[Babeldoc-devel] Threading in the pipeline stage factory

[Bruce M. <br...@mc...>]

Jonathan, all:

I have been trolling around this code tonight and here are my observations:

1.  The threaded configuration on a pipeline stage.   Is this really a 
configuration option or a characteristic of the stage itself.  What I mean is 
- using this configuration, it is possible to make a potentially unthread 
safe stage run threaded.  What I propose is that those threads that can be 
run threadsafe implement the org.apache.avalon.framework.thread.ThreadSafe 
interface.  In the process results method, we then check instanceof and 
serialize if necessary.
2.  maxThreads.  Now this is definitely a configuration option for a pipeline, 
but for a particular stage?  I dont know.   What I propose is that the 
pipeline stage factory checks if this pipeline is threaded (at a pipeline 
level) and then sets up a ThreadPool (see the feeder threadpool).  In fact it 
might interesting if we look at how we abstract out the threading from the 
pipelinestagefactory altogether and then we can implement two strategies - 
basically a SynchronousPipelineProcessor and an 
AsynchronousPipelineProcessor.  Then based on whether we can run threaded or 
not, we transfer control to one or the other.   Please see the diagram.

What do you think??

regards,
Bruce.