• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content

Loading…

Flash Player 9 (or above) is needed to view presentations.
We have detected that you do not have it on your computer. To install it, go here.

Like this presentation? Why not share!

Stoop sed-class initialization

on

  • 285 views

 

Statistics

Views

Total Views
285
Views on SlideShare
285
Embed Views
0

Actions

Likes
0
Downloads
0
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    Stoop sed-class initialization Stoop sed-class initialization Presentation Transcript

    • Elements of Design - Class initialization Class initialization
    • Class Methods - Class Instance Variables
      • Classes (Packet class) represents class (Packet).
      • Class instance variables are instance variables of class
      • They should represent the state of class: number of created instances, number of messages sent, superclasses, subclasses....
      • Class methods represent class behavior: instance creation, class initialization, counting the number of instances....
      • If you weaken the second point: class state and behavior can be used to define common properties shared by all the instances
    • Class Initialization
      • How do we know that all the class behavior has been loaded?
      • At the end !
      • Automatically called by the system at load time or explicitly by the programmer.
      • Used to initialize a classVariable, a pool dictionary or class instance variables.
      • ‘Classname initialize’ at the end of the saved files in Squeak
      • In postLoadAction: in VW
    • Example of class initialization
      • Magnitude subclass: #Date
      • instanceVariableNames: 'day year'
      • classVariableNames:
        • 'DaysInMonth FirstDayOfMonth MonthNames
        • SecondsInDay WeekDayNames’
    • Date class>>initialize
      • Date class>>initialize
      • "Initialize class variables representing the names of the months and
      • days and the number of seconds, days in each month, and first day of
      • each month. "
      • MonthNames := #(January February March April May
      • June July August September October November December ).
      • SecondsInDay := 24 * 60 * 60.
      • DaysInMonth := #(31 28 31 30 31 30 31 31 30 31 30 31 ).
      • FirstDayOfMonth := #(1 32 60 91 121 152 182 213 244 274 305 335 ).
      • WeekDayNames := #(Monday Tuesday Wednesday Thursday Friday Saturday Sunday )