DESIGN_DOC_PRELIM.txt

Part 1: Design Document
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###Necessary Packages and Classes

The basic classes should include Mass, Spring, and Muscle (which could possibly extend spring,
since "muscles" are what allow springs to bounce). Mass will include the physical properties of
a physical object in general; Spring should extend Mass because it is an object of mass; and 
Muscle should extend Spring, because Muscle will contain the physical properties of a spring
that will allow Spring objects to bounce with varying physical parameters.

The Mass class will take in parameters like the starting position (x and y coordinates) and 
starting motion (x speed and y speed). For the purposes of simulating spring-mass assemblies
persuasively, we will probably have to include the actual mass of the Mass object as well.
The Mass class will probably extend the PhysicalObject class in jboxGlue.

The Spring class will take in parameters for the length of the spring and the k-value of the
spring. To establish the position of the spring, we will take in parameters for the coordinate
of the center of the spring and its orientation (x and y coordinates). This class will also
extend PhysicalObject.

The Muscle class will extend the Spring class, and will allow for Spring objects to expand and
contract (and otherwise be like a spring). The Muscle class should take in parameters for the
amount of force placed on either of its ends (which could be either from a Mass object or
from an outside force like gravity). The Muscle class will also, at some point, use Math.sin()
to simulate the sinusoidal motion of a spring. There are also other features of Muscles in
SodaPlay that we have not explored very deeply, such as autoreversal of wave movement,
but it seems that the behaviors and the parameters of waves will factor heavily into the 
Muscle class. 

We looked at the project description and noticed that things like gravity, friction, and 
viscosity will also need to be taken into account. Speaking from a very high level, these 
forces could also be classes, and would affect the x- and y-direction speeds of masses and 
springs. Since these classes will concern speed, we could arrange for these classes to 
be subclasses of one superclass that controls for all physical aspects of the "world." Another
possibility is that one of these classes will be the superclass of the remaining classes.

The user will also have to be prompted for certain inputs, like which XML files to load, but
the need for user input will probably be scattered throughout the different classes, so we're
not sure if we will consolidate user input into a single class or not.