July 2013
Intermediate to advanced
370 pages
8h 27m
English
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13.1 Injecting Methods Using Categories
Groovy categories provide a controlled way to inject methods—the effect of method injection is contained
within a block of code. A category is an object that has the ability to alter a class’s MetaClass.
It does so within the scope of the block and the executing thread. It reverses the change when we exit the block. Categories can be nested,
and we can also apply multiple categories in a single block. We will explore the behavior and use of categories
using examples in this section.
Suppose we have a Social Security number in a String or StringBuilder. We want to
inject a method
toSSN
that will return the string in the format xxx-xx-xxxx.
Let’s discuss some ways to achieve this.
Say the ...
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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.
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.