Your SlideShare is downloading. ×
0
2   m2.w3.d1 - encapsulation
2   m2.w3.d1 - encapsulation
2   m2.w3.d1 - encapsulation
2   m2.w3.d1 - encapsulation
2   m2.w3.d1 - encapsulation
2   m2.w3.d1 - encapsulation
2   m2.w3.d1 - encapsulation
2   m2.w3.d1 - encapsulation
2   m2.w3.d1 - encapsulation
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

2 m2.w3.d1 - encapsulation

183

Published on

Published in: Education, Technology, Business
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
183
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
5
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Encapsulation Monday, October 14, 13
  • 2. Encapsulation • encapsulation is hiding or protecting the implementation details of an object from users of the object • this creates an abstraction which allows us to focus on essential properties rather than inner details 2 Monday, October 14, 13
  • 3. Private fields • To encapsulate the fields of an object, we make them private: public class Point { private int x; private int y; } • Only visible within the Point class, but not anywhere else 3 Monday, October 14, 13
  • 4. Accessors • We need a way for external code to access x and y: // can’t access private vars System.out.println("p1 is (" + p1.x + ", " + p1.y + ")"); // Point class, with *accessors* public class Point { private int x; private int y; public int return } public int return } } Monday, October 14, 13 getX() { x; getY() { y; 4
  • 5. Accessors • Write a program called PointMain that creates a new Point at (3, 5) and prints a description of the Point public class Point { private int x; private int y; public Point(int x, int y) { self.x = x; self.y = y; } public int return } public int return } } Monday, October 14, 13 getX() { x; getY() { y; 5
  • 6. Accessors public class PointMain { public static void main(String[] args) { Point p = new Point(3, 5); System.out.println("p is (" + p.getX() + ", " + p.getY() + ")"); } } 6 Monday, October 14, 13
  • 7. Mutators • Write a method for Point called setLocation that takes two integers and sets the x and y coordinates of the Point public class Point { private int x; private int y; public Point(int x, int y) { self.x = x; self.y = y; } public int return } public int return } } Monday, October 14, 13 getX() { x; getY() { y; 7
  • 8. Mutators public class Point { private int x; private int y; public Point(int x, int y) { self.x = x; self.y = y; } public int getX() { return x; } public int getY() { return y; } public void setLocation(int newX, int newY) { x = newX; y = newY; } } Monday, October 14, 13 8
  • 9. Lab! • See https://dl.dropboxusercontent.com/u/20418505/Labs/ M2.W3-0.txt 9 Monday, October 14, 13

×