[RT] Flyweight for Cocoon?

[Berin Loritsch]

One of the problems identified in Cocoon is the use of a great number of 
pooled components.  The complaint being that Cocoon is pooled to death. 
 Something that I ran into with a Swing based app that surprised me was 
the difference between reusing a JComponent object and changing its 
parameters vs creating a new one for each cell in a table.  The thing is 
that reusing that component resulted in a tremendous performance gain 
(20x).  Something to realize here is that the Flyweight pattern IS NOT 
POOLING.  You have a set of objects that have the most expensive part 
already done, and you reuse those objects reconfiguring as needed.

It got me to thinking if this could be done for Cocoon with similar 
results.  The part that might make it more difficult is the transformer. 
  Perhaps if we used the ThreadLocal object to keep the max number of 
transformers that would would need to use for any one thread and then 
configured them by reusing those instances we could cut down on the 
number of transformers/generators/serializers needed.

The per-thread approach would work as long as there is a guarantee of 
one thread per request--which seems to be valid for the current crop of 
servlet engines.