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
UML Class Diagram
BookName
bN
Book
Copy
Library
copies
books
0..
0..
avail
book
0..
checkOutItems
users
0..
uId
User
Boolean
UserId
5
UML Class Diagram
BookName
bN
Book
Copy
Library
copies
books
0..
book
0..
avail
copy
checkOutItems
0..
users
CheckOutItem
0..
uId
User
Boolean
UserId
6
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

7
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

8
Compiler asks for information or determines it by
rules

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

9
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

10
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)

11
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)

12
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

13
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)

14
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

15
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