Description Zhiqiang Qian 2007-01-31 04:46:04 EST

Currrently engine provides severl built-in content type in its architecture. For extension user, normally they generate a series content objects accordinging to their special extented item structure, and Engine will collect these content, layout and send them to emitter. But since the built-in content object type is limited, the extension ability for user is also limited. For instance, they won't able to emit a circle content.

Actually the extension for IContent has two ways. 

1. allow user plug his own IContent implmentation, but this is difficult to manage and potentially cause engine layouting issue.

2. allow user attach additional info to the content object, these additional info can be recognized by particular emitter. Note this info won't change the layout behavior from engine and for those emitters which can not recognize it, still normal content behavior applied. For instance, a content object with circle info will still be treated as a rectangle object. 

So by this way, in conjunction with the report item extension and emitter extension, it makes BIRT serve as a more general design platform plus more capability.