This paper considers the garbage collection of concurrent objects for which it is necessary to know not only “reachability,” the usual criterion for reclaiming data, but also the “state” (active or blocked) of the...
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ISBN:
(纸本)9780897914116
This paper considers the garbage collection of concurrent objects for which it is necessary to know not only “reachability,” the usual criterion for reclaiming data, but also the “state” (active or blocked) of the object. For the actor model, a more comprehensive definition than previously available is given for reclaimable actors. Two garbage collection algorithms, implementing a set of “coloring” rules, are presented and their computational complexity is analyzed. Extensions are briefly described to allow incremental, concurrent, distributed and real-time collection. It is argued that the techniques used for the actor model applies to other object-based concurrent models.
The paper presents a discussion and a specification of an exception handling system dedicated to object-orientedprogramming. We show how a full object-oriented representation of exceptions and of protocols to handle ...
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ISBN:
(纸本)9780897914116
The paper presents a discussion and a specification of an exception handling system dedicated to object-orientedprogramming. We show how a full object-oriented representation of exceptions and of protocols to handle them, using meta-classes, makes the system powerful as well as extendible and solves many classical exception handling issues. We explain the interest for object-orientedprogramming of handlers attached to classes and to expressions. We propose an original algorithm for propagating exceptions along the invocation chain which takes into account, at each stack level, both kind of handlers. Any class can control which exceptions will be propagated out of its methods; any method can provide context-dependant answers to exceptional events. The whole specification and some keys of our Smalltalk implementation are presented in the paper.
This paper demonstrates that the CLOS metaobject protocol approach to defining and implementing an object model is very powerful. CLOS is an object-oriented language that is based on Common Lisp and is in the process ...
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ISBN:
(纸本)9780897914116
This paper demonstrates that the CLOS metaobject protocol approach to defining and implementing an object model is very powerful. CLOS is an object-oriented language that is based on Common Lisp and is in the process of being standardized. Implementations of CLOS are themselves object-oriented with all major building blocks of the language being instances of system classes. A metaobject protocol provides a framework for CLOS implementations by specifying the hierarchy of these classes and the order and contents of the communication among their instances. This design has made CLOS both flexible and portable, two design goals that traditionally conflict. In support of this suggestion we present a detailed account of how we added object persistence to CLOS without modifying any of the language's implementation code.
This paper shows that inheritance and subtyping can be introduced advantrgeously into a parallel object-oriented language, POOL-I. These concepts are clearly distinguished, because they deal with different aspects of ...
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Software components developed with an object-oriented language require frequent reorganizations before they become stable, reusable classes. We propose a new algoritlun that analyses the redefinitions carried out on i...
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In this paper we investigate the addition of first-class relationships to a prototypical object-orientedprogramming language (a "middleweight" fragment of Java). We provide language-level constructs to decl...
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ISBN:
(纸本)354027992X
In this paper we investigate the addition of first-class relationships to a prototypical object-orientedprogramming language (a "middleweight" fragment of Java). We provide language-level constructs to declare relationships between classes and to manipulate relationship instances. We allow relationships to have attributes and provide a novel notion of relationship inheritance. We formalize our language giving both the type system and operational semantics and prove certain key safety properties.
The ecoop workshop on Mobile object Systems was first organized in 1995 and has been held every year since. The first two episodes in the series - entitled “objects and Agents” (1995) and “Agents on the Move” (199...
ISBN:
(纸本)3540415130
The ecoop workshop on Mobile object Systems was first organized in 1995 and has been held every year since. The first two episodes in the series - entitled “objects and Agents” (1995) and “Agents on the Move” (1996) - were exploratory in nature, reflecting a growing awareness and interest in the possibilities of mobile code and mobile objects for Internet programming. Towards the end of the 1990s, Interest in the domain began to stabilize and several mobile object systems appeared in the research community. As a consequence, further editions of the Mobile object Systems workshop concentrated on specific aspects of mobile objects. Thus, the title of the 1997 workshop was “Operating System Support”, the theme of the 1998 workshop was “Security”, and the theme of the 1999 installment was “programming Language Support”.
This paper addresses the issue of schema evolution in LISPO2, a persistent object-oriented language. It introduces the schema modifications supported by the LISPO2 programming environment and presents the potential in...
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Genericity allows the substitution of types in a class. This is usually obtained through parameterized classes, although they are inflexible since any class can be inherited but is not in itself parameterized. We sugg...
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