Attribute types and bracket implementations

et al. 2004

JOT

A new kind of type is described whose objects ("qualifiers") have bracket methods which can modify the run-time behaviour of other objects ("targets"). Bracket methods can qualify either specific methods of a target or can separately qualify their reader and writer methods, thus allowing general qualifiers to be developed for standard activities such as synchronisation, monitoring and protection. Qualifiers are associated with a target when it is created, in the form of a qualifier list. Individual qualifiers can be dynamically added to and removed from the list even while the target object is active.

“…This paper has described the basic concepts of qualifying types with bracket methods. The idea is based on earlier work in our group [7,8].…”

Section: Comparison With Other Workmentioning

confidence: 99%

“…synchronisation, monitoring, logging, protection and transaction control. Preliminary versions of this idea have been presented in [7,8] and the technique has been illustrated with respect to synchronisation in [12].…”

Section: Introductionmentioning

confidence: 99%

Qualifying Types with Bracket Methods in Timor.

Keedy¹,

Espenlaub²,

et al. 2004

JOT

“…insertAtPos) can be pruned where appropriate. In this example we see how t wo subtypes of the same behavioural supertype (Ordered) can be implemented by one re-using the code of another 8 . Further implementations of SortedList could be produced in the same way, by re-using SingleLinkList, DoubleLinkList, etc.…”

Section: Re-using Individual Implementationsmentioning

confidence: 99%

“…Next we consider how implementations of the six DuplFree types can be produced. 8 It would equally be possible first to provide an independent implementation of SortedList and then to reuse its code to implement List. JOURNAL OF OBJECT TECHNOLOGY VOL.…”

Section: Re-using Individual Implementationsmentioning

confidence: 99%

Inheriting from a Common Abstract Ancestor in Timor.

Keedy¹,

Menger²,

2002

JOT

A particular case of multiple inheritance, involving a family of related types with a common abstract ancestor, is examined, and a substantial example, involving five abstract and nine concrete collection types, is presented. The separation of types and implementations, together with the separation of subtyping and code re-use, results in a clearly structured and easily intelligible type library which allows extensive polymorphic use of collections at the type level. A full implementation of only one of these types, together with a few additional trivial code units, can be re-used to implement all nine concrete types. The paper concludes by describing how the binary methods and constructors can also be easily and efficiently designed and implemented.

“…types whose objects (known as "qualifiers") can dynamically qualify the behaviour of objects of other types (known as "targets") by means of bracket methods [5]. As presented in that and earlier papers [2][3][4], qualifying types permit modules to be written in the programming language Timor 1 which can, for example, provide such general services as synchronisation, protection and logging. The bracket methods which carry out such activities are applied to the incoming invocations of a target object's methods.…”

Section: Introductionmentioning

confidence: 99%

Call-out Bracket Methods in Timor.

Keedy¹,

Espenlaub²,

et al. 2006

JOT

This paper extends the concept of qualifying types by describing how their implementations can include not only bracket methods which are applied when a method of a target object is invoked, but also further "call-out" bracket methods which can be applied to invocations by the target object of the methods of other objects. This additional technique can be used for example to provide enhanced synchronisation in qualifying types, as an aid to confining the activities of an object, and as a means of providing parallel activities associated with the sending and receiving of information, e.g. encryption and decryption, data compression.