DOCSLIB.ORG

(Postprint): Efficient Late Bind

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
(Postprint): Efficient Late Bind Dieses Dokument ist eine Zweitveröffentlichung (Postprint) / This is a self-archiving document (postprint): Lars Schütze, Jeronimo Castrillon Efficient Late Binding of Dynamic Function Compositions Erstveröffentlichung in / First published in: SLE 2019: 12th ACM SIGPLAN International Conference on Software Language Engineering, Athens, 2019. ACM Digital Library, S. 141 – 151. ISBN 978-1-4503-6981-7 DOI: https://doi.org/10.1145/3357766.3359543 Diese Version ist verfügbar / This version is available on: https://nbn-resolving.org/urn:nbn:de:bsz:14-qucosa2-731781 Final edited form was published in "SLE 2019: 12th ACM SIGPLAN International Conference on Software Language Engineering", Athens, 2019. S. 141 – 151. ISBN 978-1-4503-6981-7 https://doi.org/10.1145/3357766.3359543 Efficient Late Binding of Dynamic Function Compositions Lars Schütze Jeronimo Castrillon Chair for Compiler Construction Chair for Compiler Construction Technische Universität Dresden Technische Universität Dresden Dresden, Germany Dresden, Germany [email protected] [email protected] Abstract 1 Introduction Adaptive software becomes more and more important as Ubiquitous computing leads to new challenges where context- computing is increasingly context-dependent. Runtime adapt- dependent software is more and more important. Developing ability can be achieved by dynamically selecting and apply- such software requires approaches that focus on objects, their ing context-specific code. Role-oriented programming has context-dependent behavior and relations. Object-oriented been proposed as a paradigm to enable runtime adaptive soft- programming (OOP) is the de facto standard approach to ware by design. Roles change the objects’ behavior at run- those problems today. This is because of the comprehensi- time and thus allow adapting the software to a given context. bility of object-oriented models and code which enables an However, this increased variability and expressiveness has intuitive representation of aspects of the real world. That is a direct impact on performance and memory consumption. how classes, objects, functions and inheritance originated. We found a high overhead in the steady-state performance of For example, an aspect of the real world is that an object may executing compositions of adaptations. This paper presents appear in different roles at different times (i.e., contexts). To a new approach to use run-time information to construct a reflect the different roles of entities, design patterns have dispatch plan that can be executed efficiently by the JVM. been proposed to achieve separation of concerns [7, 15]. Be- The concept of late binding is extended to dynamic func- cause these approaches can only compose or decompose in a tion compositions. We evaluated the implementation with a single dimension by using delegation or inheritance, context- benchmark for role-oriented programming languages lever- dependent concerns are tangled with the application and aging context-dependent role semantics achieving a mean scattered over it. speedup of 2.79× over the regular implementation. With the advent of aspect-oriented programming (AOP) [33] and context-oriented programming (COP) [28] it was possi- CCS Concepts • Software and its engineering → Soft- ble to separate behavioral concerns in multiple dimensions. ware performance; Compilers; Context specific languages. However, the focus of these multi-dimensional separation of Keywords Role-Oriented Programming, Dispatch Optimiza- concerns (MDSOC) paradigms is on the cross-cutting nature tion, Virtual Machine of concerns and adaptation of classes. Role-oriented programming (ROP) has been proposed as ACM Reference Format: an extension to object-oriented programming to enable adap- Lars Schütze and Jeronimo Castrillon. 2019. Efficient Late Binding tive software by design [43, 47]. Classes represent the struc- of Dynamic Function Compositions. In Proceedings of the 12th ACM tural view of the program while context-dependent behavior SIGPLAN International Conference on Software Language Engineer- is encapsulated in separate entities called roles. To model ing (SLE ’19), October 20–22, 2019, Athens, Greece. ACM, New York, context-dependency compartments encapsulate roles and NY, USA, 11 pages. https://doi.org/10.1145/3357766.3359543 represent the context in which these roles can be active. Adaptation is achieved by attaching roles dynamically to ©2019 Copyright held by the owner/author(s). Publication rights licensed objects to superimpose their behavior. Object Teams [23, 24] to ACM. This is the author’s version of the work. It is posted here for your is one of the most mature role-oriented programming lan- personal use. Not for redistribution. The definitive Version of Record was guages. It allows adapting Java programs available in source published in SSLE ’19, October 20–22, 2019, Athens, Greece code or binary form dynamically at runtime. https://doi.org/10.1145/3357766.3359543 It is common practice to lower MDSOC mechanisms to object-oriented mechanisms, which results in a verbose de- scription that incurs high runtime overhead [3, 40]. The over- head is especially noticeable in the steady-state performance of dynamic role-oriented programming languages as the be- havior of every object may be potentially adapted [46]. We argue that the major cause for the overhead is that current 1 Provided by Sächsische Landesbibliothek - Staats- und Universitätsbibliothek Dresden Final edited form was published in "SLE 2019: 12th ACM SIGPLAN International Conference on Software Language Engineering", Athens, 2019. S. 141 – 151. ISBN 978-1-4503-6981-7 https://doi.org/10.1145/3357766.3359543 SLE ’19, October 20–22, 2019, Athens, Greece Lars Schütze and Jeronimo Castrillon translation approaches have not been able to properly close have code for multiple concerns. This collaboration-scoped the semantic gap between role-oriented mechanisms and usage cannot be directly represented but is scattered over object-oriented machine models preventing many possible the program. While design patterns improve the quality of optimisationz. software architectures, they cannot solve the problem of To close the semantic gap and reduce verbosity the execu- tangling and scattering of concerns satisfactorily. To solve tion environment must understand the enhanced execution the problem, different approaches for separation of concerns semantics. We address this problem by applying the concept have been proposed with varying degree of granularity rang- of late binding of virtually dispatched functions to function ing from adapting single objects or functions to classes and compositions using exact runtime type information. Func- components. tions superimposed by role functions are by default virtual, but may become static until superimposition is released re- Aspect-Oriented Programming AOP decomposes cross- sulting in no subsequent lookups. The runtime provides cutting concerns to encapsulate each concern separately. As- exact instructions to the execution environment about how pects encapsulate such concerns and provide expressions to to find and execute role functions by composing a directed define interceptors, class extensions (inter-type declarations) acyclic graph (DAG) of function calls. This not only allows and its own properties [12]. An aspect can alter the behav- optimizing role dispatch in the sense of Just-in-Time (JIT) ior of non-aspect parts of the program called base classes compilation by the execution environment but also improves by applying advices which define the additional behavior. the runtime and generated code in terms of lookup and reuse. Alternative behavior can be applied at join points in the We demonstrate our approach by extending the static com- base program including function calls and property access. piler, dynamic compiler and the runtime of Object Teams [23, Pointcuts provide predicates that quantify over the set of 24]. We used a typical synthetic benchmark already reported existing join points and choose the set of join points where in the literature to compare different language implementa- the execution of the advice is desired. Aspects are woven tions of the role-oriented concept [46]. The benchmark uses into the application using special compilers called weavers. many demanding role-oriented programming features such Join points where advice invocation code may be woven in as multiple active contexts, deep roles (i.e., roles play roles), are called join point shadows [27]. and exchanged function bodies that are not easily built with A compiler for the aspect-oriented language consists of object-oriented design patterns. Our evaluation features a a module for evaluating pointcuts and the aforementioned mean speedup of 2.79× over the original implementation weaver, beside the elements of a traditional compiler. After when callsites can be reused and a mean slowdown of 9.76× evaluating a pointcut, the join point shadows are forwarded if there is no possible reuse ever. to the weaver. But at weave-time it cannot be decided for all The paper introduces in Section 2 concepts similar to join point shadows whether pointcuts apply or not. Thus, roles that could also benefit from the approach and gives an for some join points advice invocation logic and guards are overview of how Object Teams implements roles. In Section 3 compiled into the application called residuals. late binding for function compositions of role functions is Since virtual machine does not understand aspect seman-
Load more

Recommended publications
  • 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.
    [Show full text]
  • Aspectmaps: a Scalable Visualization of Join Point Shadows
    AspectMaps: A Scalable Visualization of Join Point Shadows Johan Fabry ∗ Andy Kellens y Simon Denier PLEIAD Laboratory Software Languages Lab Stephane´ Ducasse Computer Science Department (DCC) Vrije Universiteit Brussel RMoD, INRIA Lille - Nord Europe University of Chile Belgium France http://pleiad.cl http://soft.vub.ac.be http://rmod.lille.inria.fr of join points. Second, the specification of the implicit invocations is made through a pointcut that selects at which join points the Abstract aspect executes. The behavior specification of the aspect is called the advice. An aspect may contain various pointcuts and advices, When using Aspect-Oriented Programming, it is sometimes diffi- where each advice is associated with one pointcut. cult to determine at which join point an aspect will execute. Simi- The concepts of pointcuts and advices open up new possibil- larly, when considering one join point, knowing which aspects will ities in terms of modularization, allowing for a clean separation execute there and in what order is non-trivial. This makes it difficult between base code and crosscutting concerns. However this sepa- to understand how the application will behave. A number of visu- ration makes it more difficult for a developer to assess system be- alization tools have been proposed that attempt to provide support havior. In particular, the implicit invocation mechanism introduces for such program understanding. However, they neither scale up to an additional layer of complexity in the construction of a system. large code bases nor scale down to understanding what happens at This can make it harder to understand how base system and aspects a single join point.
    [Show full text]
  • Comprehensive Aspect Weaving for Java
    Science of Computer Programming 76 (2011) 1015–1036 Contents lists available at ScienceDirect Science of Computer Programming journal homepage: www.elsevier.com/locate/scico Comprehensive aspect weaving for Java Alex Villazón ∗, Walter Binder, Philippe Moret, Danilo Ansaloni Faculty of Informatics, University of Lugano, CH-6900 Lugano, Switzerland article info a b s t r a c t Article history: Aspect-oriented programming (AOP) has been successfully applied to application code Received 20 July 2009 thanks to techniques such as Java bytecode instrumentation. Unfortunately, with existing Received in revised form 19 October 2009 AOP frameworks for Java such as AspectJ, aspects cannot be woven into the standard Java Accepted 2 December 2009 class library. This restriction is particularly unfortunate for aspects that would benefit Available online 29 April 2010 from comprehensive aspect weaving with complete method coverage, such as profiling or debugging aspects. In this article we present MAJOR, a new tool for comprehensive aspect Keywords: weaving, which ensures that aspects are woven into all classes loaded in a Java Virtual Aspect-oriented programming Aspect weaving Machine, including those in the standard Java class library. MAJOR includes the pluggable Bytecode instrumentation module CARAJillo, which supports efficient access to a complete and customizable calling Profiling context representation. We validate our approach with three case studies. Firstly, we Debugging weave existing profiling aspects with MAJOR which otherwise would generate incomplete Detecting memory leaks profiles. Secondly, we introduce an aspect for memory leak detection that also benefits Recreating crashing conditions from comprehensive weaving. Thirdly, we present an aspect subsuming the functionality Java Virtual Machine of ReCrash, an existing tool based on low-level bytecode instrumentation techniques that generates unit tests to reproduce program failures.
    [Show full text]
  • A Comparison of Context-Oriented and Aspect-Oriented Programming
    A comparison of Context-Oriented and Aspect-Oriented Programming Matthias Springer Hasso Plattner Institute, Advanced Modularity, seminar paper Abstract. Aspect-oriented programming and context-oriented program- ming were designed to modularize cross-cutting concerns that would oth- erwise lead to scattered code. We illustrate conceptual differences be- tween aspect-oriented programming and context-oriented programming in order to point out which technique should be used for a given use case. Besides, we motivate that pointcuts and immediate layer activation no- tifications can be useful in context-oriented programming. 1 Software development for mobile devices In this paper, we will compare aspect-oriented programming and context-oriented programming, two techniques for modularizing cross-cutting concerns. We will show two typical use cases in the area of mobile devices, immediate feedback and power management, that we will implement using aspect-oriented programming and context-oriented programming. 1.1 Immediate feedback Haptic feedback and auditive feedback are well-known patterns in human-com- puter interaction [7]. The idea is to provide immediate feedback to user input, such that the user can be certain that the device received the input. In this example the mobile device should vibrate for a quarter of a second after the user touched the touch screen or pressed a keyboard button or another hardware button. Alternatively, the device should play an unobtrusive click sound. 1.2 Power management Figure 1 shows four power states for a mobile device. If the battery charge level is 50% or greater, then the device is in the high battery state. In that state, no power saving mechanisms are activated, i.e.
    [Show full text]
  • An AOP Extension for C++
    Workshop Aspects AspectC++: Olaf Spinczyk Daniel Lohmann Matthias Urban an AOP Extension for C++ ore and more software developers are The aspect Tracing modularises the implementa- On the CD: getting in touch with aspect-oriented tion of output operations, which are used to trace programming (AOP). By providing the the control flow of the program. Whenever the exe- The evaluation version M means to modularise the implementation of cross- cution of a function starts, the following aspect prints of the AspectC++ Add- in for VisualStudio.NET cutting concerns, it stands for more reusability, its name: and the open source less coupling between modules, and better separa- AspectC++ Develop- tion of concerns in general. Today, solid tool sup- #include <cstdio> ment Tools (ACDT) port for AOP is available, for instance, by JBoss for Eclipse, as well as // Control flow tracing example example listings are (JBoss AOP), BEA (AspectWerkz), and IBM (As- aspect Tracing { available on the ac- pectJ) and the AJDT for Eclipse. However, all // print the function name before execution starts companying CD. these products are based on the Java language. advice execution ("% ...::%(...)") : before () { For C and C++ developers, none of the key players std::printf ("in %s\n", JoinPoint::signature ()); offer AOP support – yet. } This article introduces AspectC++, which is an as- }; pect-oriented language extension for C++. A compil- er for AspectC++, which transforms the source code Even without fully understanding all the syntactical into ordinary C++ code, has been developed as elements shown here, some big advantages of AOP an open source project. The AspectC++ project be- should already be clear from the example.
    [Show full text]
  • Efficient Late Binding of Dynamic Function Compositions
    Efficient Late Binding of Dynamic Function Compositions Lars Schütze Jeronimo Castrillon Chair for Compiler Construction Chair for Compiler Construction Technische Universität Dresden Technische Universität Dresden Dresden, Germany Dresden, Germany [email protected] [email protected] Abstract 1 Introduction Adaptive software becomes more and more important as Ubiquitous computing leads to new challenges where context- computing is increasingly context-dependent. Runtime adapt- dependent software is more and more important. Developing ability can be achieved by dynamically selecting and apply- such software requires approaches that focus on objects, their ing context-specific code. Role-oriented programming has context-dependent behavior and relations. Object-oriented been proposed as a paradigm to enable runtime adaptive soft- programming (OOP) is the de facto standard approach to ware by design. Roles change the objects’ behavior at run- those problems today. This is because of the comprehensi- time and thus allow adapting the software to a given context. bility of object-oriented models and code which enables an However, this increased variability and expressiveness has intuitive representation of aspects of the real world. That is a direct impact on performance and memory consumption. how classes, objects, functions and inheritance originated. We found a high overhead in the steady-state performance of For example, an aspect of the real world is that an object may executing compositions of adaptations. This paper presents appear in different roles at different times (i.e., contexts). To a new approach to use run-time information to construct a reflect the different roles of entities, design patterns have dispatch plan that can be executed efficiently by the JVM.
    [Show full text]
  • A Joint Point Interfaces for Safe and Flexible Decoupling of Aspects
    A Joint Point Interfaces for Safe and Flexible Decoupling of Aspects Eric Bodden, Technische Universität Darmstadt Éric Tanter, University of Chile Milton Inostroza, University of Chile In current aspect-oriented systems, aspects usually carry, through their pointcuts, explicit references to the base code. Those references are fragile and hinder important software engineering properties such as modular reasoning and independent evolution of aspects and base code. In this work, we introduce a novel abstraction called Join Point Interface, which, by design, aids modular reasoning and independent evolution by decoupling aspects from base code and by providing a modular type-checking algorithm. Join point in- terfaces can be used both with implicit announcement through pointcuts, and with explicit announcement, using closure join points. Join point interfaces further offer polymorphic dispatch on join points, with an advice-dispatch semantics akin to multi-methods. To support flexible join point matching, we incorporate into our language an earlier proposal for generic advice, and introduce a mechanism for controlled global quantification. We motivate each language feature in detail, showing that it is necessary to obtain a lan- guage design that is both type safe and flexible enough to support typical aspect-oriented programming idioms. We have implemented join point interfaces as an open-source extension to AspectJ. A case study on existing aspect-oriented programs supports our design, and in particular shows the necessity of both generic interfaces and some mechanism for global quantification. Categories and Subject Descriptors: D.2.3 [Software Engineering]: Coding Tools and Techniques; D.3.3 [Programming Languages]: Language Constructs and Features General Terms: Design, Languages Additional Key Words and Phrases: aspect-oriented programming, modularity, typing, interfaces, implicit announcement, explicit announcement, join point polymorphism, advice dispatch 1.
    [Show full text]
  • Analyzing Multi-Dimensional Programming in Aop and Composition Filters
    ANALYZING MULTI-DIMENSIONAL PROGRAMMING IN AOP AND COMPOSITION FILTERS Lodewijk M.J. Bergmans ([email protected]) Mehmet Aksit ([email protected]) http://trese.cs.utwente.nl TRESE GROUP – CENTRE FOR TELEMATICS AND INFORMATION TECHNOLOGY (CTIT) UNIVERSITY OF TWENTE, P.O. BOX 217, 7500 AE, ENSCHEDE, THE NETHERLANDS Abstract--In this paper, we investigate the meaning and impact of multi-dimensional construction of soft- ware, as exemplified by Aspect-Oriented Programming and Composition Filters. A simple application is introduced to illustrate the discussion topics. We conclude with a number of requirements for multi- dimensional programming. Lately, the software engineering field is increasingly becom- In this paper, we investigate the meaning and impact of ing aware of the need for better modeling techniques to be multi-dimensional construction of software with a few mod- able to design systems as compositions of independent con- eling approaches, notably aspect-oriented programming and cerns. Various models such as Adaptive Programming composition filters. [Mezini 98], Aspect-Oriented Programming [Kiczales 97], Subject-Oriented Programming [Harrison 93] and Composi- tion Filters [Aksit 88, 92, 94] have triggered and/or addressed 1. MODELING SOFTWARE this need. In particular Aspect-Oriented Programming (AOP) is gaining much interest recently. From a software-engineering point of view, a key require- ment of software development is to be able to construct a Previously, we have argued for extending AOP towards – system by combining modules
    [Show full text]
  • A Brief Tour of Join Point Interfaces
    A Brief Tour of Join Point Interfaces Eric Bodden Éric Tanter Milton Inostroza Secure Software Engineering PLEIAD Lab EC SPRIDE, TU Darmstadt, Germany Computer Science Dept (DCC) [email protected] University of Chile {etanter,minostro}@dcc.uchile.cl ABSTRACT As we show in Figure 1a, aspects with pointcuts and ad- In standard AspectJ, aspects and base code are often in- vice as in AspectJ cause implicit dependencies between as- sufficiently decoupled, as aspects hold pointcuts, which can pects and base code. This is because an aspect contains contain explicit textual references to base code. This hin- direct textual references to the base code via its pointcuts. ders aspect evolution and reuse, and may hinder reasoning These implicit dependencies, denoted by the dashed arrows about aspects on the base-code side. in the figure, make programs fragile, hinder aspect evolution In this demo we present join point interfaces as an ex- and reuse, and compromise separate development. Changes tension to the aspect-oriented programming language As- in the base code can unwittingly render aspects ineffective pectJ. Opposed to AspectJ, with join point interfaces as- or cause spurious advice applications. Conversely, a change pects and base code communicate only through a shared in a pointcut definition may cause parts of the base pro- interface abstraction. Aspects themselves go without point- gram to be advised without notice, breaking some implicit cuts and only reference the interface. Pointcuts are typically assumptions. This problem is known as the fragile pointcut defined on the base-code side, or not at all, as join point problem [4, 7].
    [Show full text]
  • Aspect-Oriented Programming and Aspectj
    What is Aspect-Oriented Programming? Many possible answers: • a fad • a way-too-general collection of cross-cutting Aspect-Oriented programming techniques Programming and AspectJ • a new name for old ideas (generators, domain- specific languages, MOPs) • Aspect-oriented programming is a common buzzword lately • the solution to all our problems • Papers from ECOOP 1997 (early overview— My opinion: AOP is just a new name for old the manifesto), ECOOP 2001 (overview of ideas, but these ideas are good AspectJ) - dominant AOP implementations (e.g., AspectJ) are MOP-like, but they don’t • Kiczales (the team leader) was behind the need to be CLOS MOP An aspect is a piece of functionality that cross- cuts functional units of a system 1 of 18 2 of 18 Yannis Smaragdakis Yannis Smaragdakis Simple Working Example (bad, IMO) Aspect-Oriented Principles • Image processing application with filters • A component is a part of the implementation - filters need to be kept separate that is localized in traditional languages (Java/ - filters need to be fused together for C/C++, etc.) optimization (e.g., loop fusion) • An aspect is a part of the implementation that (defun or! (a b) is not well-localized with traditional languages (let ((result (new-image))) (code ends up being scattered everywhere) (loop for i from 1 to width do (loop for j from 1 to height do • AOP tries to offer language support for (set-pixel result i j expressing aspects concisely and separately (or (get-pixel a i j) (get-pixel b i j))))) from components result)) • Join points: the points
    [Show full text]
  • Aspect-Oriented Instrumentation with GCC
    Formal Methods in System Design manuscript No. (will be inserted by the editor) INTERASPECT: Aspect-Oriented Instrumentation with GCC Justin Seyster · Ketan Dixit · Xiaowan Huang · Radu Grosu · Klaus Havelund · Scott A. Smolka · Scott D. Stoller · Erez Zadok Received: date / Accepted: date Abstract We present the INTERASPECT instrumentation framework for GCC, a widely used compiler infrastructure. The addition of plug-in support in the latest release of GCC makes it an attractive platform for runtime instrumentation, as GCC plug-ins can directly add instrumentation by transforming the compiler’s intermediate representation. Such trans- formations, however, require expert knowledge of GCC internals. INTERASPECT addresses this situation by allowing instrumentation plug-ins to be developed using the familiar vo- cabulary of Aspect-Oriented Programming: pointcuts, join points, and advice functions. Moreover, INTERASPECT uses specific information about each join point in a pointcut, possibly including results of static analysis, to support powerful customized instrumenta- tion. We describe the INTERASPECT API and present several examples that illustrate its practical utility as a runtime-verification platform. We also introduce a tracecut system that uses INTERASPECT to construct program monitors that are formally specified as regular expressions. Keywords program instrumentation, aspect-oriented programming, GCC, monitoring, tracecut 1 Introduction GCC is a widely used compiler infrastructure that supports a variety of input languages, e.g., C, C++, Fortran, Java, and Ada, and over 30 different target machine architectures. GCC translates each of its front-end languages into a language-independent intermediate representation called GIMPLE, which then gets translated to machine code for one of GCC’s many target architectures.
    [Show full text]
  • An Overview of Aspectj
    An Overview of AspectJ Gregor Kiczales1, Erik Hilsdale2, Jim Hugunin2, Mik Kersten2, Jeffrey Palm2 and William G. Griswold3 1 Department of Computer Science, University of British Columbia, 201-2366 Main Mall, Vancouver, BC V6T 1Z4 Canada [email protected] 2 Xerox Palo Alto Research Center 3333 Coyote Hill Road, Palo Alto, CA 94304 USA (hilsdale, hugunin, mkersten, palm)@parc.xerox.com 3 Department of Computer Science and Engineering, University of California, San Diego La Jolla, CA 92093 USA [email protected] Abstract. AspectJ™ 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. 1 Introduction Aspect-oriented programming (AOP) [14] has been proposed as a technique for improving separation of concerns in software.1 AOP builds on previous technologies, including procedural programming and object-oriented programming, that have already made significant improvements in software modularity.
    [Show full text]