What My Master Thesis is About

Transcript

1. Type System a for Organizing the Object Soupin Ambient-Oriented Applications Nick De Cooman
2. &%*.* 2 Alias Encapsulated objects Aggregate object No restrictions; Objects can be accessed from everywhere Consider a simple data structure
3. *(+*+(
   "*
   ' 3 Aliasing is restricted depending on the kind of object
4. .$'# 4 Consider a sorted linked list Local Reference Elements are sorted from small to large 21 53 60 89 34 Alias to encapsulated object
5. #!)!%
   )
   *&
   (&#$) 5 May affect correctness of aggregate object It might get bypassed by direct aliases to internal objects Elements are NOT sorted anymore ! 21 53 12 89 34 Assume Value gets updated through alias
6. -%() !'
   /') 6 Purpose ‣ Structure the object store/soup/heap ‣ Restrict reference passing and specify operations that can be performed on references. Confine an object inside a data structure Prevent representation exposure Statically enforced At compile-time
7. -&
   !%)
   &
   -%() !'
   ''(& ) 7 Owner-as-dominator Owner-as-modifier Read Update
8. #.!#
   #!)
   (&**!&% 8 Representation objects: Internal objects for which no reference outside the container can exist. Argument objects: Can be accessed from elsewhere, but are treated as being immutable. ECOOP ‘98 Code example
9. !$!**!&%)
   &
   #.!#
   #!)
   (&**!&% 9 Consider a simple list with iterator size content TOO RESTRICTIVE! content iterator Iterator Cannot be used by the outside size iterator Iterator Cannot access internal representation Possibilty 1 Possibilty 2
10. -%() !'
    /')
    &(
    "*
    %')+#*!&% 10 Allow instances of inner classes to access the representation of the instances of the outer class they are associated with content size iterator POPL ‘03
11.  *
     !)
     )!)
    !)
    &+* 11 Organize distributed object heap through ownership types Distributed environment actor Remote reference
12.  *
     !)
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    ##/
    !)
    &+* 12 Organize remote references
13. * &&#&/ 13 Type System a for Organizing the Object Soupin Ambient-Oriented Applications Both implementation and formal semantics AmbientTalk Supervised by
14. /
    ''(& 14 Type of Access Inwards Cardinality Initial proposal Ability to specify which action a remote object can execute on an object Ability to specify how many remote references can point to an object Annotate or tag values to achieve desirable behaviour Inwards Cardinality 0 = LOCAL OBJECT Make an object to be treaten immutable Limit the number of remote references
15.  %-()
    (!%#!*/ 15 Local objects cannot be remotely accessed No remote reference can ever exist @local Only 1 external reference is allowed at a time @unique External uniquenss 1 0 Cardinality Cardinality
16.  %-()
    (!%#!*/ 16 Limit the number of remote references to N. @cardinality: N N At each point in time, only N references can be used def futRef := waitFor: uniqueRef; when: futRef becomes: { |ref| // DO COMPUTATION // ref<-release() } Install listener to wait for reference to be obtained Regular future object Release reference so that it can be obtained by other actor Cardinality
17. /'
    &
    )) 17 State of the object cannot be modified by the outside @readOnly Only read operations are allowed def profile := object: { def getName(){...}; def setName(n)@mutator{...}; } taggedAs: [readOnly] Annotate mutator method to indicate that it changes the object state Can only be executed locally
18. !$#!% 18 FEB Literature study First proposal First iteration Second proposal 1-APR 15-APR Second iteration Formαl Semαntics JUN AUG Writing MAR 16-APR 30-APR Validation 1-JUN 15-JUN MAY
19. &%#+)!&% 19 @local 0 @unique 1 Limit the number of remote references to N. @cardinality: N N Organize remote references through various kind of ownership annotations. 2 dimensions Inwards Cardinality Type Of Access State of the object cannot be modified by the outside @readOnly Local objects cannot be remotely accessed Only 1 external reference is allowed at a time
20. Type System a for Organizing the Object Soupin Ambient-Oriented Applications Nick De Cooman