Definition of a property.  A property is an adjustable parameter of an object.  A property may be read-only and used to peek
at the status of an object.  A property may be another object.  A property may be an array of objects.  This is all beany.

1. Attributes of Properties.
  1. Security model
     1.  that allows us to restrict which properties may be adjusted by the end-user.
     2.  that allows us to restrict the properties which may be stored persistently.
  2. Properties should be editable and serializable "for free," meaning that no effort is required to get these features for new objects.
  3. Properties of new objects should be discovered in a reasonable and safe way.

2. Example uses.
   1. application development
      1. layout, labels, colorbar, etc are set interactively by the application developer.
      2. satisfied, the developer releases the application, but limiting adjustable properties to the time axis range.
   2. non-persistent properties
      1. the developer wishes to add a new parameter for testing which is used interactively 
      2. this parameter should not be serialized to persistent storage, however, since its meaning may change.

3. discovery of properties.
   1. a "BeanInfo" object for the object class identifies the properties explicitly
   2. or the java beans convention for getX/setX is used to identify implicit properties.

4. Access Levels--not implemented
   1. ALL -- the property may be adjusted freely, no restrictions
   2. DEVELOPER -- adjustable by the application developer  ( This is the default for implicit properties. )
   3. END_USER -- adjustable by the end-user.

5. Persistence.
   1. none -- the property should never be used as a part of the state.  Including within session.
   2. transient -- the property is only persistent on a per-session basis.  For example, undo/redo should include this.
   3. persistent -- the property may be serialized and stored.

6. Arbitary xml to application
   1. bean requirements
      1. no-argument constructor
      2. properties adjusted in any order--this is a bean requirement because of property editor as well.
      3. must be named
   2. update messages
      1. propertyChanged messages used to implement bean inter-dependence.
      2. "listens to" notation needed.
      3. message-coalescing mechanism needs to be preserved.
   3. missing objects 
      1. some sort of canvas layout manager that manages rows