H. Okamura, Y. Ishikawa, and M. Tokoro. Al-1/d: A distributed programming system with multi-model reflection framework. In A. Yonezawa and B. Smith, editors, Proceedings of the International Workshop on New Models for Software Architectures, Reflection and Metalevel Architectures, pages 36--47. RISE (Japan), ACM Sigplan, JSSST, IPSJ, November 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....In practice, existing partial evaluation techniques do not allow us to directly deal with the meta circular interpreters written in concurrent object oriented languages. Here we explain the underlying problems and our proposed solutions. Concurrent meta system. As the previous studies show[76, 94, 125], it is natural to design the meta system of a concurrent object oriented language with concurrent objects. However, it is difficult to eliminate the meta level interpretation by partially evaluating the entire meta system, because of the concurrency and indeterminacy of concurrent objects. To the ....

....if the number of dynamic branches in a meta object increases. In fact, it does in practical reflective languages; the full meta object in ABCL R has the waiting state in addition to dormant and active ; and the meta object in AL 1 D has 6 states (dormant, ready, run, waiting, migrating, and stop)[94]. 90 ffl Information that should be known (static) to the partial evaluator is transferred via instance variables between consecutive method invocations. Such information is not available on the receiver s side unless data structures are analyzed extensively. For example, the value of (get ....

Hideaki Okamura, Yutaka Ishikawa, and Mario Tokoro. AL-1/D: Distributed programming system with multi-model reflection framework. In Yonezawa and Smith [131], pp. 36--47.

....layers in the reflective hierarchy can be quite complex. The challenge here is to develop easy to use principles for harnessing the power of reflection and avoiding the potential chaos that is possible with its unrestricted use. In other reflective models for distributed object computation [7, 2, 1], an object is represented by multiple models allowing behavior to be described at different levels of abstraction and from different points of view. In each model the behavior of an object is described by a metaspace that consists of meta objects representing the different models aspects (e.g. ....

H. Okamura, Y. Ishikawa, and M. Tokoro. Al-1/d: A distributed programming system with multi-model reflection framework. In A. Yonezawa and B. C. Smith, editors, Reflection and Meta-Level Architetures, pages 36--47. ACM SIGPLAN, 1992.

....principles. We explore the relationship between MIM and reflection in the context of the OpenORB reflective middleware architecture. The main principle underlying this architecture is the use of a multi model reflection framework, which was first advocated by the creators of the AL 1 D language [3]. It consists in applying separation of concerns to the design of the meta level itself, whereby the distinct aspects of an entity s metaspace are dealt with separately by independent metamodels. In this way, we expect to minimise the complexity of meta level programming for middleware as ....

H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proceedings of International Workshop on New Models for Software Architecture (IMSA'92), Tokyo, Japan, November 1992.

....We explore the relationship between MIM and reflection in the context of our architecture for reflective middleware, the OpenORB. The main principle underlying the architecture is the use of a multi model reflection framework, which was first advocated by the creators of the AL 1 D language [OIT92]. It consists in applying separation of concerns in the metalevel, whereby the distinct aspects of an en tity s meta space are dealt with separately by independent and orthogonal meta entities. In this way, we expect to minimise the complexity of meta level programming for middleware since each ....

H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proceedings of Workshop on New Models for Software Architecture, November 1992. (Also available from the Department of Computer Science, Keio University, Japan).

....by the great complexity involved in a meta level for middleware. By modelling (and implementing) each aspect as an independent meta model, both the meta level design and the use of reflective computation are made simpler. The concept of multi model reflection was first introduced in AL 1 D [19], which defines a set of meta models to deal with the different aspects normally found in distributed systems. AL 1 D, however, does not stress the importance of orthogonality between the meta models, which greatly improves their manageability. Currently, in our architecture, we have identified ....

H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proceedings of Workshop on New Models for Software Architecture, November 1992. (Also available from the Department of Computer Science, Keio University, Japan).

....by the great complexity involved in a meta level for middleware. By modelling (and implementing) each aspect as an independent meta model, both the meta level design and the use of reflective computation are made simpler. The concept of multi model reflection was first introduced in AL 1 D [21], which defines a set of meta models to deal with the different aspects normally found in distributed systems. AL 1 D, however, does not stress the importance of orthogonality between the meta models, a feature which greatly improves their manageability. Currently, in our architecture, we have ....

H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proceedings of International Workshop on New Models for Software Architecture (IMSA'92), Tokyo, Japan, November 1992.

....the programmer can program object location control facilities more flexibly than that in existing DPLs which do not support capabilities for obtaining such information. The location control mechanisms discussed in this paper have been implemented on our AL 1 D reflective programming system [13]. Based on the evaluation of application programs in AL 1 D, we discuss the trade off between the overhead incurred by meta level programming and performance improvement gained by object location control. Section 2 discusses several useful object location control facilities which are necessary in ....

....4 Meta Level Programming in AL 1 D In this section, we cover the object location control facilities by meta level programming provided by the AL 1 D distributed reflective system. AL 1 D is a concurrent object based reflective programming system that may be used over distributed environments [13]. An AL 1 D system consists of a compiler and a virtual machine, that is, a bytecode interpreter, constructed on a UNIX based operating system. Basically, programs are constructed using concurrent objects and messages. The message sending syntax is similar to that of ConcurrentSmalltalk [20] ....

Hideaki Okamura, Yutaka Ishikawa and Mario Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proceedings of the International Workshop on New Models for Software Architecture'92 Reflection and Meta-level Architecture, November 1992.

....(as the implementation itself is directly manipulated) 6] The final principle is to structure meta space as a number of closely related but distinct meta space models. This approach was first advocated by the designers of AL 1 D, a reflective programming language for distributed applications [7]. The benefit of this approach is to simplify the interface offered by meta space by maintaining a separation of concerns between different system aspects. The three aspects currently employed are: composition, encapsulation and environment. This is however not a closed list and the range of ....

....by a number of specific reflective languages. As stated above, the concept of multi models was derived from AL 1 D. The underlying models of AL 1 D are however quite different; the language supports six models, namely operation, resource, statistics, migration, distributed environment and system [7]. Our ongoing research on the environment and encapsulation meta models is also heavily influenced by the designs of ABCL R [3] and CodA [8] Both these systems feature decompositions of meta space in terms of the acceptance of messages, placing the message in a queue, their selection, and the ....

H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/d: A distributed programming system with multi-model reflection framework. In Proceedings of Workshop on New Models for Software Architecture, November 1992. (Also available from the Department of Computer Science, Keio University, Japan).

....the programmer can program object location control facilities more flexibly than that in existing DPLs which do not support capabilities for obtaining such information. The location control mechanisms discussed in this paper have been implemented on our AL 1 D reflective programming system [13]. Based on the evaluation of application programs in AL 1 D, we discuss the trade off between the overhead incurred by meta level programming and performance improvement gained by object location control. Section 2 discusses several useful object location control facilities which are necessary in ....

....4 Meta Level Programming in AL 1 D In this section, we cover the object location control facilities by meta level programming provided by the AL1 D distributed reflective system. AL 1 D is a concurrent object based reflective programming system that may be used over distributed environments [13]. An AL 1 D system consists of a compiler and a virtual machine, that is, a bytecode interpreter, constructed on a UNIX based operating system. Basically, programs are constructed using concurrent objects and messages. The message sending syntax is similar to that of ConcurrentSmalltalk [20] ....

Hideaki Okamura, Yutaka Ishikawa, and Mario Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proceedings of the International Workshop on New Models for Software Architecture'92 Reflection and Metalevel Architecture, November 1992.

....a message to its target. Other examples of adaptative policies could be the implementation of a memory management suitable for the object granularity [YMFT91] Some other examples of MOPs providing a set of control metaobjects at the metalevel are Muse, CodA [McA95] Iguana [GC96] AL 1 D [OIT92] Actalk and so on. Note that some of them also provide structural reflection oriented metaobjects that can be used to process a certain kind of introspection especially in Iguana. One of the most simple example of behavioral reflective architecture is the OpenC v1 MOP [Chi93] Most of these ....

H. Okamura, Y. Ishikawa, and M. Tokoro. Al-1/d: A distributed programming system with multi-model reflection framework. In Proceedings of the International Workshop on New Model of Software Architecture'92 Reflection and Meta-level Architecture, November 1992.

....must effectively allow them to step into the implementation of method invocation, to detect whether it is local or remote, and to implement the appropriate amount of copying in each case. One way to do this is to provide runtime reflective access to method invocation. As has been shown in [7, 23, 35, 37] such reflective access can be used to control the communication aspect of a distributed object system. But this kind of reflective access is so powerful that it can be dangerous or difficult to use. So in this case we have chosen to provide a higher level aspect language, that is more tailored to ....

Okamura H., Ishikawa Y., et al., Al-1/d: A distributed programming system with multi-model reflection framework, in proc. International Workshop on New Models for Software Architecture '92; Reflection and MetaLevel Architecture, pp. 36--47, 1992.

.... explore the relationship between MIM and reflection in the context of our architecture for reflective middleware, the OpenORB [BCC 99] The main principle underlying the architecture is the use of a multi model reflection framework, which was first advocated by the creators of the AL 1 D language [OIT92]. It consists in applying separation of concerns in the meta level, whereby the distinct aspects of an entity s meta space are dealt with separately by independent and orthogonal metaentities. In this way, we expect to minimise the complexity of meta level programming for middleware since each ....

H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proceedings of Workshop on New Models for Software Architecture, November 1992. (Also available from the Department of Computer Science, Keio University, Japan).

....reasoning about heterogeneous systems. Meta actors communicate with each other via message passing as do base level actors, but they may also examine and modify the state of the base actors located on the same node. The multi model reflective framework for distributed object computation (MMRF) [23] has many of the same motivations and objectives as the TLAM framework. We briefly compare the two approaches. In MMRF an object is represented by multiple models allowing behavior to be described at different levels of abstraction. In each model the behavior of an object is described by a meta ....

H. Okamura, Y. Ishikawa, and M. Tokoro. Al-1/d: A distributed programming system with multi-model reflection framework. In A. Yonezawa and B. C. Smith, editors, Reflection and Meta-Level Architetures, pages 36--47. ACM SIGPLAN, 1992.

....and on metalogical foundations for reflection [56] will be extended in several ways. More generally, we will take into account many previous contributions by other researchers in the area of software architecture and module composition operations [6, 67, 15, 19, 8, 41, 36, 28, 75] in reflection [71, 70, 79, 76, 41, 38, 81, 7, 68, 39, 12, 53, 24, 37, 52, 61, 64, 69], and in recent approaches to interoperation [34, 13, 14, 42, 5, 1, 45, 20] The proposed research will lead to a new technology for composition, interoperation, and dynamic evolution of software systems. It will treat interoperability at many levels and along many dimensions components, ....

....and for building systems that are truly adaptable and survivable. Many researchers have recognized the great importance and usefulness of reflection in programming languages [71, 70, 79, 76, 41, 38] in theorem proving [81, 7, 68, 39, 12, 53, 24, 37] in concurrent and distributed computation [52, 61, 64], and in many other areas such as compilation, programming environments, operating systems, fault tolerance, and databases (see [69] for a recent snapshot of research in reflection) The importance of reflection for software engineering is linked to the increasing importance of building ....

Hideaki Okamura, Yutaka Ishikawa, and Mario Tokoro. AL-1/D: A distributed programming system with multi-model reflection framework. In IMSA'92, pages 36--47. InformationTechnology Promotion Agency, Japan, 1992.

....and mechanisms for maintaining consistency and allowing them to work together and to interact with the environment. In a computational setting, the idea of dual interfaces [40] is an example of a binary organization. The multi model reflective framework for distributed object computation (MMRF) [60] 5 is another example. A reflective architecture for coordination in open distributed systems is described in [1] Here, meta level coordinators are coupled to application level components statically via interface operations and dynamically via events. The two level actor model [78] is a first ....

H. Okamura, Y. Ishikawa, and M. Tokoro. Al-1/d: A distributed programming system with multi-model reflection framework. In A. Yonezawa and B. C. Smith, editors, Reflection and Meta-Level Architetures, pages 36--47. ACM SIGPLAN, 1992.

....methods (the behaviors of the base level s programs) Dynamically adaptable software in LEAD has reflectivity like this. 4 Related Works There are several works on the linguistic approach for dynamically adaptable software: Rome[2] Clovers[7] Compositional adaptation[3] Gaea[5] AL 1 D[6], etc. Our software model and its languages (LEAD, LEAD ) have the following advantages. 1) Since it is independent of the specific description languages, it can be applied various kinds of languages and their software easily. 2) We can improve the dynamic adaptability of adaptable procedures by ....

H. Okamura, Y. Ishikawa, and M. Tokoro. Al1 /d: A distributed programming system with multimodel reflection framework. In Proceedings of the IMSA'92 International Workshop on Reflection and Meta-level Architecture, November 1992.

....ones a little. The current developing platform is WindowsNT 95. We had already developed the class libraries and several low level library functions. 4 Related Works There are several works on the linguistic approach for DAS: Rome [2] Clovers [10] Compositional Adaptation [4] Gaea [8] AL 1 D [9], etc. Then, as object oriented reflective languages, there are also CLOS [5] Open C [3] etc. Our model and the language LEAD have the following features toward those works. 1) We can realize dynamic adaptability based on procedures in application programs. Thus, we can apply our model to ....

H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proc. of IMSA'92, 1992.

....Software in LEAD Base Level Meta Level Metalevel Architecture Fig. 2. Dynamically adaptable software in LEAD . IV. RELATED WORKS There are several works on the linguistic approach for dynamically adaptable software: Rome[2] Clovers[8] Compositional Adaptation[3] Gaea[6] AL 1 D[7], etc. Toward these related works, our software model and its languages LEAD have the following advantages. ffl Since our model is independent of the specific description languages, we can apply it to various kinds of languages and their software easily. ffl We can improve the dynamic ....

H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proceedings of the IMSA'92 International Workshop on Reflection and Meta-level Architecture, November 1992.

....multiple models. ffl A model consists of system components at one or more abstraction levels and user s views. ffl Decomposed models can run concurrently to, and independently of other models. ffl Consistency checking are supported to enable consistent execution. One of our previous papers [OIT92] concentrated on the programming style in the AL1 D system. That is, we presented some useful models on AL 1 D and described how to modify the system with those models. The definition of MMRF, however, was ambiguous. This paper describes the definition of MMRF, what structure of decomposed models ....

....the strategy of the migration mechanism. In the following, we explain how basic models are represented, and what can be modified in basic models. This paper describes the Operation and Resource models, using sample programs. Other models are over viewed. The use of these models is described in [OIT92]. normal satisfier solving satisfy not satisfy done check transition 1 stop ready dormant waiting rep received req sent bind cond self super reply stop invoke terminate terminate activate invoke invoke beginMigrate endMigrate beginMigrate endMigrate beginMigrate ....

Hideaki Okamura, Yutaka Ishikawa, and Mario Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Proceedings of the International Workshop on New Models for Software Architecture'92 Reflection and Meta-level Architecture, November 1992.

No context found.

H. Okamura, Y. Ishikawa, and M. Tokoro. Al-1/d: A distributed programming system with multi-model reflection framework. In A. Yonezawa and B. Smith, editors, Proceedings of the International Workshop on New Models for Software Architectures, Reflection and Metalevel Architectures, pages 36--47. RISE (Japan), ACM Sigplan, JSSST, IPSJ, November 1992.

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H. Okamura, Y. Ishikawa, and M. Tokoro, \AL-1/D: A distributed programming system with multi-model re ection framework," in Proceedings of the Workshop on New Models for Software Architecture, Nov. 1992.

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H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Workshop on New Models for Software Architecture, November 1992.

No context found.

Hideaki Okamura, Yutaka Ishikawa, and Mario Tokoro. AL-1/D: A distributed programming system with multi-model reflection framework. In IMSA'92, pages 36--47. Information-Technology Promotion Agency, Japan, 1992.

No context found.

H. Okamura, Y. Ishikawa, and M. Tokoro. AL-1/D: A Distributed Programming System with Multi-Model Reflection Framework. In Workshop on New Models for Software Architecture, November 1992.

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Okamura, H., Y. Ishikawa, and M. Tokoro. Al-1/d: A distributed programming system with multi-model reflection framework. in International Workshop on New Models for Software Architecture '92; Reflection and Meta-Level Architecture. 1992.

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