I'm running into a bug in a Mina(2.0M4)-based server I'm developing that
seems to be due to the implementation of CumulativeProtocolDecoder.
Reading through the code, it appears that CumulativeProtocolDecoder
executes a different code path when I'm unit testing with a DummySession
vs. when I'm running on a live server with a real session. When using a
DummySession, it looks like it completely ignores all the functionality
for accumulating messages across decode invocations - i.e., never
empties out the remaining contents of the in buffer (to be stored in the
session for next invocation) and also ignores the true or false return
value that my decoder returns from the doDecode method. i.e.:
if (!session.getTransportMetadata().hasFragmentation()) {
doDecode(session, in, out);
return;
}
vs.
boolean decoded = doDecode(session, buf, out);
if (decoded) {
...
} else {
break;
}
This is causing a big problem in my testing code. I'm trying to test
that I'm properly handling various situations where the remote user
makes a call to the server with erroneous and/or missing data. In these
cases, I'm returning "false" from the doDecode method, attempting to
indicate to the CumulativeProtocolDecoder parent class that there's not
enough data to decode the message.
However, the ProtocolCodeFilter calls the CumulativeProtocolDecoder's
decode method in a loop as follows:
while (in.hasRemaining()) {
...
decoder.decode(session, in, decoderOut);
}
And since the CumulativeProtocolDecoder never empties the in buffer when
using a DummySession, the net result is that my test is going into an
infinite loop.
Seems to me the workaround I'd need to put in place to get around this
would be rather ugly. I'd need to code my CumulativeProtocolDecoder
subclass in such a way that it's aware of whether it's being called from
a DummySession or not (i.e.,
!session.getTransportMetadata().hasFragmentation()). When fragmentation
is in effect, it'd be OK to return false (need more data). But when
it's not in effect, then I'd need to invoke different code to flag the
insufficient data condition as erroneous data.
So I'm wondering a few things:
* Should this implementation of CumulativeProtocolDecoder be considered
buggy (in that it causes different behavior when using DummySessions)?
* Is there any reason why the CumulativeProtocolDecoder needs to handle
the dummy (non-fragmentable) session differently? Would it not be
possible to have a single set of code that works identically for both?
* If this isn't considered a bug, then is there any cleaner way for me
to work around this situation?
TIA,
DR
