The term aspect-oriented programming (AOP) has come to describe the set of programming mechanisms developed specifically to express crosscutting concerns. Since crosscutting concerns cannot be properly modularized wit...
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The term aspect-oriented programming (AOP) has come to describe the set of programming mechanisms developed specifically to express crosscutting concerns. Since crosscutting concerns cannot be properly modularized within object-oriented programming, they are expressed as aspects and are composed, or woven, with traditionally encapsulated functionality referred to as components. Many AOP models exist, but their implementations are typically coupled with a single language. To allow weaving of existing components with aspects written in the language of choice, AOP requires a language-independent tool. This paper presents ***, a load-time weaver that allows aspects and components to be written in a variety of languages and freely intermixed. *** relies on XML to specify aspect bindings and standardized Common language Infrastructure to avoid coupling aspects or components with a particular language. By demonstrating language-independence, *** provides a migration path to the AOP paradigm by preserving existing developer knowledge, tools, and software components. The tool's capabilities are demonstrated with logging aspects written in and applied to Visual Basic and C# components.
Empirical program optimizers estimate the values of key optimization parameters by generating different program versions and running them on the actual hardware to determine which values give the best performance. In ...
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ISBN:
(纸本)9781581136623
Empirical program optimizers estimate the values of key optimization parameters by generating different program versions and running them on the actual hardware to determine which values give the best performance. In contrast, conventional compilers use models of programs and machines to choose these parameters. It is widely believed that model-driven optimization does not compete with empirical optimization, but few quantitative comparisons have been done to date. To make such a comparison, we replaced the empirical optimization engine in ATLAS (a system for generating a dense numerical linear algebra library called the BLAS) with a model-driven optimization engine that used detailed models to estimate values for optimization parameters, and then measured the relative performance of the two systems on three different hardware platforms. Our experiments show that model-driven optimization can be surprisingly effective, and can generate code whose performance is comparable to that of code generated by empirical optimizers for the BLAS.
Concurrent programming is notoriously difficult. Current abstractions are intricate and make it hard to design computer systems that are reliable and scalable. We argue that these problems can be addressed by moving t...
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Concurrent programming is notoriously difficult. Current abstractions are intricate and make it hard to design computer systems that are reliable and scalable. We argue that these problems can be addressed by moving to a declarative style of concurrency control in which programmers directly indicate the safety properties that they require. In our scheme the programmer demarks sections of code which execute within lightweight software-based transactions that commit atomically and exactly once. These transactions can update shared data, instantiate objects, invoke library features and so on. They can also block, waiting for arbitrary boolean conditions to become true. Transactions which do not access the same shared memory locations can commit concurrently. Furthermore, in general, no performance penalty is incurred for memory accesses outside transactions. We present a detailed design of this proposal along with an implementation and evaluation. We argue that the resulting system (i) is easier for mainstream programmers to use, (ii) prevents lock-based priority-inversion and deadlock problems and (iii) can offer performance advantages.
Distinguishing non-null references from possibly-null references at the type level can detect null-related errors in object-oriented programs at compile-time. This paper gives a proposal for retrofitting a language su...
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Distinguishing non-null references from possibly-null references at the type level can detect null-related errors in object-oriented programs at compile-time. This paper gives a proposal for retrofitting a language such as C# or Java with non-null types. It addresses the central complications that arise in constructors, where declared non-null fields may not yet have been initialized, but the partially constructed object is already accessible. The paper reports experience with an implementation for annotating and checking null-related properties in C# programs.
Many modem programminglanguages support basic generic programming, sufficient to implement type-safe polymorphic containers. Some languages have moved beyond this basic support to a broader, more powerful interpretat...
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Many modem programminglanguages support basic generic programming, sufficient to implement type-safe polymorphic containers. Some languages have moved beyond this basic support to a broader, more powerful interpretation of generic programming, and their extensions have proven valuable in practice. This paper reports on a comprehensive comparison of generics in six programminglanguages: C++, Standard NIL, Haskell, Eiffel, Java (with its proposed generics extension), and Generic C#. By implementing a substantial example in each of these languages, we identify eight language features that support this broader view of generic programming. We find these features are necessary to avoid awkward designs, poor maintainability, unnecessary run-time checks, and painfully verbose code. As languages increasingly support generics, it is important that languagedesigners understand the features necessary to provide powerful generics and that their absence causes serious difficulties for programmers.
This paper presents a comprehensive, domain-driven framework for software development. It consists of a meta-programmable domain specific modeling environment and a model transformation generator toolset based on grap...
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ISBN:
(纸本)1581137516
This paper presents a comprehensive, domain-driven framework for software development. It consists of a meta-programmable domain specific modeling environment and a model transformation generator toolset based on graph transformations. The framework allows the creation of custom, domain-oriented programming environments that support end-user programmability. In addition, the framework could be considered an early, end-to-end implementation of the concepts advocated by the OMG's Model Driven Architecture initiative.
This paper describes a method for transforming any given set of Datalog rules into an efficient specialized implementation with guaranteed worst-case time and space complexities, and for computing the complexities fro...
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ISBN:
(纸本)1581137052
This paper describes a method for transforming any given set of Datalog rules into an efficient specialized implementation with guaranteed worst-case time and space complexities, and for computing the complexities from the rules. The running time is optimal in the sense that only useful combinations of facts that lead to all hypotheses of a rule being simultaneously true are considered, and each such combination is considered exactly once. The associated space usage is optimal in that it is the minimum space needed for such consideration modulo scheduling optimizations that may eliminate some summands in the space usage formula. The transformation is based on a general method for algorithm design that exploits fixed-point computation, incremental maintenance of invariants, and combinations of indexed and linked data structures. We apply the method to a number of analysis problems, some with improved algorithm complexities and all with greatly improved algorithm understanding and greatly simplified complexity analysis.
JPie is a tightly integrated development environment supporting live object-oriented software construction in Java. JPie embodies the notion of a dynamic class whose signature and implementation can be modified at run...
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ISBN:
(纸本)1581137516
JPie is a tightly integrated development environment supporting live object-oriented software construction in Java. JPie embodies the notion of a dynamic class whose signature and implementation can be modified at run time, with changes taking effect immediately upon existing instances of the class. The result is complete elimination of the edit-compile-test cycle. JPie users create and modify class definitions through direct manipulation of visual representations of program abstractions. This support is provided without modification of the language or run-time system. In this demonstration, we illustrate central features of JPie through the construction of a sample application. These include dynamic declaration of instance variables and methods, dynamic modification of method bodies and threads, dynamic user interface construction and event handling, and on-the-fly exception handling in JPie's integrated thread-oriented debugger.
Software connectors are increasingly recognized as an important consideration in the design and implementation of object-oriented software systems. Connectors can be used to communicate across a distributed system, co...
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ISBN:
(纸本)3540405313
Software connectors are increasingly recognized as an important consideration in the design and implementation of object-oriented software systems. Connectors can be used to communicate across a distributed system, coordinate the activities of several objects, or adapt one object's interface to the interface of another. Mainstream object-oriented languages, however, do not provide explicit support for connectors. As a result, connection code is intermingled with application code, making it difficult to understand, evolve, and reuse connection mechanisms. In this paper, we add language support for user-defined connectors to the ArchJava language. Our design enables a wide range of connector abstractions, including caches, events, streams, and remote method calls. Developers can describe both the run-time semantics of connectors and the typechecking semantics. The connector abstraction supported by ArchJava cleanly separates reusable connection code from application logic, making the semantics of connections more explicit and allowing engineers to easily change the connection mechanisms used in a program. We evaluate the expressiveness and the engineering benefits of our design in a case study applying ArchJava to the PlantCare ubiquitous computing application.
作者：
Parnas, DLUniv Limerick
Coll Elect & Informat Software Qual Res Lab Dept Comp Sci & Informat Syst Limerick Ireland
Software Engineering is discussed as a branch of Engineering specialising in software intensive products. The process of developing good software is discussed and it is argued that writing programs, though obviously a...
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Software Engineering is discussed as a branch of Engineering specialising in software intensive products. The process of developing good software is discussed and it is argued that writing programs, though obviously an essential step in the process, is only a small part of Software Engineering. (C) 2003 Elsevier B.V. All rights reserved.
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