2.7 Summary
In this chapter, we've had our first taste of
threads. We've learned that threads are separate
tasks executed by a single program. This is the key to thinking about
how to design a good multithreaded program: what logical tasks make
up your program? How can these tasks be separated to make the program
logic easier, or benefit your program by running in parallel? In our
case, we have two simple tasks: display a random character and
display the key that a user types in response. In later chapters, we
add more tasks (and more threads) to this list.
At a programming level, we've learned how to
construct, start, pause, and stop threads. We've
also learned about the Runnable interface and how
that interface allows us a great degree of flexibility in how we
develop the class hierarchy for our objects. Tasks can be either
Thread objects or Runnable
objects associated with a thread. Using the
Runnable interface allows more flexibility in how
you define your tasks, but both approaches have merit in different
situations.
We've also touched on how threads interoperate by
calling methods on the same object. The ability of threads to
interoperate in this manner includes the ability for them to share
data as well as code. That data sharing is key to the benefits of a
multithreaded program, but it carries with it some pitfalls. This is
covered in the next chapter.
2.7.1 Example Classes
Here are the class names and Ant targets for the examples in this
chapter:
|
Description
|
Main Java class
|
Ant target
|
|---|
|
Factorial Example
|
javathreads.examples.ch02.example1.Factorial number
|
ch2-ex1
| |
First Swing Type Tester
|
javathreads.examples.ch02.example2.SwingTypeTester
|
ch2-ex2
| |
Type Tester (with Stop button)
|
javathreads.examples.ch02.example3.SwingTypeTester
|
ch2-ex3
| |
Type Tester (uses interrupt() method)
|
javathreads.examples.ch02.example4.SwingTypeTester
|
ch2-ex4
| |
Type Tester (uses Runnable interface)
|
javathreads.examples.ch02.example5.SwingTypeTester
|
ch2-ex5
| |
Type Tester (Runnable and interrupt())
|
javathreads.examples.ch02.example6.SwingTypeTester
|
ch2-ex6
| |
Type Tester (animated display)
|
javathreads.examples.ch02.example7.SwingTypeTester
|
ch2-ex7
|
The factorial program accepts a command-line argument to indicate the
integer whose factorial should be calculated; that can be set with
this Ant property:
<property name="FactorialArg" value="10"/>
| 
