The following comment has been added to this issue:
Author: David Farb
Created: Wed, 13 Oct 2004 5:56 AM
Body:
Alan said: 'I'm not entirely comfortable with protocols calling each other
directly and much prefer an IOC type mechanism but, I'm open to discussion.'
I'm not sure exactly what you mean by that, here is specifically what I would
propose:
1. Modify the existing Protocol interface to include a 'public void fail();'
method signature.
2. Modify the existing SocketProtocol class to support the fail() method. For
example, add up.fail() to the IOException handler of serviceRead():
} catch (IOException e) {
log.trace("Communications error, closing connection: ", e);
up.fail();
close();
and apply similar modifications in other locations. close() itself does NOT
call fail(), since closing is not a failure.
3. Modify the existing classes that implement the Protocol interface with a
suitable implementation of the fail() method. The fail() method on
SocketProtocol, for example, does nothing since SocketProtocol is at the bottom
of the stack. SocketProtocol has no 'down' protocol, so there is no protocol
that could call the fail method of SocketProtocol.
In reality this is similar to the method call: 'up.sendUp(packet);' which sends
the normal, expected result from SocketProtocol to the next protocol up the
stack. 'up.fail();' simply sends an abnormal result from SocketProtocol to the
next protocol up the stack.
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View this comment:
http://issues.apache.org/jira/browse/GERONIMO-373?page=comments#action_53988
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View the issue:
http://issues.apache.org/jira/browse/GERONIMO-373
Here is an overview of the issue:
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Key: GERONIMO-373
Summary: Percolate errors from SocketProtocol up the stack
Type: Improvement
Status: Unassigned
Priority: Major
Project: Apache Geronimo
Components:
general
Assignee:
Reporter: David Farb
Created: Tue, 12 Oct 2004 9:42 AM
Updated: Wed, 13 Oct 2004 5:56 AM
Environment: All environments
Description:
o.a.g.network.protocol.SocketProtocol does not percolate a client error or
exception up the protocol stack when the client disconnects.
When serviceRead in SocketProtocol gets an IOException or some other error, the
socketChannel is closed, but the up protocol is not informed.
Calling the teardown method of the up protocol is probably not an appropriate
way to handle these exceptions. The teardown method should be called by the
creator of the protocol stack. Instead, the exception/error should percolate up
the protocol stack to the creator (via some sort of callback mechanism) which
should then remove the stack and associated information from the server
environment.
Either a new method reserved for this could be defined in the Protocol
interface (up.handleException(Throwable t)) or sending a null, empty or
specially marked packet via up.sendUp(UpPacket upPacket) could be implemented.
Since in most cases the server is waiting for a client response, if the client
goes away, server components need to be informed of this fact so the server
side objects can be cleaned up. There is usually no way to recover these
objects, hence they are a memory leak.
I would be happy to submit a fix for this, but I would appreciate feedback on
the most appropriate way to do it.
Thanks
David Farb
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