K. Lieberherr, I. Holland, and A. Riel. Object-Oriented Programming: An Objective Sense of Style. In Proceedings of the Conference on Object-Oriented Systems, Languages and Applications (OOPSLA), San Diego, California, USA, pages 38--48, September 1988.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....system. Their style is claimed to increase information hiding, minimize coupling between classes, and improve maintainability and comprehensibility. They have developed tools to check if programs conform to the law. There are some shortcomings to the Demeter approach. The Demeter researchers [72] note that restructuring a program to make it conform with their law can require increasing the number of methods and method arguments, and result in slower execution speed and poorer readability of code. Wirfs Brock and Wilkerson [125] argue that the law overconstrains the con nections between ....

Karl J. Lieberherr, Ian M. Holland, and A. Rid. Object-oriented programming: An objective sense of style. In Proceedings of OOPSLA '88, pages 323 334, September 1988.

.... functions) that all classes should offer [RC90] and Packstone has suggested a set of guidelines for properly implementing overloaded operators [Pac90] Lieberherr and his colleagues have proposed the Law of Demeter , a language independent rule for achieving good style in object oriented programs [LHR88, LH89]. This law, which in C imposes constraints on the behavior of member functions, is formal enough to be checked by a program (as noted by its developers) Our work has some interesting relationships to this law, such as the fact that a violation of our error 6a allows a calling function to ....

K. Lieberherr, I Holland, and A. Riel. Object-Oriented Programming: An Objective Sense of Style. In Norman Meyrowitz, editor, Proceedings of the 1988 Conference on Object-Oriented Programming Systems, Languages and Applications (OOPSLA '88), pages 323--334. ACM Press, 1988. Published as ACM SIGPLAN Notices 23:1, November 1988.

....other objects. The use of global variables is often discouraged, on the grounds that they limit the reusability of the operations that access them. Some objectoriented design philosophies do not even allow an object b to interact with another object b 0 unless b has a direct reference to b 0 [LHR88] One consequence of this philosophy is that references to a particular object b tend to be duplicated throughout a system, with each object that uses b having a copy of its reference. This makes aliasing more common than it would be in systems which use a single global variable to contain b. To ....

K. Lieberherr, I. Holland, and A. Riel. Object oriented programming: An objective sense of style. SIGPLAN Notices, 23(11):323--334, February 1988. Proceedings of OOPSLA '88. Ref. on page 128.

....object model [Lie89] The effect is to prevent a method from being executed through more than one link (e.g. this.a.b.c.d. foo( They note, however, that the law can require an increase in the number of methods and method arguments resulting in poor code readability and slower execution speeds [Lie88]. In general, rules provided a checklist of things to look for and things to avoid but offered limited assistance in solving any particular object oriented design problem. A new approach to the transfer of object oriented design experience was presented in 1992 when Gamma released a preliminary ....

K. Lieberherr, I. M. Holland, and A. Riel. Object-oriented programming: An objective sense of style. In Proceedings OOPSLA '88, September 1988.

....We did not gather data metrics for C K s Response For a Class (RFC) and Lack of Cohesion in Methods (LCOM) The reason is due to our unability to measure them but also to the controversy about the way of measuring them. Item 23: Finally we counted the number of violations with the Law of Demeter [13, 12]. It is very embarrassing to find that the new version violates the law more than the old version. Because the law is generally accepted as a good OO programming style, we were disappointed when we found that our empirical results somewhat contradict the law. Writing programs that follow the law ....

K. Lieberherr, I. Holland, and A. Riel. Object-Oriented Programming: An Objective Sense of Style. In Proceedings of OOPSLA'88, pages 323--334, 1988.

....only. This style is claimed to increase information hiding, minimize coupling between classes, and improve maintainability and comprehensibility. They have developed tools to check if programs conform to the law. There are some shortcomings to the Demeter approach. The Demeter researchers [72] note that restructuring a program to make it conform with their law can require increasing the number of methods and method arguments, and result in slower execution speed and poorer readability of code. Wirfs Brock and Wilkerson [125] argue that the law overconstrains the connections between ....

Karl J. Lieberherr, Ian M. Holland, and A. Riel. Object-oriented programming: An objective sense of style. In Proceedings of OOPSLA `88, pages 323--334, September 1988.

....and quality control of software. Additionally work on software metrics has centered around the functional or process oriented view of software and fails to account for the inherently different paradigm of object orientation. Proposals to remedy this shortcoming have been studied by Lieberherr [KL88] CHAPTER 2. RELATED WORK 26 and Pfleeger [PP90] but the first effort to develop a set of theoretically driven set of metrics was undertaken by Chidamber [CK91] Based on the view of a design as a relational system, the authors suggested a metrics suite consisting of the following metrics: ffl ....

et. al. K. Lieberherr. Object Oriented Programming: An Objective Sense of Style. In Proceedings of Third Annual ACM Conf. on Object Oriented Programming Languages, Systems and Applications, 1988.

....they should exchange as little information as possible [2, 26] Fourth, long chains of messages should be avoided [21] Thus errors are easier to find and correct when the system is executed. Fifth, the Law of Demeter restricts the number of objects to which an object can send a message [23, 33]. Methods of the object are derived on the basis of the messages that the object receives. 8 The term cohesion is used to describe how well individual tasks are unified within a method. Higher cohesion leads to the easier maintenance of the system and to the greater reusability of the objects ....

K. Lieberherr, I. Holland, A. Riel, Object-Oriented Programming: An Objective Sense of Style, OOPSLA'88 Conference Proceedings, ACM Sigplan Notices, Vol. 23, No. 11, Nov 1988.

....problem described in Chapter 2.4 for transformation scope sub call. Similar solutions to those in scope sub call can be 1 A variation of this example and the ones following were suggested in the context of describing transformations that can be used to assure a program obeys the Law of Demeter [Lieberherr et al. 88] 149 used, such as using the output type or the usage of the initially selected expression (0.5) to narrow the possibilities. These would work for the example above, but since the algorithm is a heuristic, final approval of the tool s choice by the engineer is necessary. The result, after the ....

K. Lieberherr, I. Holland, and A. Riel. Object-oriented programming: an objective sense of style. In Proceedings of the Conference on Object Oriented Programming Systems, Languages and Applications, pages 323--334, November 1988. SIGPLAN Notices 23(11).

....we will define some axiomatic properties which have to be satisfied by any psychological complexity measure. PC is then validated against these properties. Object Oriented Features Object oriented designs have certain features that have been found to reduce the complexity of the software [21] [14]. Below we list the features and explain the role of the measure in those situations. 1. Inheritance: Whenever a class has to be developed we may have a choice of inheriting from an existing class or creating one from scratch. The measure will always favor inheritance to recreation indicating that ....

K. Lieberherr, I. Holland, and A. Riel. Object-oriented programming: A objective sense of style. In OOPSLA, pages 323--334, 1988.

.... of not strictly adhering to this rule by means of a concrete coupling metric taken from [8] Coupling is one of the most famous internal product attributes, studied since the advent of structured programming [18] 22] 26] and more recently, in the context of object orientation [3] 13] 14][16][24] Under the object oriented paradigm, the notion of coupling differs somewhat from the classical one, but the main ideas remain the same. In [8] Coupling Between Object Classes (CBO) is defined as a count of the number of other classes to which it is coupled . This definition implies that ....

....classes constitutes stronger coupling than access to instance variables of superclasess (the same holds, mutatis mutandis, for message passing) Passing a message with a wide parameter interface yields stronger coupling than passing one with a slim interface. Violating the Law of Demeter [16][17] yields stronger coupling than restricted (Demeter conforming) message passing 3 . Couples to the following types of objects should yield increasing coupling values: local objects, method parameters, subobjects of self ( instance variables of class type) subobjects of a super class 2 ....

[Article contains additional citation context not shown here]

K. Lieberherr, I. Holland, and A. Riel, "Object-Oriented Programming: An Objective Sense of Style", in Proc. OOPSLA '88, ACM 1988, pp. 323-334.

....of suitability is in part a complex and creative act. It requires a good knowledge of design patterns. Furthermore, the learning and usage of design patterns requires a fair knowledge about objectoriented modelling techniques and rules for good object oriented design as described in [John88] [Lieb88] [Lieb89] In order to reduce the complexity of the reorganization task, sometimes parts of the application were reorganized according to general design rules, before the design pattern was applied. The design of important abstractions in the application domain (links, documents) often requires ....

Karl J. Lieberherr, Ian M. Holland, and Arthur Riel. Object-oriented programming: An objective sense of style. In Proceedings OOPSLA '88, pages 323--334, November 1988. Published as ACM SIGPLAN Notices, volume 23, number 11.

....of foreign classes constitutes stronger coupling than access to instance variables of superclasses (a similar argument holds for message passing) Passing a message with a wide parameter interface yields stronger coupling than passing one with a slim interface. Violating the Law of Demeter [12][13] yields stronger coupling than restricted (Demeter conforming) message passing. Couples to the following types of objects should yield increasing coupling values: local objects, method parameters, subobjects of self ( instance variables of class type) subobjects of a super class ( ....

K. Lieberherr, I. Holland, Arthur Riel. Object-Oriented Programming: An Objective Sense of Style. In Proc. OOPSLA '88, ACM 1988, 323-334.

....scopes, the program fails with an error message. 5 Towards a Dee Style Any programming language encourages some styles of programming and discourages others. Dee is no exception. As an object oriented language, Dee supports an object oriented style of programming which has been widely discussed [33, 34]. In this section, we discuss some aspects of object oriented programming which have received little attention. The traditional approach to software development recommends interleaved refinement of control and data structures. Dee, perhaps to an even greater extent than other object oriented ....

K. Lieberherr, I. Holland, and A. Riel. Object-oriented programming: an objective sense of style. In N. Meyrowitz, editor, Proc. ACM Conf. on Object-Oriented Programming Systems, Languages and Applications, pages 323--334. ACM, 1988.

....the law of Demeter. As an illustration, consider the following code fragment which is a translation of the C code fragment in page 15 of [5] into Eiffel: class BOOK feature . end; class Book class MICROFICHEFILES feature 1 Different formulations, with minor differences can be found in [6, 4, 5]. This particular version, obtained from Karl Lieberherr by private communication, is the most recent formulation. search(book: BOOK) BOOLEAN is . end; end; class MicroFicheFiles class DOCUMENTS feature search(book: BOOK) BOOLEAN is . end; end; class Documents class ARCHIVE ....

....if c1 is closely related to c, a fact that can be determined by examining the class c itself. Therefore, adapting to such changes becomes easier. Similarly, if the composition of c1 changes (however the public interface stays invariant) LoD ensures that only c1 and its children are affected. In [6], 4] 5] these and other benefits of LoD are discussed in great detail. LoD helps in systematizing reuse as well: when class c is being reused in a different context only this small subset of closely related classes are needed to be brought in. Then for each class in this subset one can ....

K. Lieberherr, I. Holland, and A. Riel. Object oriented programming an objective sense of style. SIGPLAN NOTICES :special issue on OOPSLA 88, 23(11):323--334, November 1988.

....the issue of eliminating certain kinds of unwanted dependencies among classes, and between methods and the objects (variables and parameters) they manipulate. It can be implemented as a utility that checks programs for violations of the law and converts the offending sources to a legal form [13]. Algorithms have been developed to produce optimal inheritance graphs without attribute redundancy and with the minimum number of classes and inheritance links from pre existing hierarchies. These techniques are based on formal models of inheritance; they work globally, recasting an ....

K. Lieberherr, I. Holland and A. Riel, "Object-Oriented Programming: an Objective Sense of Style," SIGPLAN Notices (special issue on OOPSLA '88), vol. 23, no. 11, pp. 323--334, ACM, November 1988.

....structure will be. The introduction of indices in the catalogue has been a tradeoff between comprehensibility a new concept has to be understood and efficiency. 5.2 Comparison with other Approaches . Law of Demeter Both approaches support abstract programming. The Law of Demeter (cf. [8]) allows for checking and transforming programs automatically so that they comply with the law. In general, this requires adding several levels of indirection leading to a loss of efficiency. In contrast to this, some of the principles of coherent design such as conceptual abstraction cannot be ....

Lieberherr, K., Holland, I., and Riel, A. Object-Oriented Programming: an Objective Sense of Style. SIGPLAN Notices (special issue on OOPSLA `88), Meyrowitz, N. (Ed.), 23 (11). ACM, November 1988, pp. 323-334.

....that do not conform to the Law of Demeter do not yield directly call graphs from which propagation directives can be abstracted. Consider the program fragment in Fig. 30(a) This fragment contains a nested method application, a violation of the Law of Demeter, which can be corrected as follows [40]. Let the type of the object returned by method m1 be C. Then the above fragment can be rewritten as in Fig. 30(b) By repeatedly applying (a) struct B m( void send . send send send this m1( m2( m3( mn( b) struct B m( void send send this m1( m2new( ....

Karl J. Lieberherr, Ian Holland, and Arthur J. Riel. Object-oriented programming: An objective sense of style. In OOPSLA Conference, Special Issue of SIGPLAN Notices, pages 323--334, San Diego, CA., September 1988.

.... programming not only does not provide a systematic approach to the problem but also introduces new problems in understanding programs as a whole, due to the proliferation of many small member functions [WMH93] typical to objects and encouraged by style guidelines for good programming [LHR88, LH89]. Another problem with object oriented languages is that functions are attached to classes, introducing an implicit commitment to maintain each function s code dependencies on its own class and on the classes to which the code refers. With class structures changing frequently, this maintenance ....

Karl J. Lieberherr, Ian Holland, and Arthur J. Riel. Object-oriented programming: An objective sense of style. Number 11, pages 323--334, San Diego, CA., September 1988. A short version of this paper appears in IEEE Computer, June 88, Open Channel section, pages 78-79.

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K. Lieberherr, I. Holland, and A. Riel. Object-Oriented Programming: An Objective Sense of Style. In Proceedings of the Conference on Object-Oriented Systems, Languages and Applications (OOPSLA), San Diego, California, USA, pages 38--48, September 1988.

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K. Lieberherr and I. Holland and A. Riel. Object-Oriented Programming: An Objective Sense of Style. In Proceedings of OOPSLA '88. 1988.

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Lieberherr K., Holland I., and Riel A., "Object-Oriented Programming: An Objective Sense of Style", In Proceedings of OOPSLA Conference, 1988.

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K. Lieberherr, I. Holland, and A. J. Riel, "Object-oriented programming: An objective sense of style.," Object-Oriented Programming Systems, Languages and Applications Conference, in Special Issue of SIGPLAN Notices, vol. 11, pp. 323-334, 1988.

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Karl J. Lieberherr, Ian Holland, and Arthur J. Riel. Object-oriented programming: An objective sense of style. In Object-Oriented Programming Systems, Languages and Applications Conference, in Special Issue of SIGPLAN Notices, number 11, pages 323--334, San Diego, CA., September 1988. A short version of this paper appears in IEEE Computer, June 88, Open Channel section, pages 78-79.

No context found.

K. Lieberherr, I. Holland, and A. Riel. Object-oriented programming: An objective sense of style. Proc. OOPSLA`88, pages 323--334, September 1988.

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