124,034 research outputs found
A Transformational Reengineering System That Supports Software Maintenance Using a Graph Representation for the Identification of an Object-Oriented Software Architecture.
The process of maintenance and enhancement of legacy software systems is a laborious and unavoidable task. Often these systems lack structure or modularity, as they were developed using programming languages and paradigms that do not incorporate object-oriented features and sound design principles. The software engineer\u27s task can be simplified if tools are available to identify object like features in the code. These tools can help transform the non-object-oriented code to object oriented code. This research describes a comprehensive and systematic process for transformational reengineering of legacy systems. Research in reengineering is mainly focused on clustering techniques that group procedures present in the legacy system into candidate objects. These clustering approaches are limited to systems with well-defined data structures and procedures. Several of these approaches are either not comprehensive, limited to certain types of systems, or depend extensively on engineer knowledge of the system. Unlike these approaches that analyze legacy systems at the procedural level, the reengineering process we present analyzes systems at the statement level. This process results in the identification of object operations. These operations, along with the state variables and the user defined data structures, are arranged in a hierarchy that represents the object structure of the reengineered variant of the legacy system. From this system hierarchy, objects are identified and encapsulated by streamlining the interfaces. The reengineering process is incorporated in a tool, ReArchitect. Programs are statically analyzed and represented as a statement dependence graph (StDG) for further processing. The StDG is a fine-grained representation with modular representation for functions and program slices. It can adapt to program changes, unlike other representations. The StDG is restructured by merging cohesive components in the graph. The restructured graph is used to build the object structure, which is used to identify the objects. The StDG is a theoretically sound framework that provides support for many problems found in the reengineering domain. We show the value of the StDG in two such domains: program slicing and maintenance. The StDG is restructured differently for different requirements (space/time), and for different types of applications
Pattern Reification as the Basis for Description-Driven Systems
One of the main factors driving object-oriented software development for
information systems is the requirement for systems to be tolerant to change. To
address this issue in designing systems, this paper proposes a pattern-based,
object-oriented, description-driven system (DDS) architecture as an extension
to the standard UML four-layer meta-model. A DDS architecture is proposed in
which aspects of both static and dynamic systems behavior can be captured via
descriptive models and meta-models. The proposed architecture embodies four
main elements - firstly, the adoption of a multi-layered meta-modeling
architecture and reflective meta-level architecture, secondly the
identification of four data modeling relationships that can be made explicit
such that they can be modified dynamically, thirdly the identification of five
design patterns which have emerged from practice and have proved essential in
providing reusable building blocks for data management, and fourthly the
encoding of the structural properties of the five design patterns by means of
one fundamental pattern, the Graph pattern. A practical example of this
philosophy, the CRISTAL project, is used to demonstrate the use of
description-driven data objects to handle system evolution.Comment: 20 pages, 10 figure
An introduction to Graph Data Management
A graph database is a database where the data structures for the schema
and/or instances are modeled as a (labeled)(directed) graph or generalizations
of it, and where querying is expressed by graph-oriented operations and type
constructors. In this article we present the basic notions of graph databases,
give an historical overview of its main development, and study the main current
systems that implement them
An Empirical Study of a Repeatable Method for Reengineering Procedural Software Systems to Object- Oriented Systems
This paper describes a repeatable method for reengineering a procedural
system to an object-oriented system. The method uses coupling metrics to assist a domain
expert in identifying candidate objects. An application of the method to a simple program
is given, and the effectiveness of the various coupling metrics are discussed. We perform
a detailed comparison of our repeatable method with an ad hoc, manual reengineering
effort based on the same procedural program. The repeatable method was found to be
effective for identifying objects. It produced code that was much smaller, more efficient,
and passed more regression tests than the ad hoc method. Analysis of object-oriented
metrics indicated both simpler code and less variability among classes for the repeatable
method
Object oriented execution model (OOM)
This paper considers implementing the Object Oriented Programming Model directly in the hardware to serve as a base to exploit object-level parallelism, speculation and heterogeneous computing. Towards this goal, we present a new execution model called Object
Oriented execution Model - OOM - that implements the OO Programming Models. All OOM hardware structures are objects and the OOM Instruction Set directly utilizes objects while hiding other complex hardware structures. OOM maintains all high-level programming language information until execution time. This enables efficient
extraction of available parallelism in OO serial code at
execution time with minimal compiler support. Our results
show that OOM utilizes the available parallelism better
than the OoO (Out-of-Order) modelPeer ReviewedPostprint (published version
Structural Analysis: Shape Information via Points-To Computation
This paper introduces a new hybrid memory analysis, Structural Analysis,
which combines an expressive shape analysis style abstract domain with
efficient and simple points-to style transfer functions. Using data from
empirical studies on the runtime heap structures and the programmatic idioms
used in modern object-oriented languages we construct a heap analysis with the
following characteristics: (1) it can express a rich set of structural, shape,
and sharing properties which are not provided by a classic points-to analysis
and that are useful for optimization and error detection applications (2) it
uses efficient, weakly-updating, set-based transfer functions which enable the
analysis to be more robust and scalable than a shape analysis and (3) it can be
used as the basis for a scalable interprocedural analysis that produces precise
results in practice.
The analysis has been implemented for .Net bytecode and using this
implementation we evaluate both the runtime cost and the precision of the
results on a number of well known benchmarks and real world programs. Our
experimental evaluations show that the domain defined in this paper is capable
of precisely expressing the majority of the connectivity, shape, and sharing
properties that occur in practice and, despite the use of weak updates, the
static analysis is able to precisely approximate the ideal results. The
analysis is capable of analyzing large real-world programs (over 30K bytecodes)
in less than 65 seconds and using less than 130MB of memory. In summary this
work presents a new type of memory analysis that advances the state of the art
with respect to expressive power, precision, and scalability and represents a
new area of study on the relationships between and combination of concepts from
shape and points-to analyses
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