Component Lifecycle

With "Jacson Component" we mean the plugin classes, namely JacsonChunkSource, JacsonFilter, JacsonEvaluator,

These components are (essentially) all used in a similar fashion:

1. They are constructed by a generic factory FastClassForName
2. Later they get initialized by a call to their two argument init() method.
3. Further configuration is left over to the component by inspection of its ConfigNode and its JacsonRegistry. Note: This is "pull" configuration, like in suns servlet spec, the alternative would have been a "beany" "push" configuration like Ants and many other tools have. Both has advantages and disadvantages.
4. To finish setup the registerState() and registerReport() are called.
5. Next step somewhat depend on the actual class:
   • JacsonChunkSource:
     1. message() is called once.
     2. nextChunk() is called arbitrarily often until a null is returned.
   • JacsonFilter:
     1. setDrain() is called once.
     2. putChunk() is called often.
   • JacsonEvaluator is like JacsonFilter, only there is no setDrain() call.
6. For all plugins once and finally a summary() is issued.

Remarks:JacsonReport is somewhat different, since the top most report might be set by application and not by the xml configuration. Therefore the init() method does not have the second JacsonRegistry argument, since a surrounding application will not have such a Registry. A report might also have a constructor with arguments. But if it only has such an constructor it cannot be used within configuration files. On the other hand it is not entirely different.