Good for DJ over Java

1
(No Transcript)
2
Good for DJ over Java

• Extending traversals for collections (b..)
• returning a single object instead of a collection
  (Find)
• modifying the collection (Add, Delete)
• implementations are different for different
  implementations of collections

3
Embedding versus path control

• Embedding does mapping work once but requires
  mapping construct
• Path control may repeat mapping work

4
Reuse of an AC written with DJ

• Copy AC
• rename everything
• change path control assumes original AC is
  written with path control
• Leads to duplication of code

5
UML Class Diagram
BookName
bN
Book
Copy
Library
copies
books
0..
0..
avail
book
0..
checkOutItems
users
0..
uId
User
Boolean
UserId
6
UML Class Diagram
BookName
bN
Book
Copy
Library
copies
books
0..
book
0..
avail
copy
checkOutItems
0..
users
CheckOutItem
0..
uId
User
Boolean
UserId
7
How can addition be expressed with ACs

• Required participant graph
• Provided modified participant graph has all the
  paths in original but may have more

8
Interaction schema
Checkout a book for a user

• CheckOut
• Library(
• Find-gt Book Find(availtrue)-gt cCopy
• Find-gt uUser)
• addCopy
• uUser Add-gt Copy
• cCopy Set(avail,false)-gt Boolean
• //participants Library, Book, Copy, User

9
Compiler asks for information or determines it by
rules

• CheckOut (Library lib,BookName bN, UserId uId)
• libLibrary(
• Find(this.bNbN)-gt Book
• Find(availtrue)-gtcCopy
• Find(this.uIduId)-gt uUser)
• addCopy
• uUser Add(c)-gt Copy
• cCopy Set(avail,false)-gt Boolean

10
Compiler asks for information or determines it by
rules

• class Library
• Copy CheckOut
• (Library lib,BookName bN, UserId uId)
• Book b lib.Find(Book,bN,bN)
• Copy c b.Find (Copy,avail,true)
• User u lib.Find(User,uId,uId)
• u.Add(Copy,c)
• c.Set(avail,false) return c

11
For DJ

• class Library
• Copy CheckOut
• (Library lib,BookName bN, UserId uId)
• Book b cg.Find(lib,to Book,bN,bN)
• Copy c cg.Find (b,to Copy,avail,true)
• User u cg.Find(lib,to User,uId,uId)
• cg.Add(u,to Copy,c)
• cg.Set(c,to Boolean,avail,false)
• return c

12
Dougs proposal

• Book b cg.fetch(
• lib, new Strategy (to Book),
• new Predicate()
• boolean match(Object obj)
• return((Book) obj).get_isbn()
• 678)
• )

Instead of Book b cg.Find(lib,to
Book,isbn,678)
13
Dougs proposal
More flexible but more verbose

• Book b cg.fetch(
• lib, new Strategy (to Book),
• new Predicate()
• boolean match(Object obj)
• return((Book) obj).get_isbn()
• 678)
• )

Instead of Book b cg.Find(lib,to
Book,isbn,678) interface Predicate
boolean match(Object) Anonymous object of
anonymous class
14
For DJ/paper

• Book b cg.Find(lib,to Book,bN,bN)
• Copy c cg.Find (b,to Copy,avail,true)
• User u cg.Find(lib,to User,uId,uId)
• cg.Add(u,to Copy,c)
• Copy cg.Delete(u,to Copy, avail,true)
• cg.Set(c,to Boolean,avail,false)
• Boolean cg.Get(c,to Boolean,avail)
• int cg.Traverse(company,to Salary,v)

15
For DJ/paper/constraints

• 0.., 1..
• Book b cg.Find(lib,to Book,bN,bN)
• cg.Add(u,to Copy,c)
• cg.Delete(u,to Copy, avail,true)
• cg.Traverse(company,to Salary,v)
• cg.Gather(company,to Salary)
• 0..1, 1..1
• cg.Set(c,to Boolean,avail,false)
• cg.Get(c,to Boolean,avail)

16
For DJ/paper/constraints

• 0.., 1..
• Book cg.Find(lib,to Book,bN,bN)
• Find in library lib a book with data member
• bN bN.
• void cg.Add(u,to Copy,c)
• Add to user u a copy c
• Copy cg.Delete(u,to Copy, avail,true)
• Delete from user u a copy with avail true

17
For DJ/paper/constraints

• 0.., 1..
• int cg.Traverse(company,to Salary,v)
• traverse from company to Salary and perform
• visiting actions of v.
• Vector cg.Gather(company,to Salary)
• collect all Salary-objects reachable from
• company
• 0..1, 1..1
• Boolean cg.Set(c,to Boolean,avail,false)
• Boolean cg.Get(c,to Boolean,avail)

18
Aspect Language dont use

• CheckOut
• Find(this.bNbN)-gt Book
• Find(availtrue)-gtCopy
• Find(this.uIduId)-gt User
• addCopy
• uUser Add(c)-gt Copy

19
Compiler asks for information or determines it by
rules
Definition an interaction schema is a
sequence of navigation statements of the
form o1T1 -Action1-gt o2T2 -Action2-gt o3T3 ...

• CheckOut (lib,bN,uId)
• libLibrary(
• Find(this.bNbN)-gt Book
• Find(availtrue)-gt cCopy
• Find(this.uIduId)-gt uUser)
• addCopy only one choice
• uUser Add(c)-gt Copy
• cCopy Set(avail,false)-gt Boolean

20
Advantages

• High-level description of behavior in terms of an
  ideal UML class diagram
• Behavior can be adapted to many concrete class
  diagrams
• Some details of action parameters may be filled
  in under compiler control

21
Generalized Traversals

• Library Find-gt Book
• Traversal from Library to Book must have upper
  cardinality gt 1, e.g., 0.., 1...
• Compiler will ask for properties to select a
  book. Rule if an object of the class of a data
  member of Book is available, it will choose that
  one as default

22
Generalized traversals

• libLibrary Find-gt bBook
• DJ
• Book b cg.Find(lib,
• new Strategy(from Library to Book),
• property bN,bookName)
• Book b cg.Find(lib,
• new Strategy(from Library to Book),
• property isbn,isbnNumber)

23
Connection actions/class graph

• libLibrary Find-gt bBook
• uUser Add(c)-gt Copy
• libLibrary Delete-gt bBook
• 0.., 1..

24
Connection actions/class graph

• cCopy Set(avail,false)-gt Boolean
• cCopy Get(avail)-gt bBoolean
• cCopy Fetch(avail)-gt bBoolean
• 1..1, 0..1
• --- traverse a little different
• cCompany Traverse(v1)-gt rResult
• traverses to all classes mentioned in v1
• and performs visiting action. There must be a
  path to each such class?

25
Generalized traversals

• libLibrary Find-gt bBook
• DJ
• Book b cg.Find(lib,
• new Strategy(from Library to Book),
• property author,authorName)
• Find is like a generalized fetch

26
Generalized traversals

• uUser Add(c)-gt Copy
• cg.Add(u,new Strategy
• (from User to Copy), c)
• Expects a unique path from User to Copy
• that is insertable and it adds c at
• end. Insertable means ...

27
New Operations for DJ

• Find, Delete, Add
• Set, GetFetch
• Traverse, Gather
• cCopy Set(avail,false)-gt Boolean
• cg.Set(c, new Strategy(
• from Copy through -gt ,avail,
• to Boolean), false)

28
DJ dealing with vectors

• How can DJ deal with Java vectors and other
  collection classes?
• A B C. //from A via B to C
• B Vector.
• R Q. Q C.
• S T. T .

29
DJ dealing with vectors

• A B C. //from A via B to C
• B Vector.
• R Q. Q C.
• S T. T .

Q
A
C
R
T
S
Vector
B
30
DJ dealing with vectors

• A B C. //from A via B to C
• B Vector.
• R Q. Q C.
• S T. T .

Q
A
C
R
T
S
Vector
B
31
Dealing with Vector

• Enlarge the class graph by drawing a subclass
  edge from Vector to every node.
• Might create many edges
• Use the generality of the strategy compilation
  algorithm