Re: [xSocket-develop] ClosedChannelException

[David A. <da...@st...>]

Hi

	Thanks for your insight Gregor.
	Indeed I was wodering why the readStringByDelimiter was returning a  
bytebuffer[] since in every case I tested the array only seemed to  
contain one element. I'll update my code as you sugest regarding this,  
and regarding the data serialization issue.
	But, correct me if I'm mistaken, that doesn't explain why the client  
always throws a ClosedChannelException after 67 object serializations,  
right?
	Any ideas as to why this is happening?

Regards
David Alves

On Nov 5, 2008, at 7:08 AM, Gregor Roth wrote:

> Hi David,
>
> the <connection>.readByteBufferByDelimiter(…) returns an array of  
> byte buffers. This doesn't mean, that several records (separated by  
> a delimiter) is fetched. If you get an array longer than 1, it just  
> means that more than one byte buffer is used to hold the record  
> data. This is caused by a fragmented network I/O read. For  
> performance reasons xSocket doesn't merge such fragmented byte  
> buffers into a single buffer. xSocket's DataConverter class supports  
> a toByteBuffer(ByteBuffer[] buffers) method to do this (which has  
> performance impacts).
>
> In your code you have also to ensure that your delimiter will never  
> appear as part of the serialized data. May be using a leading length  
> filed would be a better approach
>
> Gregor
>
>
>
>
> 2008/11/5 David Alves <da...@st...>
> Hi
>
> 	I'm trying xsocket for the first time and I quite like the api and  
> the features.
> 	I'm using a nonblockingpipeline over a multiplexed connection and  
> all seems fine, until the channel closes and a  
> ClosedChannelException is thrown.
> 	I'm reasearching some event processing mechanisms and as such I  
> serialize objects across the client to the server, and it all boils  
> down to the fact that I always can send 67 and just 67 events.
> 	Strange no?
> 	Any help would be greatly appreciated.
> 	My send/receive code along with the trace is in the end of the email.
>
> Kind regards
> David Alves
> 	
> ______________________
>
> 	Client: (All the connection creation code is done only once then a  
> generating thread tries to send event through the pipeline)
> 	
> 	Creation:
> 		this.nativeConnection = new NonBlockingConnection(this.host, port,  
> Integer.MAX_VALUE);
> 	this.multiplexedConnection = new  
> MultiplexedConnection(nativeConnection);
> 	controlPipelineId = multiplexedConnection.createPipeline();
> 	controlPipeline =  
> multiplexedConnection.getNonBlockingPipeline(controlPipelineId);
>
> 	Repeat:
> 	FastByteArrayOutputStream fbaos = new FastByteArrayOutputStream();
> 	ObjectOutputStream oos = new ObjectOutputStream(fbaos);
> 	oos.writeObject(event);
> 	ByteBuffer objectBuffer = fbaos.getByteBuffer();
> 	controlPipeline.write(objectBuffer);
> 	controlPipeline.write(EVENT_SEPARATOR);
>
> ________________
>
>    Server: (Implements IPipelineDataHandler)
> 	ByteBuffer[] eventsBbs = pipeline
> 					.readByteBufferByDelimiter 
> (DummyMultiplexedNonBockingAdapter.EVENT_SEPARATOR);
> 	for (ByteBuffer eventBb : eventsBbs) {
> 		FastByteArrayInputStream fbais = new  
> FastByteArrayInputStream(eventBb);
> 		ObjectInputStream ois = new ObjectInputStream(fbais);
> 		Event event;
> 		try {
> 			event = (Event) ois.readObject();
> 		} catch (ClassNotFoundException e) {
> 			throw new IOException(e);
> 		}
> 		receiveEvent(event);
> 	}
>
> Trace:
>
> Caused by: java.nio.channels.ClosedChannelException
> 	at  
> org 
> .xsocket 
> .connection 
> .AbstractNonBlockingStream 
> .ensureStreamIsOpenAndWritable(AbstractNonBlockingStream.java:1472)
> 	at  
> org 
> .xsocket 
> .connection 
> .AbstractNonBlockingStream.write(AbstractNonBlockingStream.java:1140)
> 	at  
> pt 
> .uc 
> .dei 
> .fincos 
> .adapter 
> .dummy 
> .remote 
> .DummyMultiplexedNonBockingAdapter 
> .send(DummyMultiplexedNonBockingAdapter.java:72)
> 	... 19 more
> java.lang.NullPointerException
> 	at  
> pt 
> .uc 
> .dei 
> .fincos 
> .adapter 
> .dummy 
> .remote 
> .DummyMultiplexedNonBockingAdapter 
> .send(DummyMultiplexedNonBockingAdapter.java:72)
>
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