Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....and create classes to store them ( factorize common properties ) We propose an incremental algorithm which performs maximal factorization of properties defined on the classes, and offers a solution to the problem of property overloading. Different methods are proposed in existing systems [Cas92, LBSL91, LBSL90, Ber91] to solve that factorization problem. We extend them, firstly by approaching the question of overloading, secondly by producing a more simple polynomial algorithm, thirdly by producing results that can be theoretically characterized. Our frame of reference to describe the algorithm is Galois ....

K. J. Lieberherr, P. Bergstein, and I. Silva-Lepe. Abstraction of object-oriented data models. Proceedings of International Conference on Entity-Relationship, 1990.

....reorganization; firstly because there exists no criteria defining what is a good hierarchy independently of a context, and secondly, because the construction rules are often very empirical. A lot of different works describe algorithms for automatic class insertion or hierarchy reorganization [MS89, LBSL90, Ber91, LBSL91, Cas92, Run92, GM93, Cas94, DDHL94a, Cas95, DDHL95, Moo95, CL96, DDHL96, Moo96]. Many of them focus on the most tangible criteria used when organizing hierarchies: to point out common properties and create classes to store them (i.e. factor common properties ) Beyond that common criterion, there is room for multiple variations: global handling of a hierarchy or incremental ....

....the factorization of all instructions common to several methods[Moo96] Such factorizations are only based on syntactic criteria, they will produce numerous methods and classes, the semantics of which being certainly quite unclear. ffl Algorithms can be global or incremental. Global algorithms [MGG90, LBSL91, LBSL90, Cas91, Moo95, MC96, CL96] build in a single step the whole hierarchy from the binary relation Class Gamma P roperty Incremental algorithms insert a new class into an already existing hierarchy. Such a technique is proposed by [Cas92, MS89, Run92, DDHL94a, DDHL95, GMM95, DDHL96] Cas92] proposes an interesting ....

[Article contains additional citation context not shown here]

K. J. Lieberherr, P. Bergstein, and I. Silva-Lepe. Abstraction of object-oriented data models. Proceedings of International Conference on Entity-Relationship, pages 81--94, 1990.

....Sj93] about how persistent or transient types change during maintenance. Researchers studying maintenance of object oriented hierarchies, which are not necessarily persistent, cite modifying types in the hierarchy and reorganizing the hierarchy as frequently desirable activities [JO93, OJ93, LBSL91, OJ90, Cas90, MS92a] One can expect, however, that maintainers are reluctant to make radical changes to an object oriented hierarchy or any other persistent type or schema definitions if those changes make it difficult or impossible to access existing data. As a result, the maintainers may ....

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In H. Kangassalo, editor, Entity-Relationship Approach: The Core of Conceptual Modelling, pages 89--102. Elsevier Science Publishers B.V., 1991. Similar to Johnson and Opdyke work on refactoring.

....they are particularly useful for the understanding of the system. All of them are incorporated into the book: The Art of Growing Software: An object oriented CASE approach [Lie92] ffl [LX91b] Theoretical background of the Demeter system. ffl [HSX91] A light introduction into Demeter. ffl [LBSL90] Abstraction of optimal class dictionary graphs from object examples. ffl [LXSL91] Propagation Patterns. ffl [Lie91] Growth plans. ffl [LH89] LHR88] Law of Demeter. 1.3 Overview The reader is expected to have a basic theoretical background of the Demeter method. Section 2 discusses the ....

.... graph is extracted manually or objects are defined which are then abstracted by the learning tool into a class dictionary graph[LBSL91, BL91] The class dictionary graph is then checked whether it satisfies the axioms, and it is made inductive, if necessary [LX91a] Optimization [LBSL91, LBSL90] and normalization [Lie88] conclude the class dictionary graph transformations. The class dictionary graph is then extended into a class dictionary by adding terminals. The resulting class dictionary is checked for the LL(1) conditions [LX91b, Lie88] To debug the class dictionary, it is ....

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....they are particularly useful for the understanding of the system. All of them are incorporated into the book: The Art of Growing Software: An object oriented CASE approach [Lie92] ffl [LX91b] Theoretical background of the Demeter system. ffl [HSX91] A light introduction into Demeter. ffl [LBSL90] Abstraction of optimal class dictionary graphs from object examples. ffl [LXSL91] Propagation Patterns. ffl [Lie91] Growth plans. ffl [LH89] LHR88] Law of Demeter. 1.3 Copyright The Demeter System TM software is confidential and proprietary to Northeastern University. c fl 1992 ....

.... graph is extracted manually or objects are defined which are then abstracted by the learning tool into a class dictionary graph[LBSL91, BL91] The class dictionary graph is then checked whether it satisfies the axioms, and it is made inductive, if necessary [LX91a] Optimization [LBSL91, LBSL90] and normalization [Lie88] conclude the class dictionary graph transformations. The class dictionary graph is then extended into a class dictionary by adding terminals. The resulting class dictionary is checked for the LL(1) conditions [LX91b, Lie88] To debug the class dictionary, it is ....

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....types change during maintenance. Researchers studying maintenance of object oriented hierarchies, which are not necessarily persistent, cite modifying types in the hierarchy and reorganizing the hierarchy as frequently desirable activities [Johnson and Opdyke 1993; Opdyke and Johnson 1993; Lieberherr et al. 1991; Opdyke and Johnson 1990; Casais 1990; Mellor and Shlaer 1992] One can expect, however, that maintainers are reluctant to make radical changes to an object oriented hierarchy or any other persistent type or schema de nitions if those changes make it dicult or impossible to access existing data. ....

Lieberherr, K. J., Bergstein, P., and Silva-Lepe, I. 1991. Abstraction of object-oriented data models. In H. Kangassalo Ed., Entity-Relationship Approach: The Core of Conceptual Modelling , pp. 89-102. Elsevier Science Publishers B.V. Similar to Johnson and Opdyke work on refactoring.

....and create classes to store them ( factor common properties ) We propose an incremental algorithm which performs maximal factorizing of properties defined on the classes, and offers a first solution to the problem of property overloading. We extend different methods proposed in existing systems [Cas92, LBSL91, LBSL90, Ber91] to solve that factorizing problem. We approach property overloading, and produce a simple polynomial algorithm, whose results are well specified. To describe the algorithm, we use Galois lattices, already much used in other domains (e.g. machine learning, information retrieval, knowledge ....

K. J. Lieberherr, P. Bergstein, and I. Silva-Lepe. Abstraction of object-oriented data models. Proceedings of International Conference on Entity-Relationship, 1990.

....Name:string Pop:int LiesIn Name:string Length:real LiesAt FlowsThrough Fig. 2. Town Country River ER like the relation between Entity Relationship and Object Oriented modelling has always been in the center of interest on the Entity Relationship conferences (see for example [Dit87, NP88, KS88, LBSL90, RS91, ADD 92, PKB94, LT94] among many other interesting papers) 3 Interpretation of Database Schemas We now turn to the compelling question of how single elements of the given object domains are identified. But before going into details concerning this point, we have to clarify how we ....

K.J. Lieberherr, P. Bergstein, and I. Silva-Lepe. Abstraction of Object-Oriented Data Models. In H. Kangassalo, editor, Proc. 9th Int. Conf. on EntityRelationship Approach (ER'90), pages 81--94. ER Institute, Pittsburgh (CA), Participants' Proceedings, 1990.

No context found.

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....class dictionary graphs (section 3.2) present the details of the algorithm for abstracting class dictionary graphs from object examples (section 3.3) and elaborate on the minimization of class dictionary graphs (section 3.4) Sections 3.2 and 3. 3 are the result of joint work with Paul Bergstein [38, 37]. The definitions in these sections can also be found in [6] 3.2 Class dictionary graphs Class dictionary graphs, first introduced in [38] are a formal notation for describing class structures that is programming language independent. The class dictionary graph in Fig. 2 describes a class ....

....graph. This is formalized in the tree property concept by checking whether the sets of associated vertices of a class dictionary graph satisfy the tree property, we are effectively transforming such a class dictionary graph into a single The tree property was first introduced informally in [37]. inheritance class dictionary graph. A collection of subsets of a set S has the tree property if for any pair of subsets of S one element of the pair is completely contained in the other or the two subsets are disjoint. 2 It is not difficult to see that the tree property can be checked in ....

[Article contains additional citation context not shown here]

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of objectoriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....This paper reports on our teaching approach which we have used since 1986 to present object oriented programming and design both in academic and industrial environments. Our research is aimed at developing a programming language independent method for the study of objectoriented programming. 6. LBSL90] The contributions of this paper are two fold: First we introduce a novel, axiomatically defined objectoriented data model, called the Demeter kernel model, and second we outline several computational problems underlying the bottom up design process in the kernel model. Specifically, we sketch a ....

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier. 8

....continents. Graduate students have made significant contributions to the Demeter project, both to the code and to publications related to the system; the following papers were authored or co authored by graduate students: LR88a] LHR88] LR88b] LR89] LHR88] LH89a] LH89c] LH89b] LBSL90] Hol92] Ber91] BL91] LHSLX92] LBSL91] LX93a, LSLX92, LX93b, Kes93, LSLX93, SLHS94, SL93b, SL93a, BH93, HLM93, LHX93, LZHL94, LX93c] The following thesis has been completed: Hol93] 2 Bibliography ....

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of objectoriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

.... modify check optimize Figure 1: Use of class dictionary graphs are then abstracted by the learning tool into a class dictionary graph[LBSL91, BL91] The class dictionary graph is then checked whether it satisfies the axioms, and it is made inductive, if necessary [LX91a] Optimization [LBSL91, LBSL90] and normalization [Lie88] conclude the class dictionary graph transformations. The class dictionary graph is then extended into a class dictionary by adding terminals. The resulting class dictionary is checked for the LL(1) conditions [LX91b, Lie88] To debug the class dictionary, it is ....

....2: Use of class dictionaries [Lie88] LR88] LH89b] LR89] This paper contains the following new material with respect to our earlier papers on the Demeter system: 1. semi class dictionary graphs. 2. an axiomatic, graph theoretic foundation for class dictionaries (some earlier papers [LBSL91, LBSL90, LX91a] introduce class dictionary graphs only, while others introduce class dictionaries only informally [Lie88, LR89] 3. a formal description of the connection between class dictionaries and languages. 4. the LL(1) requirement are derived from a bijection condition between objects and ....

[Article contains additional citation context not shown here]

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of objectoriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....Brown for their contributions. An early version of this paper, using a different growth plan concept, was written jointly with Carl Woolf [LW89] The axioms for class dictionary and object graphs are key ingredients to other papers where we present results of the theory of class dictionary graphs [LBSL90, LBSL91, BL91, LX91]. This work is supported in part by IBM Yorktown and IBM Kingston, Mettler Toledo and the National Science Foundation under grants CCR 9102578 (Software Engineering) and CDA9015692 (Research Instrumentation) ....

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of objectoriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....syntax Figure 1: Software engineering using the Demeter Method of legal objects, including the identified ones, through relationships between classes. The class dictionary graph is then checked whether it satisfies the axioms, and it is made inductive, if necessary [LX93b] Optimization [LBSL91, LBSL90] and normalization [Lie88] conclude the class dictionary graph transformations. A class dictionary graph defines a class library which contains basic methods for manipulating the objects defined by the class dictionary graph. To allow for short descriptions of objects, class dictionary graphs ....

....of the class grammar connection in a sophisticated way [Lie88] LR88] LH89] LR89] This paper contains the following new material with respect to our earlier papers on the Demeter method: 1. an axiomatic, graph theoretic foundation for class dictionaries (some earlier papers [LBSL91, LBSL90, LX93b] introduce class dictionary graphs only, while others introduce class dictionaries only informally [Lie88, LR89] 2. a formal description of the connection between class dictionaries and languages. 3. the LL(1) conditions from language theory[ASU86] are generalized for class dictionaries. ....

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....in 1984 and continued at Northeastern since 1985. The pattern of our research is to identify abstractions in the object oriented software development process, to formalize the abstractions and to provide tools to take advantage of the abstractions [20] 26] 23] 22] 10] 25] 24] 27] [21], 14] Dozens of students have been involved in the research and in tool development. Hundreds of users in the U.S. and Europe have used our tools and have learned the theory on which the tools are based. The tools are part of the Demeter System which consists of the Method and supporting Tools. ....

....a vertex must be included in 23 A B C PA SA PC SC PB SB a c b Figure 17: An alternation cycle the partial class dictionary graph containing that vertex. Therefore the Inductiveness Axiom axiom is violated. Further results of the theory of class dictionary graphs are given in [22] [21], 4] 5] and [14] 4 Programming with class dictionary graphs We show with a simple example how we use class dictionary graphs to simplify programming. We have developed a CASE tool for C [34] the C Demeter System [26] which maps class dictionary graphs into a C class library. The C ....

[Article contains additional citation context not shown here]

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....a CASE tool for object oriented design and programming. Keywords: Object oriented programming and design, reverse engineering, formal software engineering techniques, class hierarchy optimization. Acknowledgements: Preliminary versions of this paper were published in the proceedings of ER 90 [LBSL90b] and SOOLS 90 [LBSL90a] 1 1 Introduction In their paper [JF88] Johnson and Foote state that useful abstractions are usually designed from the bottom up, i.e. they are discovered, not invented. In [Ste89] Steier presents a theory of human algorithm design. He compares this theory with ....

....algorithms. The automatically generated class definitions help to evaluate the class definitions in the existing programs. The algorithms are easy to teach and can be applied by hand. 3 However, when the result is a single inheritance hierarchy, the task can be solved in polynomial time [LBSL90b] 5 a1:Adm assistant course assigned ssn n1:Number Economics Comp Sci salary r1:Real p1:Professor ssn n1:Number salary r1:Real c1:Course major u1:Undergrad student ssn n1:Number gpa r1:Real e1:Economics course assigned t1:TA ssn n1:Number salary r1:Real c1:Course ....

[Article contains additional citation context not shown here]

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of objectoriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier. 51

....in 1984 and continued at Northeastern since 1985. The pattern of our research is to identify abstractions in the object oriented software development process, to formalize the abstractions and to provide tools to take advantage of the abstractions [21] 28] 25] 24] 12] 27] 26] 29] [22]. Dozens of students have been involved in the development of the Demeter System which consists of the Demeter Method and the Demeter Tools, a suite of CASE (Computer Aided Software Engineering) tools. The Method describes a technique for object oriented software engineering, based on the class ....

....might be violated. For example, if we choose in Fig. 10c the partial class dictionary graph anchored at List and containing Nonempty then we have a partial class dictionary graph which violates the Inductiveness Axiom. Further results of the theory of class dictionary graphs are given in [23] [22], 6] and [7] 3.3 Programming with class dictionary graphs To motivate the usefulness of class dictionary graphs further, we show with a simple example how we use them to simplify programming. We have developed a CASE tool for C [36] the Demeter Tools C [28] which map class dictionary ....

[Article contains additional citation context not shown here]

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....a class dictionary graph is abstracted out [LBSL91, BL91] A class dictionary graph defines a set of legal objects, including the identified ones. The class dictionary graph is then checked whether it satisfies the axioms, and it is made inductive, if necessary [LX93a] Optimization [LBSL91, LBSL90] and normalization [Lie88] conclude the class dictionary graph transformations. A class dictionary graph defines a class library which contains basic methods for manipulating the objects defined by the class dictionary graph. Requirements identify identify abstract Objects Class dictionary ....

....papers on the Deme 1 In this paper we use C as object oriented language. But the Demeter Method is applicable to any object oriented language, such as Smalltalk, Eiffel, or Oberon 2. ter method: 1. an axiomatic, graph theoretic foundation for class dictionaries (some earlier papers [LBSL91, LBSL90, LX93a] introduced class dictionary graphs only, while others introduced class dictionaries only informally [Lie88, LR89] 2. a formal description of the connection between class dictionaries and languages. 3. the LL(1) conditions from language theory [ASU86] are generalized for class ....

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of object-oriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....this requirement by allowing users to express concise (abbreviated) queries, so that they can manage with partial or even no knowledge of the database structure . In the world of objectoriented programming, database schemas have been proposed to have their counterpart in class dictionary graphs [LBS90]. In simplistic terms, class dictionary graphs describe concisely a collection of classes along with the part of and is a relations among the classes. Class dictionary graphs have the advantage of being programming language independent and are therefore useful to programmers who use ....

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of objectoriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Elsevier, Lausanne, Switzerland, 1990.

....a CASE tool for object oriented design and programming. Keywords: Object oriented programming and design, reverse engineering, formal software engineering techniques, class hierarchy optimization. Acknowledgements: Preliminary versions of this paper were published in the proceedings of ER 90 [LBSL90b] and SOOLS 90 [LBSL90a] 1 Introduction In their paper [JF88] Johnson and Foote state that useful abstractions are usually designed from the bottom up, i.e. they are discovered, not invented. In [Ste89] Steier presents a theory of human algorithm design. He compares this theory with ....

....algorithms. The automatically generated class definitions help to evaluate the class definitions in the existing programs. The algorithms are easy to teach and can be applied by hand. 3 However, when the result is a single inheritance hierarchy, the task can be solved in polynomial time [LBSL90b] a1:Adm assistant course assigned ssn n1:Number Economics Comp Sci salary r1:Real p1:Professor ssn n1:Number salary r1:Real c1:Course major u1:Undergrad student ssn n1:Number gpa r1:Real e1:Economics course assigned t1:TA ssn n1:Number salary r1:Real c1:Course r2:Real gpa major ....

[Article contains additional citation context not shown here]

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of objectoriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

....the class definitions are a non trivial abstraction of the objects. We claim it is easier to initially describe certain example objects and to get a proposal for an optimal set of class definitions generated automatically than to write the class definitions by hand. We have previously shown ( LBSL90] LBSL91] how the discovery of classes from objects can be automated, and how the resulting class organization can be efficiently optimized in the case where the optimum is a single inheritance class hierarchy. This paper extends our previous work in an important way: We show how an optimal ....

....than to proceed manually from the object examples. For further information on our research program in object oriented software engineering, we refer the reader to the survey in [WBJ90] In section 2 the basic learning algorithm is formally presented. An informal presentation has been given in [LBSL90] This algorithm learns a correct (but not optimal) class dictionary graph from a list of object example graphs. An algorithm for learning class dictionary graphs incrementally is given in section 3. The ability to expand a class dictionary incrementally as new object examples are presented is an ....

[Article contains additional citation context not shown here]

Karl J. Lieberherr, Paul Bergstein, and Ignacio Silva-Lepe. Abstraction of objectoriented data models. In Hannu Kangassalo, editor, Proceedings of International Conference on Entity-Relationship, pages 81--94, Lausanne, Switzerland, 1990. Elsevier.

No context found.

K.J. Lieberherr, P. Bergstein, and I. Silva-Lepe. Abstraction of ObjectOriented Data Models. In H. Kangassalo, editor, Proc. 9th Int. Conf. on Entity-Relationship Approach (ER'90), pages 81--94. ER Institute, Pittsburgh (CA), Participants' Proceedings, 1990.

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