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Class and object_diagram
1. CLASS AND OBJECT DIAGRAMS
Submitted by:
Sadhana Singh
M.Tech(S.E.)
2. Contents
Introduction about Class Diagram
Common Uses of Class Diagram
Common Modeling Techniques for Class
Diagram
Introduction about Object Diagram
Common Uses of Object Diagram
Common Modeling Techniques for Object
Diagram
Difference between class and object diagram
3. Introduction about Class Diagram
Found in modeling object oriented system.
Use to model static design view of a system.
Main building block of Object Oriented
Modeling.
Describes the type of objects in system.
In the diagram these classes are represented with
boxes which contain three parts
◦ The upper part holds the name of the class
◦ The middle part contains the attributes of the class
◦ The bottom part gives the methods or operations the class can
take or undertake
5. Common Uses of Class Diagram
To model the vocabulary of system.
To model simple collaborations.
To model a logical database schema.
6. Common Modeling Techniques for
Class Diagram
Modeling simple collaborations.
Modeling a logical database schema.
Forward and Reverse Engineering.
7. Modeling simple collaborations
Identify the mechanism we had like to model.
For each mechanism, identify the classes,
interfaces, and other collaborations that
participate in this collaboration.
Use scenarios to walk through these things.
To populate these elements with their contents.
8.
9. Modeling a logical database schema
Identify those classes in our model whose state
must transcend the lifetime of their application.
Create a class diagram that contains these
classes and mark them as persistent.
Expand the structural details of these classes.
Watch for common patterns that complicate
physical database design.
Consider also the behavior of these classes by
expanding operations.
Use tools to help we transform our logical
design into a physical design.
10.
11. Forward and Reverse Engineering
Forward Engineering
Identify the rules for mapping to our
implementation language or languages of
choice.
Depending on the semantics of the languages we
choose, we may have to constrain our use of
certain UML features.
Use tagged values to specify our target
language.
Use tools to forward engineer our models.
12.
13. Forward engineering the class EventHandler
yields the following code.
public abstract class EventHandler {
EventHandler successor;
private Integer currentEventID;
private String source;
EventHandler() {}
public void handleRequest() {}
}
14. Reverse Engineering
Identify the rules for mapping from our
implementation language or languages of
choice.
Using a tool, point to the code we had like to
reverse engineer.
Using our tool, create a class diagram by
querying the model.
15. Introduction about Object Diagram
Gives snapshots of the system.
Shows a complete or partial view of structure of
a modeled system at specific time.
Derived from class diagrams.
Represent an instance of class diagrams.
To model the static design view.
16. Common Uses of Object Diagram
To model object structure.
17. Common Modeling techniques for
Object Diagram
Modeling object structures.
Forward and Reverse Engineering.
18. Modeling object Structures
Identify the mechanism we had like to model.
For each mechanism, identify the classes,
interfaces, and other elements that participate in
this collaboration; identify the relationships
among these things, as well.
Consider one scenario that walks through this
mechanism.
Expose the state and attribute values of each
such object, as necessary, to understand the
scenario.
Similarly, expose the links among these objects,
representing instances of associations among
them.
19.
20. Forward and Reverse Engineering
Reverse Engineering
We’ll set your context inside an operation or relative
to an instance of one particular class.
Using a tool or simply walking through a scenario,
stop execution at a certain moment in time.
Identify the set of interesting objects that collaborate
in that context and render them in an object diagram.
As necessary to understand their semantics, expose
these object's states.
As necessary to understand their semantics, identify
the links that exist among these objects.
21. Difference between Class and Object
Diagrams
A class diagram is a graph of Classifier elements
connected by their various static relationships
whereas an object diagram is a graph of
instances, including objects and data values.
Class diagrams can contain objects, so a class
diagram with objects and no classes is an object
diagram.
Class diagrams are the blueprints of your system
or subsystem whereas object diagram shows a
snapshot of the detailed state of a system at a
point in time.
