Fireworks

Description of the problem:

The Fireworks applet is used to create a fireworks display for the viewer.  There is an
object to represent a starburst, which contains its center position, size, and size limit.

Description of the algorithm:

When the user enters the page on which the Fireworks applet is contained, the applet is
initialized wth method init.  A new thread is created for the applet with method start, and
the applet is then run with method run.  In run, each starburst is tested to see if it
has reached its size limit, and if so, a new starburst is created.  The screen is then
refreshed using method repaint.  When this occurs, method update is called, in which
method paint is called.  Here, the background is painted to an offscreen buffer.  Next,
the size of each starburst is expanded using method expand, and the starbursts are drawn to 
the offscreen buffer using method paint, both of which are contained in the Starburst class.
The starburst is painted by drawing each of the dots in the starburst ring one at a time to
the offscreen buffer.  Finally, the buffer is drawn to the screen using method drawImage.
When the user closes the applet, method stop is called to stop the active thread.

Classes:

Fireworks - Used to implement a fireworks display.  Randomly creates a given number of
starbursts which is determined by the value of the variable numStarbursts.  When a starburst
has reached its size limit, Fireworks creates another starburst and indirectly erases the old
one by painting over it with the background.

	Methods:
	
	init() - Override java.applet.Applet.init
	start() - Override java.applet.Applet.start
	stop() - Override java.applet.Applet.stop
	run() - Implement java.lang.Runnable.run
	update() - Override java.awt.Component.update
	paint() - Override java.awt.Component.paint
	
Starburst - Used to contain a singls Starburst.  It contains information about the center
position of the starburst, its color, and a size limit.  It also holds the current size of the
starburst.  In addition, it contains methods for manipulating a starburst.

	Methods:
	
	Starburst() - Starburst constructor which accepts the center coordinates of the starburst,
	the initial distance of the ring from the center, and the maximum distance allowed
	setColor() - sets the color of the starburst(access method)
	reachedLimit() - returns true if the distance of the ring from its
	center has reached the maximum distance
	expand() - increases the distance of the ring from its center by one
	paint() - paint the starburst on the offscreen buffer for display

References:

http://www.npac.syr.edu/projects/tutorials/docs/Sun/java2/docs/api/index.html - Java 2 API
specification was consulted for information about Random class in java.util package