension of AspectJ.A key innovation in our tracematch approach is the introduction of free variables in the matching patterns. This enhancement enables a whole new class of applications in which events can be matched not only by the event kind, but also by the values associated with the free variables. We provide several examples of applications enabled by this feature.After introducing and motivating the idea of tracematches via examples, we present a detailed semantics of our language design, and we derive an implementation from that semantics. The implementation has been realised as an extension of the abc compiler for AspectJ.

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Adding trace matching with free variables to AspectJ

Research in the design of aspect-oriented programming languages requires a workbench that facilitates easy experimentation with new language features and implementation techniques In particular, new features for AspectJ have been proposed that require extensions in many dimensions: syntax, type checking and code generation, as well as data flow and control flow analysesThe AspectBench Compiler (abc) is an implementation of such a workbench The base version of abc implements the full AspectJ language Its frontend is built, using the Polyglot framework, as a modular extension of the Java language The use of Polyglot gives flexibility of syntax and type checking The backend is built using the Soot framework, to give modular code generation and analysesIn this paper, we outline the design of abc, focusing mostly on how the design supports extensibility We then provide a general overview of how to use abc to implement an extension Finally, we illustrate the extension mechanisms of abc through a number of small, but non-trivial, examples abc is freely available under the GNU LGPL

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abc: an extensible AspectJ compiler

AspectJ, an aspect-oriented extension of Java, is becoming increasingly popular. However, not much work has been directed at optimising compilers for AspectJ. Optimising AOP languages provides many new and interesting challenges for compiler writers, and this paper identifies and addresses three such challenges.First, compiling around advice efficiently is particularly challenging. We provide a new code generation strategy for around advice, which (unlike previous implementations) both avoids the use of excessive inlining and the use of closures. We show it leads to more compact code, and can also improve run-time performance. Second, woven code sometimes includes run-time tests to determine whether advice should execute. One important case is the cflow pointcut which uses information about the dynamic calling context. Previous techniques for cflow were very costly in terms of both time and space. We present new techniques to minimise or eliminate the overhead of cflow using both intra- and inter-procedural analyses. Third, we have addressed the general problem of how to structure an optimising compiler so that traditional analyses can be easily adapted to the AOP setting.We have implemented all of the techniques in this paper in abc, our AspectBench Compiler for AspectJ, and we demonstrate significant speedups with empirical results. Some of our techniques have already been integrated into the production AspectJ compiler, ajc 1.2.1.

Optimising aspectJ

Aspects are a novel programming language feature, to express concerns in program design that crosscut traditional abstraction boundaries. The focus of this paper are dynamic aspects. Such aspects are specified as pointcut designators (patterns in the call stack), coupled with advice (code whose execution is triggered by the given pattern). We propose a more primitive syntax for pointcut designators, based on regular expressions. This primitive syntax facilitates a new static analysis that in turn enables a more efficient implementation of aspects.

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Static analysis of aspects

Size-change termination (SCT) automatically identifies termination of first-order functional programs. The SCT principle: a program terminates if every infinite control flow sequence would cause an infinite descent in a well-founded data value (POPL 2001).

More recent work (RTA 2004) developed a termination analysis of the pure untyped λ-calculus using a similar approach, but an entirely different notion of size was needed to compare higher-order values. Again this is a powerful analysis, even proving termination of certain λ-expressions containing the fixpoint combinator Y. However the language analysed is tiny, not even containing constants.

These techniques are unified and extended significantly, to yield a termination analyser for higher-order, call-by-value programs as in ML’s purely functional core or similar functional languages. Our analyser has been proven correct, and implemented for a substantial subset of OCaml.

Damien Sereni

Papers

Adding trace matching with free variables to AspectJ

abc: an extensible AspectJ compiler

Optimising aspectJ

Static analysis of aspects

Termination analysis of higher-order functional programs