[ajug-members] Java going bonkers

[Christopher Fowler]

I'm a little confused as to when non-blocking mode is beneficial for
reading file descriptors.  In UNIX and others I rarely place a socket in
non-blocking mode.  I simply use a select() so that I know which file
descriptor can be read and then I go read that descriptor.  

If I have cleaning up stuff to do every N minutes I use the timeout
feature in the select() so that if after N seconds no descriptor is
readable I can get out of the select and go do other things.  When I'm
finished I jump back into that select.

I have processes that handle 100s of descriptors in a single thread like
this.  Is this not possible in Java?

On Wed, 2005-04-27 at 14:48, Patrick Carroll wrote:
> Take a look here:
> 
> http://www-106.ibm.com/developerworks/library/j-nioserver/
> 
> -----Original Message-----
> From: Christopher Fowler <cfowler at outpostsentinel.com>
> Sent: Apr 27, 2005 1:21 PM
> To: Ajug List <ajug-members at ajug.org>
> Subject: [ajug-members] Java going bonkers
> 
> I've got this code snippet
> 
> _newClientChannel.configureBlocking( true ) ;
> writer.writeLine( "220 SAM ENS Console Proxy" ) ;
> 
> 
> 
> 
> if( response.startsWith( "myid " ) )
> 
> If I telnet to the proxy server and after my telnet client sees the 220
> above I do a kill -9 on the client the server will loop forever on
> read()
> 
> strace shows this as fast as possible:
> 
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> [pid  2222] read(13, "", 120)           = 0
> 
> Obviously this is happening inside of
> 
> String response = reader.readLine( ) ;
> 
> How do you protect against it?
> 
> 
> 
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