[xSocket-develop] How to handle this situation in an onData Handler

[Thomas S. <ts...@ib...>]

Hello,

I'm using xSocket 1.2.1 and I'm really happy how easy it is to use the 
Non-Blocking stuff, although I run into the following implementation 
problem.

Basically, I have the following onData handler (sorry for the formatting):


public boolean onData(INonBlockingConnection con) throws IOException, 
BufferUnderflowException {
		
EODProtocolContentHandler ch = (EODProtocolContentHandler) 
con.getAttachment();
		
        if (ch != null) {
             return ch.onData(con);
         }

         con.resetToReadMark();
         con.markReadPosition();

         String macAddress = 
con.readStringByDelimiter(MCIProtocolConsts.NEWLINE);
         String checksum = 
con.readStringByDelimiter(MCIProtocolConsts.NEWLINE);
         String payLoadLength = 
con.readStringByDelimiter(MCIProtocolConsts.NEWLINE);

         con.removeReadMark();
         // At this point, the header has been read!

         // Proceed with reading the payload
         ch = new EODProtocolContentHandler(
         		con.getRemoteAddress().getHostName()
         		, macAddress
         		, checksum
         		, Integer.valueOf(payLoadLength).intValue());

         con.setAttachment(ch);
         ch.onData(con);


         // Proceed with handling the parameter upload
	// missing code here ...

	return true;
}


This code works fine. It reads a few lines from the socket and then some 
kind of payload (compressed XML stream) via a particular content handler.

 From the comment "// Proceed with handling the parameter upload on", I 
would like to do the following:

1) Writing something back to the client
2) Reading a return code sent by the client


ad 1): works fine by using the con.write method. I'm able to transfer a 
few lines and another compressed XML stream to the client.

ad 2): reading the return code although does not work. I'm always 
running into the a BufferUnderflowException exception when doing the 
following:

con.readStringByDelimiter(MCIProtocolConsts.NEWLINE)


Using the con.markReadPosition ... concepts at this position for reading 
the return code from the client doesn't work either, because with the 
con.resetToReadMark() at the BEGINNING of the onData handler, it thinks 
there should be three lines ...


Any hints are much appreciated!

Thanks,
Thomas