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Classbox/J: Controlling the scope of change in Java

acm sigplan NOTICES 2005年第10期40卷 177-189页

作者： Bergel, A Ducasse, S Nierstrasz, O Univ Bern Software Composit Grp Bern Switzerland Univ Savoie Language & Software Evolut Grp LISTIC Chambery France

Unanticipated changes to complex software systems can introduce anomalies such as duplicated code, suboptimal inheritance relationships and a proliferation of run-tirne downcasts. Refactoring to eliminate these anomalies may not be an option, at least in certain stages of software evolution. Classboxes are modules that restrict the visibility of changes to selected clients only, thereby offering more freedom in the way unanticipated changes may be implemented, and thus reducing the need for convoluted design anomalies. In this paper we demonstrate how classboxes can be implemented in statically-typed languages like Java. We also present an extended case study of Swing, a Java GUI package built on top of AWT, and we document the ensuing anomalies that Swing introduces. We show how Classbox/J, a prototype implementation of classboxes for Java, is used to provide a cleaner implementation of Swing using local refinement rather than subclassing.

关键词： language design module package open-classes class extension

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Event-Driven Network programming

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acm sigplan NOTICES 2016年第6期51卷 369-385页

作者： McClurg, Jedidiah Hojjat, Hossein Foster, Nate Cerny, Pavol CU Boulder Boulder CO 80309 USA Cornell Univ Ithaca NY 14853 USA

Software-defined networking (SDN) programs must simultaneously describe static forwarding behavior and dynamic updates in response to events. Event-driven updates are critical to get right, but difficult to implement correctly due to the high degree of concurrency in networks. Existing SDN platforms offer weak guarantees that can break application invariants, leading to problems such as dropped packets, degraded performance, security violations, etc. This paper introduces event-driven consistent updates that are guaranteed to preserve well-defined behaviors when transitioning between configurations in response to events. We propose network event structures (NESs) to model constraints on updates, such as which events can be enabled simultaneously and causal dependencies between events. We define an extension of the NetKAT language with mutable state, give semantics to stateful programs using NESs, and discuss provably-correct strategies for implementing NESs in SDNs. Finally, we evaluate our approach empirically, demonstrating that it gives well-defined consistency guarantees while avoiding expensive synchronization and packet buffering.

关键词： network update consistent update event structure software-defined networking SDN NetKAT

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EXPLORER : Query- and Demand-Driven Exploration of Interprocedural Control Flow Properties

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acm sigplan NOTICES 2015年第10期50卷 520-534页

作者： Feng, Yu Wang, Xinyu Dillig, Isil Lin, Calvin Univ Texas Austin Austin TX 78712 USA

This paper describes a general framework-and its implementation in a tool called EXPLORER-for statically answering a class of interprocedural control flow queries about Java programs. EXPLORER allows users to formulate queries about feasible callstack configurations using regular expressions, and it employs a precise, demand-driven algorithm for answering such queries. Specifically, EXPLORER constructs an automaton A that is iteratively refined until either the language accepted by A is empty (meaning that the query has been refuted) or until no further refinement is possible based on a precise, context-sensitive abstraction of the program. We evaluate EXPLORER by applying it to three different program analysis tasks, namely, (1) analysis of the observer design pattern in Java, (2) identification of a class of performance bugs, and (3) analysis of inter-component communication in Android applications. Our evaluation shows that EXPLORER is both efficient and precise.

关键词： Algorithms languages Program analysis Demand-driven analysis points-to analysis query language control flow properties

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programming by sketching for bit-streaming programs

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acm sigplan NOTICES 2005年第6期40卷 281-294页

作者： Solar-Lezama, A Rabbah, R Bodík, R Ebcioglu, K Univ Calif Berkeley Div Comp Sci Berkeley CA 94720 USA MIT Comp Sci & Artificial Intelligence Lab Cambridge MA 02139 USA IBM Corp TJ Watson Res Ctr Armonk NY 10504 USA

This paper introduces the concept of programming with sketches, an approach for the rapid development of high-performance applications. This approach allows a programmer to write clean and portable reference code, and then obtain a high-quality implementation by simply sketching the outlines of the desired implementation. Subsequently, a compiler automatically fills in the missing details while also ensuring that a completed sketch is faithful to the input reference code. In this paper, we develop StreamBit as a sketching methodology for the important class of bit-streaming programs (e.g., coding and cryptography). A sketch is a partial specification of the implementation, and as such, it affords several benefits to programmer in terms of productivity and code robustness. First, a sketch is easier to write compared to a complete implementation. Second, sketching allows the programmer to focus on exploiting algorithmic properties rather than on orchestrating low-level details. Third, a sketch-aware compiler rejects "buggy" sketches, thus improving reliability while allowing the programmer to quickly evaluate sophisticated implementation ideas. We evaluated the productivity and performance benefits of our programming methodology in a user-study, where a group of novice StreamBit programmers competed with a group of experienced C programmers on implementing a cipher. We learned that, given the same time budget, the ciphers developed in StreamBit ran 2.5 x faster than ciphers coded in C. We also produced implementations of DES and Serpent that were competitive with hand optimized implementations available in the public domain.

关键词： stream programming StreamIt synchronous dataflow sketching domain specific language domain specific compiler

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Higher-Order and Tuple-Based Massively-Parallel Prefix Sums

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acm sigplan NOTICES 2016年第6期51卷 539-552页

作者： Maleki, Sepideh Yang, Annie Burtscher, Martin Texas State Univ Dept Comp Sci San Marcos TX 78666 USA

Prefix sums are an important parallel primitive, especially in massively-parallel programs. This paper discusses two orthogonal generalizations thereof, which we call higher-order and tuple-based prefix sums. Moreover, it describes and evaluates SAM, a GPU-friendly algorithm for computing prefix sums and other scans that directly supports higher orders and tuple values. Its templated CUDA implementation unifies all of these computations in a single 100-statement kernel. SAM is communication-efficient in the sense that it minimizes main-memory accesses. When computing prefix sums of a million or more values, it outperforms Thrust and CUDPP on both a Titan X and a K40 GPU. On the Titan X, SAM reaches memory-copy speeds for large input sizes, which cannot be surpassed. SAM outperforms CUB, the currently fastest conventional prefix sum implementation, by up to a factor of 2.9 on eighth-order prefix sums and by up to a factor of 2.6 on eight-tuple prefix sums.

关键词： Algorithms Performance design Higher-order prefix sums tuple-based prefix sums carry propagation GPU programming

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AtomCaml: First-class atomicity via rollback

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acm sigplan NOTICES 2005年第9期40卷 92-104页

作者： Ringenburg, MF Grossman, D Univ Washington Dept Comp Sci & Engn Seattle WA 98195 USA

We have designed, implemented, and evaluated AtomCaml, an extension to Objective Caml that provides a synchronization primitive for atomic (transactional) execution of code. A first-class primitive function of type (unit -> 'a) -> 'a evaluates its argument (which may call other functions, even external C functions) as though no other thread has interleaved execution. Our design ensures fair scheduling and obstruction-freedom. Our implementation extends the Objective Cam] bytecode compiler and run-time system to support atomicity. A logging-and-rollback approach lets us undo uncompleted atomic blocks upon thread pre-emption, and retry them when the thread is rescheduled. The mostly functional nature of the Caml language and the Objective Caml implementation's commitment to a uniprocessor execution model (i.e., threads are interleaved, not executed simultaneously) allow particularly efficient logging. We have evaluated the efficiency and ease-of-use of AtomCaml by writing libraries and microbenchmarks, writing a small application, and replacing all locking with atomicity in an existing, large multithreaded application. Our experience indicates the performance overhead is negligible, atomic helps avoid synchronization mistakes, and idioms such as condition variables adapt reasonably to the atomic approach.

关键词： languages atomicity transactions concurrent programming Objective Caml

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Parametric polymorphism for software component architectures

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acm sigplan NOTICES 2005年第10期40卷 147-166页

作者： Oancea, CE Watt, SM Univ Western Ontario Dept Comp Sci London ON Canada

Parametric polymorphism has become a common feature of mainstream programming languages, but software component architectures have lagged behind and do not support it. We examine the problem of providing parametric polymorphism with components combined from different programming languages. We have investigated how to resolve different binding times and parametrization semantics in a range of representative languages and have identified a common ground that can be suitably mapped to different language bindings. We present a generic component architecture extension that provides support for parameterized components and that can be easily adapted to work oil top of various software component architectures in use today (e.g., CORBA, DCOM, JNI). We have implemented and tested this architecture on top Of CORBA. We also present Generic Interface Definition language (GIDL), an extension to CORBA-IDL supporting generic types and we describe language bindings for C++, Java and Aldor. We explain our implementation of GIDL, consisting of a GIDL to IDL compiler and tools for generating linkage code under the language bindings. We demonstrate how this architecture can be used to access C++'s STL, and Aldor's BasicMath libraries in a multi-language environment and discuss our mappings in the context of automatic library interface generation.

关键词： languages design antiunification generics parametric polymorphisrn software component architecture templates

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Sketching concurrent data structures

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acm sigplan NOTICES 2008年第6期43卷 136-148页

作者： Solar-Lezama, Armando Jones, Christopher Grant Bodik, Rastislav Univ Calif Berkeley Berkeley CA 94720 USA

We describe PSKETCH, a program synthesizer that helps programmers implement concurrent data structures. The system is based on the concept of sketching, a form of synthesis that allows programmers to express their insight about an implementation as a partial program: a sketch. The synthesizer automatically completes the sketch to produce an implementation that matches a given correctness criteria. PSKETCH is based on a new counterexample-guided inductive synthesis algorithm (CEGIS) that generalizes the original sketch synthesis algorithm from [ 20] to cope efficiently with concurrent programs. The new algorithm produces a correct implementation by iteratively generating candidate implementations, running them through a verifier, and if they fail, learning from the counterexample traces to produce a better candidate;converging to a solution in a handful of iterations. PSKETCH also extends SKETCH with higher-level sketching constructs that allow the programmer to express her insight as a "soup" of ingredients from which complicated code fragments must be assembled. Such sketches can be viewed as syntactic descriptions of huge spaces of candidate programs ( over 1 0 8 candidates for some sketches we resolved). We have used the PSKETCH system to implement several classes of concurrent data structures, including lock-free queues and concurrent sets with fine-grained locking. We have also sketched some other concurrent objects including a sense-reversing barrier and a protocol for the dining philosophers problem;all these sketches resolved in under an hour.

关键词： languages design sketching synthesis concurrency SAT SPIN

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Program Synthesis from Polymorphic Refinement Types

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acm sigplan NOTICES 2016年第6期51卷 522-538页

作者： Polikarpova, Nadia Kuraj, Ivan Solar-Lezama, Armando MIT CSAIL Cambridge MA USA

We present a method for synthesizing recursive functions that provably satisfy a given specification in the form of a polymorphic refinement type. We observe that such specifications are particularly suitable for program synthesis for two reasons. First, they offer a unique combination of expressive power and decidability, which enables automatic verification-and hence synthesis-of nontrivial programs. Second, a type-based specification for a program can often be effectively decomposed into independent specifications for its components, causing the synthesizer to consider fewer component combinations and leading to a combinatorial reduction in the size of the search space. At the core of our synthesis procedure is a newalgorithm for refinement type checking, which supports specification decomposition. We have evaluated our prototype implementation on a large set of synthesis problems and found that it exceeds the state of the art in terms of both scalability and usability. The tool was able to synthesize more complex programs than those reported in prior work (several sorting algorithms and operations on balanced search trees), as well as most of the benchmarks tackled by existing synthesizers, often starting from a more concise and intuitive user input.

关键词： languages Verification Program Synthesis Functional programming Refinement Types Predicate Abstraction

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DAOP-ADL: An architecture description language for dynamic component and aspect-based development

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2nd International conference on Generative programming and Component Engineering, GPCE 2003

作者： Pinto, MÓnica Fuentes, Lidia Troya, Jose MarÍa Dpto. de Lenguajes y Ciencias de la Computación University of Málaga Málaga Spain

ISBN: (纸本)3540201025

Architecture description languages deal with the description, analysis and reuse of software architectures. This paper describes DAOP-ADL, a component- and aspect-based language to specify the architecture of an application in terms of components, aspects and a set of plug-compatibility rules between them. With the aim of connecting the specification of the application architecture to the implementation, we describe our language using XML and XML Schemas. The DAOP-ADL language was designed to be interpreted by DAOP, our own dynamic component- and aspect-oriented platform. DAOP provides a composition mechanism that plugs aspects into components dynamically at runtime. The software architect will use the DAOP-ADL language at design time to describe the architecture of the application. Later this architectural information is loaded into the DAOP platform, which needs it to establish the dynamic connections between autonomous components and aspects. Therefore, the use of DAOP-ADL closes the gap between design and implementation of component- and aspect-based applications. © Springer-Verlag Berlin Heidelberg 2003.

关键词： XML

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