The bean will receive a class instance derived from quickfix.Message and the user can do what ever he wants with this model. However, very often you may want to map the FIX representation onto your own object model. For this purpose camel-bindy is a nice tool, where you can describe how the FIX string should be mapped onto the object model.
So now we have a bit improved version of the scenario:
DataFormat bindy = ...
So, now the target bean will receive the message which is defined in your own object model.
This is the simplest scenario, but there's more to come.