1. Midterm Review CSU 670
Spring 2004

2. AP Late binding of data structures
Programming without accidental data structure details yet handling all those details on demand without program change

3. Concepts needed (DJ classes)
ClassGraph
Strategy
Visitor
ObjectGraph
TraversalGraph (efficiency)
ObjectGraphSlice (efficiency)

4. Strategy ClassGraph ObjectGraph Adaptive Programming is use-case based
Bold names
refer to DJ
classes.
is use-case based
abstraction of
ClassGraph
New: abstractions of class diagrams
notice affinity to design patterns: some of them also talk about families
of class structures
explain strategies
defines family of
ObjectGraph

5. Strategy ObjectGraph ObjectGraphSlice Adaptive Programming
defines traversals of
ObjectGraph
plus Strategy defines
explain strategies
ObjectGraphSlice

6. Strategy Visitor Adaptive Programming guides and informs
explain strategies
Visitor

7. Software Design and Development with DJ (very brief)
Functional decomposition into generic behavior
Decomposition into methods
Decomposition into formal traversal strategies
Decomposition into visitors
Adaptation of generic behavior
Identify class graph
Identify traversal strategies

8. Definition: Class Graph
A class graph is a directed graph with a partial order on the nodes. We write c1 -> c2 for the edges (construction edges) and c1 <= c2 for the order (inheritance edges -- c1 is a subclass of c2).
We write => for the inverse of <=.

9. Relations We think of directed graphs as relations.
Write C(c1,c2) or c1 C c2 for edge from c1 to c2 in C.
Composition of relations by . E.g., x (R.S) z iff there is a y such that xRy and ySz.
R* is the reflective transitive closure of a relation R.

10. Strategy: From X1 to T o1:X1 o2:X2
declared type of target of e is X3 =>X2 e
go down e iff X1 <=.e X3 =>.(<=.C.=>)*.<=) T
if only construction edges:
go down e iff X1 e X3 C* T

11. z
Strategy
S -> T x X1 Y1 Z1 y S X2 Y2 Z2 T t X3 Y3 Z3 x y z t
s1:S
x31:X3
y31:Y3
z31:Z3
t1:T
go down e iff S <=.C X1 =>.(<=.C.=>)*.<=) T

12. z
Strategy
S -> T x X1 Y1 Z1 y S X2 Y2 Z2 T t X3 Y3 Z3 x y z t
s1:S
x31:X3
y31:Y3
z31:Z3
t1:T
go down e iff S <=.C X1 =>.(<=.C.=>)*.<=) T

13. z
Strategy
S -> T x X1 Y1 Z1 y S X2 Y2 Z2 T t X3 Y3 Z3 x y z t
s1:S
x31:X3
y31:Y3
z31:Z3
t1:T
<=,=>
not
used
go down e iff S <=.C X1 =>.(<=.C.=><=.C.=><=.C=>).<=) T

14. Example strategy A -> T T -> D a1:A 0..1 :D r1:R X 0..1 B c1:C
s1:S D A C
s2:S
t1:T
0..1
r2:R
object graph R S T
0..1
c2:C
class
graph
d2:D
go down e iff A <=.C R =>.(<=.C.=>)*.<=) T

15. Example 2 S = from BusRoute through Bus to Person busStops BusRoute
BusStopList
buses
0..*
NGasPowered
BusStop
BusList
waiting
0..*
passengers
Bus
PersonList
Person
0..*
DieselPowered

16. Example 2 OG : BR BL DP PL P OG’: BR BL B PL P SG : BR B P
Only node paths shown for space reasons
Route1:BusRoute
BusList
buses
busStops
:BusStopList
Bus15:DieselPowered
passengers
CentralSquare:BusStop
waiting
:PersonList
:PersonList
Joan:Person
Paul:Person
Seema:Person
Eric:Person
S = from BusRoute through Bus to Person

17. Example 3 OG : BR BL OG’: BR BL SG : BR
Only node paths shown for space reasons
early
termination
Route1:BusRoute
BusList
buses
busStops
:BusStopList
Bus15:DieselPowered
passengers
CentralSquare:BusStop
waiting
:PersonList
:PersonList
Joan:Person
Paul:Person
Seema:Person
Eric:Person
S = from BusRoute via NGasPowered to Person

18. A simple view of traversals
When a traversal reaches a target node in the object graph, the path traversed from the source, with suitable substitution of subclasses by superclasses, must be an expansion of an s-t path in the strategy graph. s is the source and t is the target of the strategy. Each edge in the strategy graph corresponds to at least one edge in the object graph.

19. A simple view of traversals
When a traversal reaches a final node in the object graph without being at a target, the path traversed from the source, with suitable substitution of subclasses by superclasses, must be a prefix of an expansion of an s-t path in the strategy graph. The prefix is the longest prefix such that there is still a possibility of success as determined by the class graph.

20. Object Graph Slice
The object graph slice starting with o1 is the slice built by following the edges selected by the path regular expression starting at o1 and continuing until every path terminates (at an object of type t or if it terminates prematurely).
go down e iff X1 <=.e X3 =>.(<=.C.=>)*.<=) T

21. Strategy definition: embedded, positive strategies
Given a graph G, a strategy graph S of G is any subgraph of the transitive closure of G.
The transitive closure of G=(V,E) is the graph G*=(V,E*), where E*={(v,w): there is a path from vertex v to vertex w in G}.

22. Transitive Closure busStops BusRoute BusStopList buses 0..* BusStop
BusList
waiting
0..*
passengers
Bus
PersonList
Person
0..*

23. Strategy graph and base graph are directed graphs
Key concepts
Strategy graph S with source s and target t of a base graph G. Nodes(S) subset Nodes(G) (Embedded strategy graph).
A path p is an expansion of path p’ if p’ can be obtained by deleting some elements from p.

24. class dictionaries (11 kinds)
inductive
nonleft-recursive 9 10 11 8 7 6 1 2
LL(1) 3
1: ideal case
2: JavaCC does not complain (Oct ). Grammar contains useless symbols. Ok if we don’t want to parse but forces cyclic objects. 4
nonambiguous 5
Venn Diagram
12/30/2018
AOO / Demeter

25. Patterns Patterns Structure-shy Traversal Selective Visitor
Structure-shy Object
Class Graph
Growth Plan Pattern

26. Three layers of Demeter
instance of
defines classes
Demeter behavior and aspect files
B: metamodel
L: model
P: user objects CB
your behavior and aspect files CL
metamodel OB
classes
model OL TB
user object OP
a class dictionary
for class
dictionaries
objects TL
class
dictionary TP
text
sentence

27. Icon Use as reminder for Demeter Tiling. Demeter Tiling CB OB CL TB OL
TL OP TP

28. Example ??? Demeter Tiling CB OB CL Basket TB OL TL OP TP
aBasket:Basket
With respect to the project class dictionary as OB

29. Example Vertex (or Ident) Demeter Tiling CB OB CL Basket TB OL TL OPTP
Basket
aBasket:Basket
With respect to the project class dictionary as OB

30. Example ??? Demeter Tiling CB OB CL Regular_Syntax TB OL TL OP TP
aRegular_Syntax:Regular_Syntax
With respect to the project class dictionary as OB = OL

31. Example Vertex Demeter Tiling CB OB CL Regular_Syntax TB OL TL OP TP
aRegular_Syntax:Regular_Syntax
With respect to the project class dictionary as OB = OL

32. Example ??? Demeter Tiling CB OB CL
TB OL
TL OP TP
Labeled = <label_name> Ident ...
<b>
With respect to the project class dictionary as OB = OL

33. Example Adjacency = <source> Vertex ... Demeter Tiling CB OB CL
TB OL
TL OP TP
Labeled = <label_name> Ident ...
<b>
With respect to the project class dictionary as OB = OL

34. Example ??? Demeter Tiling CB OB CL
TB OL
TL OP TP
Adjacency = <source> Vertex ...
A = <b> B <b> B.
With respect to the project class dictionary

35. Example Adjacency = <source> Vertex ... Demeter Tiling CB OB CL
TB OL
TL OP TP
Adjacency = <source> Vertex ...
A = <b> B <b> B.
With respect to the project class dictionary

36. Lightweight Software Development Method
Extreme Programming
lots of testing, write test cases early
incremental development
pair programming

37. UML
class diagrams
object diagrams