Blocker Description
Steps to reproduce:
1) Connection is closed at the socket level.
2) A user writes a message.
3) the message is encoded by a ProtocolCodecFilter.
4) MINA notices the closed socket and fires a sessionClosed event.
5) After the sessionClosed event is fired, IoFilterChain.clear() is called.
6) MINA tries to write the user write request, but the session is closed already - all write requests are discarded.
7) Before MINA discards all write requests, MINA checks if the first item in the queue is an empty buffer, which means a special separator which is handled by ProtocolCodecFilter.
8) If there's an empty buffer in the head of the queue, MINA fires a messageSent event with the empty buffer in the hope that ProtocolCodecFilter will catch it.
9) However, the filter chain is empty and therefore IoHandler implementation gets ClassCastException.
A possible workaround is just to ignore the exception, but we need to provide a correct fix for this issue.
The following is the stack trace that explains this scenario:
25151 [SocketAcceptorIoProcessor-0.4] WARN ServerPortSessionHandler -
> [/127.0.0.1:57120 <http://127.0.0.1:57120>]
> java.lang.ClassCastException:
> org.apache.mina.filter.codec.ProtocolCodecFilter$MessageByteBuffer
> incompatible with com.daishin.eai.adapter.socket.message.Por
> tMessage
> at
> com.daishin.eai.adapter.socket.handler.ServerPortSessionHandler.messageSent(ServerPortSessionHandler.java:80)
> at
> org.apache.mina.common.support.AbstractIoFilterChain$TailFilter.messageSent(AbstractIoFilterChain.java:579)
> at
> org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageSent(AbstractIoFilterChain.java:320)
> at
> org.apache.mina.common.support.AbstractIoFilterChain.access$1200(AbstractIoFilterChain.java:53)
> at
> org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.messageSent(AbstractIoFilterChain.java:653)
> at
> org.apache.mina.common.support.AbstractIoFilterChain$HeadFilter.messageSent(AbstractIoFilterChain.java:504)
> at
> org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageSent(AbstractIoFilterChain.java:320)
> at
> org.apache.mina.common.support.AbstractIoFilterChain.fireMessageSent(AbstractIoFilterChain.java:314)
> at
> org.apache.mina.transport.socket.nio.SocketIoProcessor.releaseWriteBuffers(SocketIoProcessor.java:359)
> at
> org.apache.mina.transport.socket.nio.SocketIoProcessor.doFlush(SocketIoProcessor.java:314)
> at
> org.apache.mina.transport.socket.nio.SocketIoProcessor.access$500(SocketIoProcessor.java:45)
> at
> org.apache.mina.transport.socket.nio.SocketIoProcessor$Worker.run(SocketIoProcessor.java:488)
> at
> org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:51)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:665)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:690)
> at java.lang.Thread.run(Thread.java:810)