共查询到20条相似文献，搜索用时 15 毫秒
1.
This paper develops a formalism that precisely characterizes when class tables are required for C++ memory layouts. A memory layout is a particular choice of data structures for implementing run‐time support for object‐oriented languages. We use this formalism to quantify and evaluate, on a set of benchmarks, the space overhead for a set of C++ memory layouts. In particular, this paper studies the space overhead due to three language features: virtual dispatch, virtual inheritance, and dynamic typing. To date, there has been no scientific quantification or evaluation of C++ memory layouts. Our approach can help C++ implementors. This work has already influenced the memory layout design choices in IBM's Visual Age C++ V5 compiler. Applying our approach to a set of five benchmarks, we demonstrate that the impact of object‐oriented space overhead can vary dramatically between applications (ranging from 0.42% to 99.79% for our benchmarks). In particular, applications whose object space is dominated by instances of classes that heavily use object‐oriented language features will be significantly impacted by the choice of a memory layout. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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FC++ is a library for programming functionally in C++. Compared to other C++ functional programming libraries, FC++ is distinguished by its powerful type system which allows the manipulation of parametrically polymorphic functions (e.g., passing them as arguments to other functions and returning them as results). In this paper, we show how FC++ can be used in common object‐oriented programming tasks. We demonstrate FC++ implementations of several common design patterns (Adapter, Builder, Command, and more). Compared to conventional C++ implementations of these patterns, our implementations are either simpler (in that fewer classes/dependencies are needed), more efficient, or more type‐safe (thanks to parametric polymorphism and type inference). Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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Joseph R. Laracy 《Software》2009,39(1):105-110
As the use of computer simulation grows in a variety of science and engineering fields, the quality of random variate generators becomes increasingly important. Unfortunately, a number of standard implementations are grossly inadequate and exhibit poor statistical properties. This paper presents a software pattern for efficiently implementing an extensible, high‐quality random variate generator. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
4.
This paper describes a refactoring process that transforms a Java source code base into a functionally equivalent AspectJ source code base. The process illustrates the use of a collection of refactorings for aspect‐oriented source code, covering the extraction of scattered implementation elements to aspects, the internal reorganization of the extracted aspects and the extraction of commonalities to super‐aspects. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
5.
Although constraint programming has attracted much attention in logic programming, nowadays the importance to integrate constraints with imperative programming is widely acknowledged. In particular, in artificial intelligence domains, the benefits deriving from merging constraint‐based programming with object‐oriented paradigms seem to be still more attractive because of the lack of ‘pure’ AI languages in supporting structured representations. This work presents the extension of the Java language towards finite domain constraint programming. This extension has been possible thanks to a high‐level approach to low‐level resource management: the sleeper mechanism. As practical results, this paper shows how Java programmers can develop meaningful applications in which finite domain constraints have been extensively used, as in the design of visual, interactive, user‐interface environments in a client–server architecture. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
6.
The JR concurrent programming language extends Java with a richer concurrency model, by adding several new types and statements. JR provides dynamic remote virtual machine creation, dynamic remote object creation, remote method invocation, dynamic process creation, rendezvous, asynchronous message passing, semaphores, concurrent invocation, and shared variables. This paper presents RJ, a package for Java that provides JR‐like features. The paper gives an overview of RJ and its key features; describes the implications of RJ's design, including how RJ provides additional, useful flexibility; discusses the implementation of RJ; and gives qualitative and quantitative evaluations of our work with respect to feasibility and usability, experimentation, migration, and performance. RJ has been successful in meeting these goals and in providing insight into the trade‐offs between using a concurrent programming language versus using the equivalent concurrent package. Our work has yielded a few surprises in dealing with some concurrent programming language features, in understanding the run‐time performances of JR versus RJ programs, and in obtaining some additional, useful flexibility for concurrent programming applications. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
7.
Ronald F. Brender 《Software》2002,32(10):955-981
The BLISS programming language was invented by William A. Wulf and others at Carnegie‐Mellon University in 1969, originally for the DEC PDP‐10. BLISS‐10 caught the interest of Ronald F. Brender of DEC (Digital Equipment Corporation). After several years of collaboration, including the creation of BLISS‐11 for the PDP‐11, BLISS was adopted as DEC's implementation language for use on its new line of VAX computers in 1975. DEC developed a completely new generation of BLISSs for the VAX, PDP‐10 and PDP‐11, which became widely used at DEC during the 1970s and 1980s. With the creation of the Alpha architecture in the early 1990s, BLISS was extended again, in both 32‐ and 64‐bit flavors. BLISS support for the Intel IA‐32 architecture was introduced in 1995 and IA‐64 support is now in progress. BLISS has a number of unusual characteristics: it is typeless, requires use of an explicit contents of operator (written as a period or ‘dot’), takes an algorithmic approach to data structure definition, has no goto , is an expression language, and has an unusually rich compile‐time language. This paper reviews the evolution and use of BLISS over its three decade lifetime. Emphasis is on how the language evolved to facilitate portable programming while retaining its initial highly machine‐specific character. Finally, the success of its characteristics are assessed. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
8.
Amnon H. Eden 《Information Systems Frontiers》2002,4(4):379-391
Progress was made in the understanding of object-oriented (O-O) design through the introduction of patterns of design and architecture. Few works, however, offer methods of precise specification for O-O design.This article provides a well-defined ontology and an underlying framework for the formal specification of O-O design: (1) We observe key design motifs in O-O design and architectures. (2) We provide a computational model in mathematical logic suitable for the discussion in O-O design. (3) We use our conceptual toolkit to analyze and compare proposed formalisms. 相似文献
9.
One of the techniques employed by programmers during the development process is the use of code and design conventions. These are rules‐of‐thumb or best practices that improve the maintainability of software applications. In general, these conventions are maintained manually by the programmer since automated support is usually restricted to the automatic generation of code. However, the late discovery of convention errors can result in significant costs due to the effort required to correct them. In order to facilitate the early detection of these errors, the Practical Preprocessor for Programming Conventions system, P³ (pronounced P3),is proposed. This tool acts as a preprocessor to the Java compiler by providing facilities for the maintenance of specific object‐oriented code conventions and design principles during the creation of Java programs. This paper presents the design and implementation of the P³ system and also the practical experience of using this facility in a University programming environment. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
10.
Michael Philippsen 《Concurrency and Computation》2000,12(10):917-980
During the last decade object‐oriented programming has grown from marginal influence into widespread acceptance. During the same period, progress in hardware and networking has changed the computing environment from sequential to parallel. Multi‐processor workstations and clusters are now quite common. Unnumbered proposals have been made to combine both developments. Always the prime objective has been to provide the advantages of object‐oriented software design at the increased power of parallel machines. However, combining both concepts has proven to be notoriously difficult. Depending on the approach, often key characteristics of either the object‐oriented paradigm or key performance factors of parallelism are sacrificed, resulting in unsatisfactory languages. This survey first recapitulates well‐known characteristics of both the object‐oriented paradigm and parallel programming, and then marks out the design space of possible combinations by identifying various interdependencies of key concepts. The design space is then filled with data points: for 111 proposed languages we provide brief characteristics and feature tables. Feature tables, the comprehensive bibliography, and web‐addresses might help in identifying open questions and preventing re‐inventions. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
11.
For many years systems engineers have produced traditional system requirements specifications containing shall‐statement requirements. The rapid adoption of use case modeling for capturing functional requirements in the software community has caused systems engineers to examine the utility of use case models for capturing system‐level functional requirements. A transition from traditional shall‐statement requirements to use case modeling has raised some issues and questions. This paper advocates a hybrid requirements process in which use case modeling and traditional shall‐statement requirements are applied together to effectively express both functional and nonfunctional requirements for complex, hierarchical systems. This paper also presents a practical method for extracting requirements from the use case text to produce a robust requirements specification. © 2004 Wiley Periodicals, Inc. Syst Eng 7: 303–319, 2004 相似文献
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Raed Shatnawi Wei Li James Swain Tim Newman 《Journal of Software: Evolution and Process》2010,22(1):1-16
An empirical study of the relationship between object‐oriented (OO) metrics and error‐severity categories is presented. The focus of the study is to identify threshold values of software metrics using receiver operating characteristic curves. The study used the three releases of the Eclipse project and found threshold values for some OO metrics that separated no‐error classes from classes that had high‐impact errors. Although these thresholds cannot predict whether a class will definitely have errors in the future, they can provide a more scientific method to assess class error proneness and can be used by engineers easily. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
14.
This paper presents a new approach to the use of design patterns for the reengineering of legacy code, using a mapping from procedural design patterns to object-oriented patterns. We show also how object-oriented design patterns can be formalised and correctness conditions for their application derived, in order to justify the preservation of functionality in the reengineering process. We give examples taken from case studies of reengineering legacy COBOL applications. 相似文献
15.
Server‐side component models such as Enterprise JavaBeans (EJB) add powerful abstractions to the bare ‘business objects’ layer in order to support a clean separation of server‐side application logic from other concerns such as distribution, security, transaction management and persistence. An improved separation of concerns is also the main goal of aspect‐oriented programming (AOP). This paper compares the two approaches and reasons about the possibility of substituting (parts of) component models using AOP mechanisms. We conclude that AOP is a promising approach to eliminate important shortcomings of the container‐based component approach. However, our analysis of concrete aspect‐oriented languages shows that current AOP technology is not yet mature enough to supersede component models. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
16.
Design solutions have been proposed to implement generic data structures, however such techniques dedicated to algorithms are not well known. This article discusses various recurrent problems encountered when designing reusable, extensible algorithms for operations research. It explains how to use object‐oriented concepts and the notion of genericity to design algorithms that are independent of the data structures and the algorithms they use, but that can still interact deeply with them. An object‐oriented design is sometimes considered to be less efficient than a classical one, and operations research is one of these scientific fields where efficiency really matters. Hence, the main goal of this article is to explain how to design algorithms that are both generic and efficient. It also discusses specific recurring design issues for operations research software and proposes solutions that improve the genericity of the algorithms. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
17.
This paper argues for the adoption of object‐oriented design and UML tools for nonsoftware designs, i.e., systems, hardware and algorithms: This is a controversial position. It presents a case study, the design of a heating, ventilation, and air conditioning system, using UML tools. This case study also shows the incremental elaboration used to progress from the requirements model, to the analysis model, to the design model, etc. The paper finally discusses some difficulties that must be overcome in order to apply UML tools to system designs. © 2002 Wiley Periodicals, Inc. Syst Eng 6: 28–48, 2003. 相似文献
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We present a linguistic construct to define concurrency control for the objects of an object database. This construct, calledconcurrent behavior, allows to define a concurrency control specification for each object type in the database; in a sense, it can be seen as a type extension. The concurrent behavior is composed by two parts: the first one, calledcommutativity specification, is a set of conditional rules, by which the programmer specifies when two methods do not conflict each other. The second part, the constraint specification, is a set of guarded regular expressions, calledconstraints, by which the programmer defines the allowed sequences of method calls. At each time during an actual execution, a subset of constraints may be active so limiting the external behavior of the object. A constraint becomesactive when its guard is verified, where a guard is composed of the occurrence of some method callm along with the verification of a boolean expression on the object state and the actual parameters ofm. A constraint dies when a string of the language corresponding to the regular expression has been recognized. While the commutativity specification is devoted to specify the way in which the external behavior of an object is influenced by the existence of concurrent transactions in the system, the constraint specification defines the behavior of the object, independently from the transactions. Since the two parts of the concurrent behavior are syntactically distinct and, moreover, each of them consists of a set of independent rules, modularity in specifying the objects is enhanced, with respect to a unique specification. We outline an implementation of the construct, which is based on a look-ahead policy: at each method execution, we foresee the admissible successive behaviors of the object, instead of checking the admission of each request at the time it is actually made. 相似文献
20.
新疆高校的学生存在族别的多样性、基础理论水平层次的不等性、中小学阶段接受教育时语言的异样性等诸多问题。如何在讲授一门课后使不同水平的学生达到基本统一的教学目标,对教师能够设计出面向对象的、合理的课程实施模式提出了严峻的挑战。文章详细阐述了Java语言程序设计课程实验教学模式研究成果与教学各环节的实施模式。 相似文献