Java Thread Programming

Chapter 17. The BooleanLock Utility

IN THIS CHAPTER

• Background

• BooleanLock Class

• Inter-Thread Signaling Using BooleanLock

• Avoiding Blocking on synchronized

• Noticing Brief Changes in Value Using TransitionDetector

The BooleanLock class, which I present in this chapter, provides a useful encapsulation of a boolean variable that is easily and safely accessed from multiple threads. These threads can test and set the internal value and wait for it to change. The wait/notify mechanism is used internally to support waiting for the value to change, and frees external classes from the error-prone complexity of properly implementing this mechanism.

Background

Using the wait/notify mechanism effectively and correctly requires discipline. It is easy to erroneously ...