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Nested and Enum Type in Java

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Page 1: Nested and Enum Type in Java

1 Prepared By: Prof. Ashish Bhatia

Nested TypeFor Semester – III [MCA]August 2012

Prepared byProf. Ashish [email protected]@asbspace.inwww.asbspace.in

Prepared Using

Page 2: Nested and Enum Type in Java

2 Prepared By: Prof. Ashish Bhatia

Note● This ppt is for teaching purpose only.

● The ppt may contain some material from

books/api documentation/internet.

● No intention of breaking any rights or what so

ever.

Page 3: Nested and Enum Type in Java

3 Prepared By: Prof. Ashish Bhatia

Nested Classes● The class define inside another class are

known as Nested Class.

● Top Level Nested Class● Inner class is static

● Inner Class

● Local Class

● Anonymous Class

Page 4: Nested and Enum Type in Java

4 Prepared By: Prof. Ashish Bhatia

Why we need nested class?● Logical Grouping of class

● Helper classes

● Increase encapuslation

Page 5: Nested and Enum Type in Java

5 Prepared By: Prof. Ashish Bhatia

Top Level Nested Class● Static member class is also known as top level

nested class.

● Member class and enclosing class shares trust

replationship in that they can access each

other memebers, including private members.

Page 6: Nested and Enum Type in Java

6 Prepared By: Prof. Ashish Bhatia

Page 7: Nested and Enum Type in Java

7 Prepared By: Prof. Ashish Bhatia

Inner Classes● Non-static member classes.

● Relationship : ● We cannot have an instance of innerclass without

having instance of the outer class.

● Used to represent one to many relationship.

● Eg : Account Class [Outer]and Transaction

class[Inner]● We cannot have transaction without Account

● Inner class cannot have static members.

Page 8: Nested and Enum Type in Java

8 Prepared By: Prof. Ashish Bhatia

Page 9: Nested and Enum Type in Java

9 Prepared By: Prof. Ashish Bhatia

Local Class● Class inside a method, constructor or intializer

block.

● This class donot have access specifier and

cannot be dcelared static / non-static.

Page 10: Nested and Enum Type in Java

10 Prepared By: Prof. Ashish Bhatia

Page 11: Nested and Enum Type in Java

11 Prepared By: Prof. Ashish Bhatia

Anonymous Class● Do not have name.

● Defined and created at same place.

● Become part of expression.

● Single inheritance type either extend or

implement

● Always non-abstract.

Page 12: Nested and Enum Type in Java

12 Prepared By: Prof. Ashish Bhatia

enum Type● Java 5 onwards.

● Cannot have super class but can implement

interface.

● Number of instances are fixed.

● ; required after declaration.

● Sub class of Enum

● Instances have name and ordinal value.

Page 13: Nested and Enum Type in Java

13 Prepared By: Prof. Ashish Bhatia

enum Type

● Each instance are static and final.● Ordinal Value starts from 0 ● To access Month.January ● Enum type are comparable [ ordinal]● Values and Valuesof ● public static Month[] values()● public static Month valueOf(String n)