On 10.03.2010, at 09:46, Ceki Gülcü wrote:
The end result is very similar to asking your StructuredDataMessage in the org.slf4j.message package for its formatted message, except that the question is asked by a RFC5424Encoder. A different encoder would ask a different question.
This is not similar at all. The layout/encoder/whatever calls getFormattedMessage and gets an appropriate response. Since everything is a Message the method is always there.
How is this different than toString()? Everything is an object and the toString() method is always there.
Well, the idea was the following: I didn't want to allow just any type of Object - which would be possible if we'd simply use toString(). I wanted to emphasize the use of Messages of certain types instead of simply dumping just any Object into the Logger. Message.getFormattedMessage() is supposed to return a lazily initialized and cached String representation of the message. (I'm not sure if this has been documented yet. Chances are good that it isn't) toString(), on the other hand, can still be used for debugging output of a Message. toString() is generated code (by Eclipse or IDEA) most of the time. Even if that isn't the case, I dare say that it's caching it's result very seldom. I'm only talking about the typical implementation here. Since multiple appenders might use the formatted message of the same event, caching might make a rather big difference. It's just a semantic difference and an attempt to push the user in a certain direction (i.e. "Take a look at Messages!"). This semantic difference should be documented in the Message interface, obviously. Cheers, Joern.