Java 5.0 Tiger: A Developer's Notebook

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 chapters—let’s get to it.

Using Type-Safe Lists

One of Java’s greatest strengths is its typing. Everything is an ...