Steps to Analyze and Design Object Oriented System

Object Oriented Analysis (OOA) :
Object-Oriented Analysis (OOA) is the first technical activity performed as part of object-oriented software engineering. OOA introduces new concepts to investigate a problem.

Object Oriented Design (OOD) :
An analysis model created using object-oriented analysis is transformed by object-oriented design into a design model that works as a plan for software creation. OOD results in a design having several different levels of modularity i.e., The major system components are partitioned into subsystems (a system-level “modular”), and data their manipulation operations are encapsulated into objects (a modular form that is the building block of an OO system.).
 

There are various steps/stages in the analysis and design of an object-oriented system as given in below figure :

1. Create a Use case model : 
   The first step in the analysis and design of an object-oriented system is to recognize the actors interlinked with the system. After that, create the use case and draw the use case diagram.
    
2. Draw activity diagram (If required) : 
   The activity Diagram demonstrates the dynamic nature of a system by creating the flow of control form activity. An activity addresses a procedure on some class in the framework that outcomes in an adjustment of the condition of the system. The below figure shows the activity graph handling a request to convey a few products.
    
3. Draw the interaction diagram : 
   A interaction diagram shows a collaboration, comprising a bunch of articles and their relationship, including the messages that might be dispatched among them. Interaction diagram address the unique perspective on a system.
   
   Steps for drawing interaction diagrams :
   
   • Initially, we ought to distinguish that the objects as for each use case.
   • Then we draw the sequence diagrams for each use case.
   • Then we draw the collaboration diagrams for each use case.
      
4. Draw the class diagram : The class diagram is responsible for showing the relationship between the classes. There are four types of relationships available in class diagrams :
   
   • Association -
     It is a semantic connection between classes. At the point when an association associates two classes, each class can send messages to the next in sequence or a collaboration diagram. They may be bi-directional or unidirectional in nature.
   • Dependencies -
     They connect two classes and are always unidirectional in nature and display that one class, depends on the definitions of another class.
   • Aggregations -
     They are a stronger form of association that shows the relationship between a whole and its parts.
   • Generalizations -
     They are used to display an inheritance relationship between the two classes.
      
5. Design of State chart diagrams : 
   A state chart is utilized to show the state space of a given class, the occasion that influences progress starting with one state then onto the next, and the activity that outcome from a state change. A state change graph for a "book" in the library management system is shown below :
    

    6. Draw component and development diagram : 
These diagrams address the static execution perspective on a system they are identified with class diagrams in that a segment ordinarily guides to at least one class, interface, or coordinated effort.