Transcript FP301 Object Oriented Programming

1.0
• Introduction To OOP
2.0
• Fundamentals Of Java Programming Language
3.0
• Exception Handling
4.0
• Classes, Inheritance And Polymorphism
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• Define modeling concepts: abstraction,
encapsulation, and packages.
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• Analyze a problem using object-oriented
analysis (OOA).
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• Create classes from objects using UML Class
Diagram
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• Identify components of a class
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• Construct main method () using appropriate
syntax
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• Apply escape sequence for special character
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Abstraction
• Abstraction is the process of exposing only
the relevant details and ignoring (hiding) the
irrelevant details (Don't get confused with
"datahiding" of the "Encapsulation").
• Abstraction simplifies the understanding and
using of any complex system.
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Encapsulation
• Through encapsulation, you can control what
parts of a program can access the members of
a class.
• How a member of a class can be accessed is
determined by the access modifier that modifies
its declaration.
• Java’s access modifiers are:
– public
– private
– protected
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Packages
• Is a collection of classes that can be shared by
Java programs.
• Are classified into


in-built packages – system packages
user-defined packages - Created by the users for their
requirements.
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• The classes are grouped together based on their
functionality.
• Some of the important packages of Java are:



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

lang
util
io
awt
net
applet
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• Analysis:
Precise abstraction of what the desired system must do, not how it will be done.
Object-Oriented Analysis is method which examines requirements from the
perspective of the classes and objects.
• OOA Process:
Use Case Modeling – shows functions
Class-based Modeling – Class diagram, CRC
Behavioral Model – State Diagram, Sequence
Diagram
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Example : Illustrate and explain object oriented and analysis by develop an
information system to support all customer-related business in car rental company.
The system should support management of customer data, reservations, vehicle
rental and customer billing.
1) Identify problem domain : …………..
2) Objects: ……..
3) Attributes: …….
4) Operation: ……….
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Draw a class diagram based on scenario below:A customer makes order from retail catalog. Use Order as a central class.
Associated with the order are the Customer making the purchase and the
Payment.
A Payment is one of three kinds; Cash, Cheque or Credit.
The order contains OrderDetails, each with its associated Item.
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Possible Objects, attributes and behavior :-
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Example:
•Class : Bicycle
•Attributes/Behaviour  brand, colour, wheels, no of
gear
•Method/Operations  speed, speed, stop,
changeGear
Class
Notes:
•Public  +
•Private  -
Attributes /
behaviour
Method /
Operations
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Structuring Classes
• The class declaration
• Attribute variable declarations and initialization
(optional)
• Methods (optional)
• Comments (optional)
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Class Declaration
• Syntax:
[modifiers] class class_identifier
• Example:
public class Shirt
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Variable Declaration and Assignment
public int shirtID = 0;
public String description = “-description required-”;
public char colorCode = ‘U’;
public double price = 0.0;
public int quantityInStock = 0;
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Comments:
• A comment is text that is not part of your code but serves as guide
when trying to figure out what the lines of code of your program are.
• To comment the contents of one line, you start it with double forward
slashes like this //
Example :
//Here is where you put the comments
• You can include many lines of comments in your program. To do that,
comment each line with the double slashes. An alternative is to start
the beginning of the commented line or paragraph with /* and end the
commented section with */
Example :
/* Here is a simple sentence that I want to display when the program
starts. It doesn't do much. I am planning to do more stuff in the future. */
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Methods
• Syntax:
[modifiers] return_type method_identifier ([arguments]){
method_code_block
}
• Example:
public void displayInformation() {
System.out.println("Shirt ID: " + shirtID);
System.out.println("Shirt description:" + description);
System.out.println("Color Code: " + colorCode);
System.out.println("Shirt price: " + price);
System.out.println("Quantity in stock: " + quantityInStock);
} // end of display method
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1 public class Shirt {
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Class declaration
3 public int shirtID = 0; // Default ID for the shirt
4 public String description = "-description required-"; // default
5 // The color codes are R=Red, B=Blue, G=Green, U=Unset
6 public char colorCode = ’U’;
7 public double price = 0.0; // Default price for all shirts
Variable declaration and
assignment
8 public int quantityInStock = 0; // Default quantity for all shirts
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10 // This method displays the values for an item
11 public void displayInformation() {
12 System.out.println("Shirt ID: " + shirtID);
13 System.out.println("Shirt description:" + description);
14 System.out.println("Color Code: " + colorCode);
Method
displayInformation()
15 System.out.println("Shirt price: " + price);
16 System.out.println("Quantity in stock: " + quantityInStock);
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18 } // end of display method
19 } // end of class)
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• is a special method that the JVM recognizes as
the starting point for every Java technology
program that runs from a command line
• Syntax:
public static void main (String [] args)
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Sequence
Meaning
\b
Backspace
\t
Horizontal tab
\n
Line feed
\f
Form feed
\r
Carriage return
\”
Double quote
\’
Single quote
\\
Back slash
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// Program Welcome.java
public class Welcome {
public static void main (String args[])
{
System.out.println(“Welcome\nto\nJava!");
}
}
Output :Welcome
to
Java!
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