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From Apache Wiki <wikidi...@apache.org>
Subject [Hama Wiki] Update of "StreamingProtocol" by thomasjungblut
Date Thu, 13 Sep 2012 17:29:54 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hama Wiki" for change notification.

The "StreamingProtocol" page has been changed by thomasjungblut:
http://wiki.apache.org/hama/StreamingProtocol?action=diff&rev1=2&rev2=3

  
  If you want to know how to run a user code within other environments, have a look in the
python example at the end.
  
- ==Text Based Protocol==
+ == Text Based Protocol ==
  
  The text based protocol is very easy. You have a finite amount of operations that are associated
with a unique identifier (OP_CODE). Common operations in BSP are sending a message or starting
the barrier synchronization. In Hama Streaming, every operation is ended with a newline (‘\n’)
character, so everything is done with a single line of text. Of course there are operations
that are going to use multiple lines to naturally separate information, however these are
special cases.
  
@@ -71, +71 @@

  LOG	25	Not implemented in Pipes, but in streaming it sends child logging to the Java task.
  
  
- ==Acknowledgements==
+ == Acknowledgements ==
  
  To detect whether the forked child has arrived at the next stage of an algorithm, we work
with acknowledgements (short ACK), that have a special formatting. 
  ACKS are formally expressed as "%ACK_" + OP_CODE + "%=", where OP_CODE is the operation
to acknowledge.
  
- ==Initialization Sequence==
+ == Initialization Sequence ==
  
  After the child process has been forked from the Java BSP Task, a special initialization
sequence is needed. Formally the sequence looks like this:
  
@@ -124, +124 @@

  
  The three steps are called in sequential order, so after you have ACK’d the end of the
setup, the Java code will immediately start telling you about that you need to start the bsp
function. This applies also for the transition between bsp and cleanup function.
  
- ==BSPPeer Functionality==
+ == BSPPeer Functionality ==
  
  People familiar with the Hama BSP API know that there is a context object which gives access
to the BSP functionality like send or sync. We think this is a cool design and you should
take care of implementing it as well, so you can pass this peer in all the user implemented
functions. 
  
@@ -150, +150 @@

  readKeyValue	-	%6%=	Key and Value in two separate following lines. If no input available,
both are equal to “%%-1%%”.
  reopenInput	-	%17%=	
  
- ==Closing Sequences==
+ == Closing Sequences ==
  
  To determine if the child process successfully finished its computations, we have a closing
sequence that is expected after you acknowledged your cleanup.
  The closing sequence is basically just sending TASK_DONE and DONE command to the Java process.
@@ -165, +165 @@

  Congratulation, you are now able to implement Hama streaming in other languages.
  
  
- =Appendix=
+ = Appendix =
  
- ==Known implementations==
+ == Known implementations ==
  
   * Hama Streaming for Python: https://github.com/thomasjungblut/HamaStreaming
  
  
- ==Running user code in the Python environment==
+ == Running user code in the Python environment ==
  
  In the Python runtime, you can pass a .py filename to the BSPRunner as argument, using __import__
you can import the class, get the class via getattr and get an instance by instantiating this
class.
  

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