February 2016
Intermediate to advanced
382 pages
8h 1m
English
Content preview from Scala Design PatternsBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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The observer design pattern
There are sometimes cases where some objects are interested in the state change of another object and want to perform some specific action when this happens. A common example could be whenever you click a button in an app, some other objects subscribe to the click event and perform some actions. The observer design pattern helps us to achieve this. The purpose of the observer design pattern is to:
Note
Have an object (called subject) that automatically notifies all of its observers of any state change by calling one of their methods.
The observer design pattern is employed in most GUI toolkits. It is also part of the MVC architectural pattern where the view is an observer. Java even comes with the Observable class and ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.