September 2018
Intermediate to advanced
398 pages
9h 43m
English
Content preview from Scala Programming Projects
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Companion object
A class can have a companion object. It must be declared in the same file as the class, using the keyword object followed by the name of the class it is accompanying. A companion object is a singleton – there is only one instance of this object in the JVM. It has its own type and is not an instance of the accompanied class.
This object defines static functions or values that are closely related to the class it is accompanying. If you are familiar with Java, it replaces the keyword static: in Scala, all static members of a class are declared inside the companion object.
Some functions in the companion object have a special meaning. Functions named apply are constructors of the class. The name apply can be omitted when we call ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
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.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
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.