An Overview of Aspectj
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A Brief Introduction to Aspect-Oriented Programming
R R R A Brief Introduction to Aspect-Oriented Programming" R R Historical View Of Languages" R •# Procedural language" •# Functional language" •# Object-Oriented language" 1 R R Acknowledgements" R •# Zhenxiao Yang" •# Gregor Kiczales" •# Eclipse website for AspectJ (www.eclipse.org/aspectj) " R R Procedural Language" R •# Also termed imperative language" •# Describe" –#An explicit sequence of steps to follow to produce a result" •# Examples: Basic, Pascal, C, Fortran" 2 R R Functional Language" R •# Describe everything as a function (e.g., data, operations)" •# (+ 3 4); (add (prod 4 5) 3)" •# Examples" –# LISP, Scheme, ML, Haskell" R R Logical Language" R •# Also termed declarative language" •# Establish causal relationships between terms" –#Conclusion :- Conditions" –#Read as: If Conditions then Conclusion" •# Examples: Prolog, Parlog" 3 R R Object-Oriented Programming" R •# Describe " –#A set of user-defined objects " –#And communications among them to produce a (user-defined) result" •# Basic features" –#Encapsulation" –#Inheritance" –#Polymorphism " R R OOP (cont$d)" R •# Example languages" –#First OOP language: SIMULA-67 (1970)" –#Smalltalk, C++, Java" –#Many other:" •# Ada, Object Pascal, Objective C, DRAGOON, BETA, Emerald, POOL, Eiffel, Self, Oblog, ESP, POLKA, Loops, Perl, VB" •# Are OOP languages procedural? " 4 R R We Need More" R •# Major advantage of OOP" –# Modular structure" •# Potential problems with OOP" –# Issues distributed in different modules result in tangled code." –# Example: error logging, failure handling, performance -
Smart Execution of Distributed Application by Balancing Resources in Mobile Devices
ALMA MATER STUDIORUM - UNIVERSITÀ DI BOLOGNA SCUOLA DI INGEGNERIA E ARCHITETTURA DISI INGEGNERIA INFORMATICA TESI DI LAUREA in Reti di Calcolatori M Smart execution of distributed application by balancing resources in mobile devices and cloud-based avatars CANDIDATO: RELATORE: Giacomo Gezzi Chiar.mo Prof. Ing. Antonio Corradi CORRELATORE: Chiar.mo Prof. Cristian Borcea Anno Accademico 2014/2015 Sessione III 2 Abstract L’obiettivo del progetto di tesi svolto e` quello di realizzare un servizio di livello middleware dedicato ai dispositivi mobili che sia in grado di fornire il supporto per l’offloading di codice verso una infrastruttura cloud. In particolare il progetto si concentra sulla migrazione di codice verso macchine virtuali dedicate al singolo utente. Il sistema operativo delle VMs e` lo stesso utilizzato dal device mobile. Come i precedenti lavori sul computation offloading, il progetto di tesi deve garantire migliori per- formance in termini di tempo di esecuzione e utilizzo della batteria del dispositivo. In particolare l’obiettivo piu` ampio e` quello di adattare il principio di computation offloading a un contesto di sistemi distribuiti mobili, miglio- rando non solo le performance del singolo device, ma l’esecuzione stessa dell’applicazione distribuita. Questo viene fatto tramite una gestione di- namica delle decisioni di offloading basata, non solo, sullo stato del de- vice, ma anche sulla volonta` e/o sullo stato degli altri utenti appartenenti allo stesso gruppo. Per esempio, un primo utente potrebbe influenzare le decisioni degli altri membri del gruppo specificando una determinata richiesta, come alta qualita` delle informazioni, risposta rapida o basata su altre informazioni di alto livello. -
The Machine That Builds Itself: How the Strengths of Lisp Family
Khomtchouk et al. OPINION NOTE The Machine that Builds Itself: How the Strengths of Lisp Family Languages Facilitate Building Complex and Flexible Bioinformatic Models Bohdan B. Khomtchouk1*, Edmund Weitz2 and Claes Wahlestedt1 *Correspondence: [email protected] Abstract 1Center for Therapeutic Innovation and Department of We address the need for expanding the presence of the Lisp family of Psychiatry and Behavioral programming languages in bioinformatics and computational biology research. Sciences, University of Miami Languages of this family, like Common Lisp, Scheme, or Clojure, facilitate the Miller School of Medicine, 1120 NW 14th ST, Miami, FL, USA creation of powerful and flexible software models that are required for complex 33136 and rapidly evolving domains like biology. We will point out several important key Full list of author information is features that distinguish languages of the Lisp family from other programming available at the end of the article languages and we will explain how these features can aid researchers in becoming more productive and creating better code. We will also show how these features make these languages ideal tools for artificial intelligence and machine learning applications. We will specifically stress the advantages of domain-specific languages (DSL): languages which are specialized to a particular area and thus not only facilitate easier research problem formulation, but also aid in the establishment of standards and best programming practices as applied to the specific research field at hand. DSLs are particularly easy to build in Common Lisp, the most comprehensive Lisp dialect, which is commonly referred to as the “programmable programming language.” We are convinced that Lisp grants programmers unprecedented power to build increasingly sophisticated artificial intelligence systems that may ultimately transform machine learning and AI research in bioinformatics and computational biology. -
The Inheritance Anomaly Revisited
The Inheritance Anomaly Revisited Ryan J. Wisnesky August 2006 Contents Contents i Preface ii Introduction 1 1 The Inheritance Anomaly and Formal Framework 2 1.1 An Overview of the Inheritance Anomaly . 2 1.2 An Overview of the Framework . 4 2 History-based Guard Languages 7 2.1 History-based guard languages . 7 2.2 Two tweaks . 8 2.2.1 The first tweak: Behavior Preservation . 8 2.2.2 The second tweak: Patching the Proof . 10 2.3 Discussion . 13 2.4 Related Work and Future Directions . 13 2.5 Conclusion . 15 3 Intra-object Concurrency 16 3.1 Methods and Messages . 16 3.1.1 New synchronization constructs . 17 3.1.2 Synchronization, Methods, and Messages . 18 3.2 New Types . 19 3.2.1 Mutual Exclusion: TypesS ............................ 20 3.2.2 Mutual Exclusion and Containment: TypesS .................. 24 3.2.3 TypesT,S ...................................... 25 3.3 Conclusion and Related Work . 27 4 Specification Languages 28 5 Overall Conclusion, Future Directions, and a Note on Typing 29 6 Related Work 30 6.1 Core Papers . 30 i 6.2 Concurrent Formal Systems . 31 6.3 Anomaly Avoidance Mechanisms . 33 6.4 Anomaly Generalizations . 36 6.5 Anomaly Experiences . 36 6.6 Surveys . 37 6.7 Aspect-Oriented Programming . 37 6.8 Others............................................ 38 Bibliography 41 ii Introduction The Inheritance Anomaly has been a thorn in the side of the concurrent object-oriented language community for 15 years. Simply put, the anomaly is a failure of inheritance and concurrency to work well with each other, negating the usefulness of inheritance as a mechanism for code-reuse in a concurrent setting. -
Continuation Join Points
Continuation Join Points Yusuke Endoh, Hidehiko Masuhara, Akinori Yonezawa (University of Tokyo) 1 Background: Aspects are reusable in AspectJ (1) Example: A generic logging aspect can log user inputs in a CUI program by defining a pointcut Login Generic Logging id = readLine(); Aspect Main CUI Aspect cmd = readLine(); pointcut input(): call(readLine()) logging return value 2 Background: Aspects are reusable in AspectJ (2) Example: A generic logging aspect can also log environment variable by also defining a pointcut Q. Now, if we want to log environment variable (getEnv) …? Generic Logging Aspect A. Merely concretize an aspect additionally Env Aspect CUI Aspect pointcut input(): pointcut input(): Aspect reusability call(getEnv()) call(readLine()) 3 Problem: Aspects are not as reusable as expected Example: A generic logging aspect can NOT log inputs in a GUI program by defining a pointcut Login Generic Logging void onSubmit(id) Aspect { … } Main void onSubmit(cmd) GUI Aspect { … } pointcut Input(): call(onSubmit(Str)) logging arguments 4 Why can’t we reuse the aspect? Timing of advice execution depends on both advice modifiers and pointcuts Logging Aspect (inner) Generic Logging abstract pointcut: input(); Aspect after() returning(String s) : input() { Log.add(s); } unable to change to before 5 Workaround in AspectJ is awkward: overview Required changes for more reusable aspect: generic aspect (e.g., logging) two abstract pointcuts, two advice decls. and an auxiliary method concrete aspects two concrete pointcuts even if they are not needed 6 Workaround in AspectJ is awkward: how to define generic aspect Simple Logging Aspect 1. define two pointcuts abstract pointcut: inputAfter(); for before and after abstract pointcut: inputBefore(); after() returning(String s) : inputAfter() { log(s); } 2. -
Towards an Expressive and Scalable Framework for Expressing Join Point Models
Towards an Expressive and Scalable Framework for expressing Join Point Models Pascal Durr, Lodewijk Bergmans, Gurcan Gulesir, Istvan Nagy University of Twente {durr,bergmans,ggulesir,nagyist}@ewi.utwente.nl ABSTRACT a more fine-grained join point model is required. Moreover, Join point models are one of the key features in aspect- these models are mostly rooted in control flow and call graph oriented programming languages and tools. They provide information, but sometimes a pointcut expression based on software engineers means to pinpoint the exact locations in data flow or data dependence is more suitable. programs (join points) to weave in advices. Our experi- ence in modularizing concerns in a large embedded system This paper proposes an expressive and scalable fine-grained showed that existing join point models and their underlying framework to define join point models that incorporate both program representations are not expressive enough. This data and control flow analysis. One can subsequently specify prevents the selection of some join points of our interest. In a pointcut language which implements (part of) this join this paper, we motivate the need for more fine-grained join point model. Allowing different implementation strategies point models within more expressive source code represen- and language independence is the strength of this model. tations. We propose a new program representation called a program graph, over which more fine-grained join point The paper is structured as follows: First, we will motivate models can be defined. In addition, we present a simple lan- this research with two example concerns we encountered in guage to manipulate program graphs to perform source code our IDEALS[6] project with ASML[2]. -
Flowr: Aspect Oriented Programming for Information Flow Control in Ruby
FlowR: Aspect Oriented Programming for Information Flow Control in Ruby Thomas F. J.-M. Pasquier Jean Bacon Brian Shand University of Cambridge Public Health England fthomas.pasquier, [email protected] [email protected] Abstract Track, a taint-tracking system for Ruby, developed by the SafeWeb This paper reports on our experience with providing Information project [17]. Flow Control (IFC) as a library. Our aim was to support the use However, we came to realise certain limitations of the mech- of an unmodified Platform as a Service (PaaS) cloud infrastructure anisms we had deployed. For example, to enforce the required by IFC-aware web applications. We discuss how Aspect Oriented IFC policy, we manually inserted IFC checks at selected applica- Programming (AOP) overcomes the limitations of RubyTrack, our tion component boundaries. In practice, objects and classes are the first approach. Although use of AOP has been mentioned as a natural representation of application components within an object possibility in past IFC literature we believe this paper to be the oriented language and it seems natural to relate security concerns first illustration of how such an implementation can be attempted. with those objects. We should therefore associate the primitives and We discuss how we built FlowR (Information Flow Control for mechanisms to enforce IFC with selected objects. Furthermore, we Ruby), a library extending Ruby to provide IFC primitives using wish to be able to assign boundary checks on any class or object AOP via the Aquarium open source library. Previous attempts at without further development overhead. We also wish to be able providing IFC as a language extension required either modification to exploit the inheritance property to define rules that apply to of an interpreter or significant code rewriting. -
“An Introduction to Aspect Oriented Programming in E”
“An Introduction to Aspect Oriented Programming in e” David Robinson [email protected] Rel_1.0: 21-JUNE-2006 Copyright © David Robinson 2006, all rights reserved 1 This white paper is based on the forthcoming book “What's so wrong with patching anyway? A pragmatic guide to using aspects and e”. Please contact [email protected] for more information. Rel_1.0: 21-JUNE-2006 2 Copyright © David Robinson 2006, all rights reserved Preface ______________________________________ 4 About Verilab__________________________________ 7 1 Introduction _______________________________ 8 2 What are aspects - part I? _____________________ 10 3 Why do I need aspects? What’s wrong with cross cutting concerns? ___________________________________ 16 4 Surely OOP doesn’t have any problems? ___________ 19 5 Why does AOP help?_________________________ 28 6 Theory vs. real life - what else is AOP good for? ______ 34 7 What are aspects - part II?_____________________ 40 Bibliography _________________________________ 45 Index ______________________________________ 48 Rel_1.0: 21-JUNE-2006 Copyright © David Robinson 2006, all rights reserved 3 Preface “But when our hypothetical Blub programmer looks in the other direction, up the power continuum, he doesn't realize he's looking up. What he sees are merely weird languages. He probably considers them about equivalent in power to Blub, but with all this other hairy stuff thrown in as well. Blub is good enough for him, because he thinks in Blub” Paul Graham 1 This paper is taken from a forthcoming book about Aspect Oriented Programming. Not just the academic stuff that you’ll read about elsewhere, although that’s useful, but the more pragmatic side of it as well. -
The Inheritance Anomaly: Ten Years After
The inheritance anomaly: ten years after Giuseppe Milicia Vladimiro Sassone Chi Spaces Technologies ltd. University of Sussex, UK Cambridge, UK [email protected] [email protected] ABSTRACT Clearly we must make sure that no object is removed from an The term inheritance anomaly was coined in 1993 by Matsuoka empty buffer and that no object is inserted into a full buffer. In a and Yonezawa [15] to refer to the problems arising by the coexis- sequential setting, the burden of ensuring such constraints resides tence of inheritance and concurrency in concurrent object oriented with the buffer’s user. Indeed the buffer is created and used by languages (COOLs). The quirks arising by such combination have one thread only, which is responsible for the state of the object. been observed since the early eighties, when the first experimen- To facilitate usage, the buffer’s methods might return certain er- tal COOLs were designed [3]. In the nineties COOLs turned from ror codes in case of misuse. This approach is not feasible in a research topic to widely used tools in the everyday programming concurrent setting. The buffer will be used concurrently by mul- practice, see e.g. the Java [9] experience. This expository paper ex- tiple clients, leaving each of them no idea on the buffer’s current tends the survey presented in [15] to account for new and widely state. Although it is possible to envisage ad-hoc protocols among used COOLs, most notably Java and C] [19]. Specifically, we il- clients to keep track of the buffer’s state, such a solution is com- lustrate some innovative approaches to COOL design relying on plex and hardly feasible in practice. -
Source-Code Instrumentation and Quantification of Events Robert E
Source-Code Instrumentation and Quantification of Events Robert E. Filman Klaus Havelund RIACS Kestrel Technology NASA Ames Research Center, MS 269/2 NASA Ames Research Center, MS 269/2 Moffett Field, CA 94035 U.S.A. Moffett Field, CA 94035 U.S.A +1 650–604–1250 +1 650–604–3366 [email protected] [email protected] ABSTRACT particularly with respect to debugging and validating concurrent Aspect-Oriented Programming is making quantified programmatic systems. assertions over programs that otherwise are not annotated to 2. EVENTS receive these assertions. Varieties of AOP systems are Quantification implies matching a predicate about a program. characterized by which quantified assertions they allow, what they Such a predicate must be over some domain. In the permit in the actions of the assertions (including how the actions quantification/implicit invocation papers, we distinguished interact with the base code), and what mechanisms they use to between static and dynamic quantification. achieve the overall effect. Here, we argue that all quantification is over dynamic events, and describe our preliminary work in Static quantification worked over the structure of the program. developing a system that maps dynamic events to transformations That is, with static quantification, one could reference the over source code. We discuss possible applications of this system, programming language structures in a system. Examples of such particularly with respect to debugging concurrent systems. structures include reference to program variables, calls to subprograms, loops, and conditional tests. Categories and Subject Descriptors Many common AOP implementation techniques can be D.3.3 [Programming Languages]: Language Constructs and understood in terms of quantified program manipulation on the Features – aspects. -
Understanding AOP Through the Study of Interpreters
Understanding AOP through the Study of Interpreters Robert E. Filman Research Institute for Advanced Computer Science NASA Ames Research Center, MS 269-2 Moffett Field, CA 94035 rfi[email protected] ABSTRACT mapping is of interest (e.g., variables vs. functions). The I return to the question of what distinguishes AOP lan- pseudo-code includes only enough detail to convey the ideas guages by considering how the interpreters of AOP lan- I’m trying to express. guages differ from conventional interpreters. Key elements for static transformation are seen to be redefinition of the Of course, a real implementation would need implementa- set and lookup operators in the interpretation of the lan- tions of the helper functions. In general, the helper functions guage. This analysis also yields a definition of crosscutting on environments—lookup, set, and extend—can be manip- in terms of interlacing of interpreter actions. ulated to create a large variety of different language fea- tures. The most straightforward implementation makes an environment a set of symbol–value pairs (a map from sym- 1. INTRODUCTION bols to values) joined to a pointer to a parent environment. I return to the question of what distinguishes AOP lan- Lookup finds the pair of the appropriate symbol, (perhaps guages from others [12, 14]. chaining through the parent environments in its search), re- turning its value; set finds the pair and changes its value A good way of understanding a programming language is by field; and extend builds a new map with some initial val- studying its interpreter [17]. This motif has been recently ues whose parent is the environment being extended. -
Design Pattern Implementation in Java and Aspectj
Design Pattern Implementation in Java and AspectJ Jan Hannemann Gregor Kiczales University of British Columbia University of British Columbia 201-2366 Main Mall 201-2366 Main Mall Vancouver B.C. V6T 1Z4 Vancouver B.C. V6T 1Z4 jan [at] cs.ubc.ca gregor [at] cs.ubc.ca ABSTRACT successor in the chain. The event handling mechanism crosscuts the Handlers. AspectJ implementations of the GoF design patterns show modularity improvements in 17 of 23 cases. These improvements When the GoF patterns were first identified, the sample are manifested in terms of better code locality, reusability, implementations were geared to the current state of the art in composability, and (un)pluggability. object-oriented languages. Other work [19, 22] has shown that implementation language affects pattern implementation, so it seems The degree of improvement in implementation modularity varies, natural to explore the effect of aspect-oriented programming with the greatest improvement coming when the pattern solution techniques [11] on the implementation of the GoF patterns. structure involves crosscutting of some form, including one object As an initial experiment we chose to develop and compare Java playing multiple roles, many objects playing one role, or an object [27] and AspectJ [25] implementations of the 23 GoF patterns. playing roles in multiple pattern instances. AspectJ is a seamless aspect-oriented extension to Java, which means that programming in AspectJ is effectively programming in Categories and Subject Descriptors Java plus aspects. D.2.11 [Software Engineering]: Software Architectures – By focusing on the GoF patterns, we are keeping the purpose, patterns, information hiding, and languages; D.3.3 intent, and applicability of 23 well-known patterns, and only allowing [Programming Languages]: Language Constructs and Features – the solution structure and solution implementation to change.