How do visual programming tools like JBuilder, Visual Cafe, VisualAge
use design patterns to interract with the javabeans components one
adds to the "canvas". I am aware of the details of how javabeans work
but I am looking for more of how the tool might use this information.

Already, I can see the following patterns possibly being used by
visual development tools.


1. Observer Pattern so that other beans register to be update when one
bean is moved/updated.

2. Strategy if you have several bean implementation with varying
algorithms that you need to swap given the appropriate context.

3. Factory creating beans of a given supertype

4. Facade pattern....given a complex bean infrastructure,you want to
encapsulate the complexity and allow clients easy access without
knowledge of the underlying implementation

5. Composite pattern to group beans when a "group" button is pressed
during construction phase

How do these tools realise these patterns with respective to visual
development. I am very much interested of you could provide some low
level detail on these or any other I've missed. Alternatively, you
could point me to resources(free internet resources preferably) I
could research on.