5.4 Summary
In this chapter, we've examined some advanced
techniques for synchronization. We've learned about
the Java memory model and why it inhibits some synchronization
techniques from working as expected. This has led to a better
understanding of volatile variables as well as an understanding of
why it's hard to change the synchronization rules
imposed by Java.
We've also examined the atomic package that comes
with J2SE 5.0. This is one way in which synchronization can be
avoided, but it comes with a price: the nature of the classes in the
atomic package is such that algorithms that use them often have to
change (particularly when multiple atomic variables are used at
once). Creating a method that loops until the desired outcome is
achieved is a common way to implement atomic variables.
5.4.1 Example Classes
Here are the class names and Ant targets for the examples in this
chapter:
|
Description
|
Main Java class
|
Ant target
|
|---|
|
Swing Type Tester using atomic ScoreLabel
|
javathreads.examples.ch05.example1.SwingTypeTester
|
ch5-ex1
| |
Swing Type Tester using atomic animation canvas
|
javathreads.examples.ch05.example2.SwingTypeTester
|
ch5-ex2
| |
Swing Type Tester using atomic score and character class
|
javathreads.examples.ch05.example3.SwingTypeTester
|
ch5-ex3
| |
Calculation test using thread local variables
|
javathreads.examples.ch05.example4.CalculatorTest
|
ch5-ex4
|
The calculator test requires a command-line argument that sets the
number of threads that run simultaneously. In the Ant script, it is
defined by this property:
<property name="CalcThreadCount" value="10"/>
| 
