It is sad that CPA in Seneca doesn’t offer any course about Software Design Patterns.
I just read through chapter two about ‘Subject Observers Pattern’.
Subject Observers pattern is useful when a bunch of observer objects need to be notified about change in the subject object. Observers registers themselves to get notifications from the Subject. When there is a change in any data in Subject, the subject notifies all the observers about the change. The subject object maintains a list of all the observer objects. When an observer unregisters itself, it is removed from this list. So next time, the subject notifies all the observers in its list, the unregisters are not sent any more notifications.
For example, a weather tracking system that sends temperature information to all the clients every time the temperature changes.
Reading ‘Head First Design Patterns’
June 3, 2010 by ·
It is sad that CPA in Seneca doesn’t offer any course about Software Design Patterns.
I just read through chapter two about ‘Subject Observers Pattern’.
Subject Observers pattern is useful when a bunch of observer objects need to be notified about change in the subject object. Observers registers themselves to get notifications from the Subject. When there is a change in any data in Subject, the subject notifies all the observers about the change. The subject object maintains a list of all the observer objects. When an observer unregisters itself, it is removed from this list. So next time, the subject notifies all the observers in its list, the unregisters are not sent any more notifications.
For example, a weather tracking system that sends temperature information to all the clients every time the temperature changes.
Hi, Thupten.
Which book are you reading? The one by Gamma and others?
Hello Peter,
Thank for visiting my blog.
I am reading
Head First Design Patterns By Eric Freeman, Elisabeth Freeman, Bert Bates, Kathy Sierra
ISBN: 0596007124 Publisher: O’Reilly
I like this book mainly because of its funny and entertaining style of writing. Some of the diagrams actually reminds me of your famous donut objects from OOP244 classes.
Professor Marie from my SYS466 recommended this book to me.
I think its a great book for beginners.
What patterns do they cover in this book?
http://www.amazon.com/gp/reader/0596007124/ref=sib_dp_bod_toc/178-5624225-7931552?ie=UTF8&p=S00B#reader-link