Khoshafian, S., & Copeland, G. (1986). Object identity. In Proceedings of the OOPSLA '86 Conference (pp. 406--416). New York: ACM Press.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....P 2 : direct pointer to D P 1 : indirect pointer to D 28 3.2.1 Object Identification and Squids Forwarding pointer aliasing is an instance of the more general challenge of determining object identity in the presence of multiple and or changing names. This problem has been studied explicitly [Setrag86]. A natural solution which has appeared time and again is the use of systemwide unique object ID s (e.g. Dally85] Setrag86] Moss983 [Day98 [Plainfoss9976 UID s completely solve the aliasing problem, but have two disadvantages: i. The use of ID s to reference objects requires an expensive ....

....is an instance of the more general challenge of determining object identity in the presence of multiple and or changing names. This problem has been studied explicitly [Setrag86] A natural solution which has appeared time and again is the use of systemwide unique object ID s (e.g. Dally85] [Setrag86], Moss983 [Day98 [Plainfoss9976 UID s completely solve the aliasing problem, but have two disadvantages: i. The use of ID s to reference objects requires an expensive translation each time an object is referenced to obtain its virtual address. ii. Quite a few bits are required to ensure that ....

Setrag N. Khoshafian, George P. Copeland, "Object Identity", Proc. 1986 ACM Conference on Object Oriented Programming Systems, Languages and Applications, pp. 406416.

....with Smalltalk experience papers, and actor message passing architectures. Lewi86 Patt83 Samp86 Snyd79 Unga84] Concepts: There are an increasing number of papers discussing various object oriented concepts. See also survey papers and special issues, and papers on types and on data abstraction, [Borg86 Cunn86 Gogu86 Hend86 Khos86 Lalo86 Lieb86 Mads86 Nguy86 Ossh86 Sand86 Snyd86b Stro86c Wegn86] Concurrency: These papers discuss various mechanisms and formalisms for coping with concurrency (CSP, monitors, etc. The Andrews survey is excellent. Andr81 Andr83 Bern81 Brin72 Brin73 Brin78 Broo84 Dijk75 Hoar74 Hoar78 Lamp83 Nier87b Shoc82 Silb84 Upfa84] Data Abstraction: These papers ....

S.N. Khoshafian and G.P. Copeland, "Object Identity", ACM SIGPLAN Notices, vol. 21, no. 11, pp. 406-416, Nov 1986.

....add 3 . m: x o: y z) I) o: m: x y) m: x z) as an axiom to pecDy. p then assigns the same effect to these otherwise different processes. 7.2 Active objects In our approach, the concept of a globally unique identifier for each actor is crucial. Identifiers are also crucial for objects [3, 27], so we could try to unify the concepts of actor and object in that of an active object. Elswhere [45, 47] it is argued that in an algebraic specification framework, the only essential addition to be made to get an object oriented specification language is the idea of localization of properties ....

S.N. Khoshafian and G.P. Copeland. Object identity. In Object-Oriented Programming Systems, Languages and Applications, pages 406-416, 1986. SIGPLAN Notices 22 (12).

....The trees of possibilities they explore have different roots and are rapidly evolving into a forest as diverse as the implementations of OO databases that exist now. One important concept that has arisen from the forest of formalization efforts is the concept of an object identifier [4, 17, 29, 31, 34, 45], itself stemming from the concept of a surrogate [14, 27] In this paper, I try to develop a theory of objects, using the concept of object identifier (oid) as root from which to develop and formalize other concepts. The language defined in this process is called CMSL (Conceptual Model ....

S.N. Khoshafian and G.P. Copeland. Object identity. In Object-Oriented Programming Systems, Languages and Applications, pages 406416, 1986. SIGPLAN Notices 22 (12).

....specify queries of a DB. The work reported in this summary started from a study of the semantic modeling structures found in TAXIS [7] SDM [18] and Galileo [1] and of the object oriented structures found in Orion [4] and O 2 [3] It is heavily based on the concept of object identifier [20]. The algebraic approach to object specification is partly inspired by work done on FOOPS [16] and OBJ3 Some differences with these last approaches are that VSL is more elementary than the value specification language underlying FOOPS and that OSL is centered more explicitly around the concept of ....

S.N. Khoshafian and G.P. Copeland, "Object Identity," Object-Oriented Programming Systems, Languages and Applications, pp. 406-416, SIGPLAN Notices 22 (12) (1986).

....transferred information alone whether the transferred information is about an object already represented by A, and if so, which one this is. This problem arises whenever the receiver uses a different naming scheme than the sender does. This may occur in federated databases [7] in database merges [9] and in EDI networks. For example, when two vehicle databases are combined that use different keys (or oid schemes) for vehicles, it is impossible to determine on the basis of keys (or oids) alone whether two tuples represent the same vehicle. We define the usage scope of a naming scheme as the ....

S.N. Khoshafian and G.P. Copeland. Object identity. In Object-Oriented Programming Systems, Languages and Applications, pages 406-- 416, 1986. SIGPLAN Notices 22 (12).

....the semantic neighborhood matching is also equal to zero. N stadium stadium structure athletic field sports arena w w w w w ( 1 = 12a) N stadium stadium entity type s s s ( 1 = 12b) Analogous to the notion of shallow and deep equality in object orientation [53, 54], semantic neighborhood matching defines shallow and deep matching depending on the radius of the semantic neighborhood. Shallow matching corresponds to an evaluation that is based on the similarity of the immediate neighborhood of entity classes (i.e. radius is 1) For semantic neighborhoods ....

Khoshafian, S. and G. Copeland. Object Identity. in OOPSLA. 1986. Portland, OR.

....languages such as QBD [2] G [10] ERC[11] and GRAQULA[26] are based on relational or entity relationship (ER) models. Even though these visual query languages and their simple extensions may 2 simulate the notion of path expressions by valued based joining without the notion of object identity[1, 5, 18], they fail to support the proper semantics simply due to the limitation of the underlying models. Despite that there are only few graph based visual query languages proposed for object oriented models[7, 14, 24] they explicitly model neither the nested structures nor the notion of set constructs ....

Khoshafian, S.N. and Copeland, G.P., "Object Identity," In ACM OOPSLA'86 Proceedings, pages 406--416, Sep.1986.

....to implement both purposes in an extremely efficient way. In the following paragraphs we discuss the idea of separating the notions of reference and comparison and some of its consequences. Our approach can be illustrated with an implementation technique called Identity Through Indirection in [3]: Here, a reference to an object is realised as an object oriented pointer (OOP) An OOP is an entry in an object table, which holds physical memory addresses. In our approach, the sole purpose of an OOP is 1 For example, see the Smalltalk FAQ [5] for further details. Figure 4: The supervisor ....

....this causes the redirection of several object references to reference an object OOPs are never compared. To be able to compare objects we could use the memory addresses stored in the object table, but instead we combine Identity Through Indirection with Identity Through Surrogates [3]: Each object is supplemented with an attribute storing a comparand. 2 Comparands are system generated, globally unique values, that cannot be directly manipulated by a programmer. Comparing objects then means comparing their comparands, but they are never used for referencing (see figure 5) ....

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Khoshafian, Setrag N.; Copeland, George P.; Object Identity, OOPSLA '86 Proceedings, 406416, September, 1986.

....of objects is called replication safe. The following definitions are introduced in order to enable a more precise specification of objects that are replication safe in the above mentioned way. At first, the identity of objects has to be examined. Identity is a key feature in object systems[8][17] In middleware environments object identity is prescribed by the object model which defines object references as globally unique object identifiers. Object Identity: Objects are identical if their references address the same object. Replicas cannot be identical because this would make load ....

S. Khoshafian and G. Copeland. Object Identity. In Conference on Object-Oriented Programming Systems, Languages, and Applications (OOPSLA'86). ACM, 1986.

....identity is independent of attribute values and is achieved by equipping each database object with a unique identifier. Several advantages accrue with attribute independent identity : arbitrarily complex objects can be represented, objects can share common sub objects, and updates are simplified [4, 7, 11]. As well as attribute independent ################ Appeared in Data Knowledge Engineering, Vol. 6, No. 3, pp. 205 224, 1991. 2 object identity, it is generally accepted that object oriented data models should provide mechanisms for inheritance between classes of objects and for the ....

....Value schemes comprise a set of attributes which can be either atomic or multi valued and nesting of attributes is possible. An object over a value scheme is a pair i,v , where i is the unique object identifier (object id) and v is the object value. Our representation of objects subsumes that of [11, 12] in which all objects are constrained to have object ids regardless of the level of nesting. In contrast, in GROOVY the S component of an object schema indicates all the sub object schemas and only objects and sub objects must have an object id. In other words, we argue that object ids should only ....

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KHOSHAFIAN S. N., AND COPELAND G. P. 1986. Object identity. Proceedings of Object-Oriented Programming Systems, Languages, and Applications, pp. 406-416. 20

....and Machiavelli have built in deep equality semantics, whereas O , for example, utilizes shallow equality for sets of objects. Languages with add on bulk data types (like PS algol, Napier 88, Eiffel or Smalltalk) rely heavily on reference semantics (L value bindings [AM88] object identity [KC86] Implementations of collections of composite objects in these languages typically store references to collection elements and often provide a shallow equality test in addition to the built in identity test. Because of this sharing, an update to a collection element, like person1.age: 36; in ....

S. Khoshafian and G. Copeland. Object Identity. In Proc. of 1st Int. Conf. on OOPSLA, Portland, Oregon, October 1986.

....network, and relational data models. Many of the newer approaches support a concept of object identity,by whichwe mean that an object has an existence which is independent of its value# two objects can either be identical (they are the same object) or they can be equal (they have the same value) [20, 5]. In the complex object databases with object identity,anobject O 0 ( referencing object ) can include within its attribute value the object identifiers of the other objects O 1 #O 2 #: #O n ( referenced objects ) and hence, logical connections between the objects are explicitly represented as ....

....discusses applications and extensions of persistentcaching. VI.A Application of Persistent Caching 1) Application to Efficient Object Locating: In many systems that manipulate complex objects, objects are identified by unique location independentidentifiers, which are sometimes called surrogates [28, 20]. Such a system requires object locating, i.e. transforming location independent identifiers to physical addresses on the execution time. A common method to accelerate object locating is to maintain primary or secondary indices on the location independent identifier fields of objects. Persistent ....

S. Khoshafian and G. Copeland. Object identity. In Proc. ACM OOPSLA'86, pages 406--416, October 1986.

....and straightforward correlations with real world concepts. Many authors side step the quality issue by describing the general elements of the object oriented paradigm, including identity, classification, abstraction, and encapsulation, but without giving any quality 1 assessment criterion [2, 8, 10, 11, 12, 15]. Although informal descriptions of these elements provide a framework for evaluating quality, they do not provide the means. Other approaches focus on class definitions with principles like sufficiency, completeness, and primitiveness [1] These principles are useful for verifying ....

Khoshafian, S. N. and G. P. Copeland, "Object Identity," Proceedings of the 1986 Object-oriented Programming Systems, Languages and Applications, September, 1986, pp. 406-416.

....a finite set of class names, and PALOPOLI AND TORLONE: GENERALIZED PRODUCTION RULES FOR ACTIVE AND DEDUCTIVE DATABASES 3 ffl typ is a function that associates to each symbol in C an ODM tuple type. 3 We also allow to express explicit references among classes through object identifiers (oid s) [16]. At the schema level, this is implemented by augmenting the set of basic types with the set C, that is, by allowing the use of class names in constructing types. For instance, we can define the class person whose type is composed by an attribute name of type string and an attribute spouse of type ....

S. Khoshafian and G. Copeland. Object identity. In ACM Symp. on Object Oriented Programming Systems, Languages and Applications, 1986.

....# # lm # ) ah# ### #, K#;Q### ae #ae,#ae,#chim ae,#### ffi # # j # # =K#;Q ###j # ### ### #j . j ###### ### ### ###cg # 2 :# #### ffi # ## 2L i OE 3 ,#j . Cat91, Pop91] ffl =K#;Q # #ae (object identifier) ahXZ#3 # #### =K#;Q### ### # =K#;Q### ae ae,# ### j # j . [KC86] ### #9L2L ###CK# ) ae ### #######.#p## f ffi #### ffi.#chim =K#;Q# CK#,# 9L ahXZ#9L# ## # f### =K#;Qffi #:L # ) f #:Lm# #### ffi ### # ## j ### =K#;Q### # : #### ae ### ####j . ### ]f # =K#;Q###### sv## ### j # m#j . ffi #### j #2MHL )7L ah### ILVW h### U[ ....

Setrag Khoshafian and George P. Copeland. "Object Identity". In ACM OOPSLA Conference Proceedings, pages 406--416, September 1986.

....portion is non empty, then that exact behaviour is executed, as described before. When the message has an empty behaviour portion, and the value part is an aggregate, then the direct parts of the aggregate, in other words the attributes values, are sent as messages to deep copies (as de ned in [KC86]) of the receiver in parallel. When the message has an ordered member part, in other words has a sequence structure, the rst member of this sequence is sent, as a message to the original receiver, and the subsequent members of the sequence are sent to the result of the previous message. In other ....

....or : using parenthesis as desired. Legal atoms are de ned as follows: De nition 25: Atoms. A legal atom in the KBO algebra has one of the following forms: x y, where x and y 1. are object variables or constants, 2. are dotted object variables (i.e. x or y) representing a deep copied [KC86] object variable, that is, x copies all the values but no identities from x such that x x but x 6 x, 3. denote a message sending of the form s L 1 : o 1 ; L n : o n ; r or s L 1 : o 1 ; L n : o n 1 ; r where s; r; o 1 ; o n are object variables or ....

Khoshaan, S.N., and Copeland, G.P. Object Identity. Proc. OOPSLA '86 , Sept. 1986, 406-416.

....are not aware of each other and the player object is not aware of any of its roles. This raises an identification paradoxon since now accessing all properties of a conceptual object having many roles requires a set of object identifiers, contradicting the widely accepted definition of identifier ( KhCo86] which requires that one unique identifier allows access to the whole object. Even role models that retain one unique identity for an object do not provide a satisfactory solution. They either allow to access an object as a whole, but do not define the semantics of dynamic binding when ....

S.N. Khoshafian, G.P. Copeland: "Object identity". In Object-Oriented Programming Systems, Languages and Applications, pp. 406-416, 1986. SIGPLAN Notices 22 (12)

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Khoshafian, S., & Copeland, G. (1986). Object identity. In Proceedings of the OOPSLA '86 Conference (pp. 406--416). New York: ACM Press.

No context found.

Khoshafian, S., and G. P. Copeland, "Object Identity", ACM Proceedings of the Conference on Object-Oriented Programming Systems, Languages, and Applications (OOPSLA), Portland, OR, September 1986. Also in [61]. 142

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S.N. Khoshafian and G.P. Copeland. Object Identity. In S.B. Zdonik and D. Maier, editors, Readings in Object-Oriented Database Systems, pages 37--46. Morgan Kaufmann, San Mateo, California, 1990.

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S. Khosha an and G. Copeland. Object identity. Proceedings OOPSLA'86. SIGPLAN Notices, 21(11):406-416, November 1986.

No context found.

Setrag Khoshafian and George Copeland, "Object Identity", Proc. Conf. on Object-Oriented Programming Systems, Languages, and Applications (OOPSLA), Portland, Oregon, 1986.

No context found.

S. Khoshafian and G. Copeland. Object identity. In ACM Symp. on Object Oriented Programming Systems, Languages and Applications, 1986.

No context found.

Setrag N. Khoshafian, George P. Copeland, "Object Identity", Proc. 1986 ACM Conference on Object Oriented Programming Systems, Languages and Applications, pp. 406-416.

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