Java 1.5 Tiger A Developers Notebook [Electronic resources] نسخه متنی

Chapter 2. Generics

NOTE

In this chapter:

Using Type-Safe Lists


Using Type-Safe Maps


Iterating Over Parameterized Types


Accepting Parameterized Types as Arguments


Returning Parameterized Types


Using Parameterized Types as Type Parameters


Checking for Lint


Generics and Type Conversions


Using Type Wildcards


Writing Generic Types


Restricting Type Parameters





Without any further ado, I'm going to dive right into the deep end of the
pool. More than any other feature, Tiger (or whatever version it ends up
being labeled as) brings to the
table generics. While the name might
throw you, generics actually bring a greater degree of type safety to Java
than anything you could imagine. It's finally possible to create parameterized
types, lists that only accept Strings, and ditch all that annoying
class-casting code. Even better, you can limit types that your custom
classes and methods accept, removing a huge amount of tedious errorchecking
and type-checking code.

Additionally, generics are foundational to many of the other features specific
to Tiger. Generics have a bearing on varargs, annotations, enumerations,
collections, and even some of the new concurrency utilities of the
language. While you may want to browse through other parts of this book,
you'd do well to take your time and really work through this chapter, lab
by lab. There, that's enough introduction for a few chapterslet's get to it.