Object Flow Graphs - ist.tugraz.at€¦ · Software)Maintenance 2 Object)Flow)Graphs)– Part)II Outline! Repetition! Program)abstraction! Graph)creation! Containers! NEW! Object)sensitivity!

Software MaintenanceObject Flow Graphs – Part II1

Object FlowGraphs(Part II)

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Outline

§ Repetition§ Program abstraction§ Graph creation§ Containers

§ NEW§ Object sensitivity§ Improvement of class diagrams


Outline




Why do we create

Object Flow Graphs?


Original Program

Abstract Program

Object Flow Graph

Activities


LanguageAbstraction


Language Abstraction

§ Data flow sensitive§ Fully scoped identifiers § Class members: package.class.id§ Method parameters: package.class.method.id

§ Control flow insensitive§ Ignore/Remove§ Primitive data types § Constants (even null)


Example 4


Example

4


Graph

Creation


Outline




Container

Container

C

Object

C.add(Object)

Object=C.get()

ObjectC = ObjectObject = C


Outline




Object sensitivity

§ Distinguish objects§ belonging to the same class§ but of different instances

§ Construction§ more complicated§ more precise propagation of information


Example

1. x = new Object();2. y = new Object();

Object.this

x

y

Object1.this x

yObject2.this

Object-insensitive Object-sensitive


Example

3

1. public class BinaryTreeNode 2. BinaryTreeNode left, right ;;3. Comparable obj;;4. public BinaryTreeNode (Comparable x ) 5. obj = x;; 6. 7. public class ToyCollection8. static Set toys = new TreeSet ();;9. public static void addToy (Toy t)10. BinaryTreeNode n = new BinaryTreeNode (t);;11. toys.insert(n);; 12. public static void main ()13. Toy t = new Toy("PS2”);;14. addToy(t);; 15. 16. public class Toy implements Comparable17. Object id;;18. public Toy( )19. id = null;; 20. public void name (Object name) 21. id = name;;22.


Outline




Class diagram recovery I


Class diagram recovery II


Howdo we

improve the Class Diagram?


Control of Study Objectives1. public class Animal2. String name;;3. public Animal(String name)4. this.name = name;;5. 6.

7. public class Zoo8. List animals = new ArrayList();;9. public static void addAnimal(String name)10. Animal a = new Animal(name);;11. animals.add(a);;12. 13. public static void main(String[] args)14. String garfield = “Garfield”;;15. addAnimal(garfield);;16. 17.

1) Generieren Sie das Abstrakte Programmund den OFG.

2) Zeichnen Sie das Klassendiagramm auf und zeigen Siegrafisch welcheVerbesserungen Siedurch den OFG erzielen können.


Control of Study Objectives2. Animal.name3. Animal.Animal(Animal.Animal.name)4. Animal.name = Animal.Animal.name;;8. Zoo.animals = new ArrayList.ArrayList();;9. Zoo.addAnimal(Zoo.addAnimal.name)10. Zoo.addAnimal.a = new Animal.Animal(Zoo.addAnimal.name);;11. Zoo.animals = Zoo.addAnimal.a;;13. Zoo.main(Zoo.main.args)14. Zoo.main.garfield = new String.String();;15. Zoo.main.this. Zoo.addAnimal(Zoo.main.garfield);;


Control of Study Objectives


Questions?

Documents

Object Flow Graphs - ist.tugraz.at€¦ · Software)Maintenance 2 Object)Flow)Graphs)– Part)II Outline! Repetition! Program)abstraction! Graph)creation! Containers! NEW! Object)sensitivity!