Overview:

While in future weeks you may work with a partner, for this section you are to submit your own work. You are free to discuss implementation strategies with colleagues, but the work you turn in is to be your own.

Goals:

• Understand how to use wait and notifyAll to ensure a precondition holds for a given operation.
• Understand how to achieve race-free classes without obtaining locks.

Before starting:

• Read this entire document before you start.
• Review the lectures and readings on condition variables and preconditions.
• Read over the JavaDoc for this lab. There is much more in the JavaDoc than you need for this part; please concentrate on the pieces due for 6a.
• Run the sample solution

• Classes you are given, and need not modify:
  • Startup.java I'll post this after the weekend, and it will test your code...for now test on your own!
  • Scribbler.java
  • PCSable.java
  • Factory.java
• Classes you do not implement, but modify as part of this lab:
  • RectViz.java You have to augment this class to do some new things as described in the class's JavaDoc. You also have to make it thread-safe without getting a lock.
• Classes you do implement (stubs are given):
  • Queue.java
  • Reservoir.java

Complete the classes as described in the JavaDoc.

The Queue class is not documented, but there is a test included in that file (just run the file), so you can see how it works. A thread that tries to dequeue an object blocks until some object shows up in the queue.

What to turn in:

1. A code cover sheet.
2. Any Java files you have created or modified for this part.