TAO/docs/ORB_Internals.html

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   5     <title>TAO ORB Internals</title>
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   9     <h1>TAO ORB Internals</h1>
  10
  11     <P>This document will describe how the ORB internals work, with
  12       special attention to the areas that are more poorly documented.
  13       For example: we will not document (at least initially) the
  14       pluggable protocols framework, the interpretive marshaling
  15       engine, the POA, the waiting strategies and the
  16       leader-follower.
  17     </P>
  18     <P>New ORB developers are expected to read this document and
  19       document here all the things that they find hard to understand,
  20       surprising or event broken.
  21       New members of the ORB core team are expected to fill in details
  22       that were not explained before.
  23     </P>
  24
  25     <H3>Client Side event sequence</H3>
  26
  27     <P>In this section we will document the sequence of calls and
  28       interactions on the client side.
  29       Only the synchronous case, without forwarding or exceptions is
  30       documented at this point.
  31     </P>
  32
  33     <P>Assume the application invokes a method on an object reference,
  34       in the generated stub for that method the following sequence is
  35       started:
  36     <UL>
  37       <LI>creates TAO_GIOP_Twoway_Invocation object
  38       </LI>
  39       <LI>calls start method on the invocation object
  40       </LI>
  41
  42       <LI>TAO_GIOP_Twoway_Invocation::start:
  43         <UL>
  44           <LI>finds the profile to use for this invocation
  45           </LI>
  46           <LI>passes the profile to Connector Registry to obtain
  47             TAO_Transport object (wrapper around Service_Handler)
  48           </LI>
  49           <LI>generates and marshalls GIOP & Request headers for this
  50             invocation
  51           </LI>
  52         </UL>
  53       </LI>
  54
  55       <LI>marshalls request parameters
  56       </LI>
  57       <LI>calls invoke method on the invocation object
  58       </LI>
  59
  60       <LI>TAO_GIOP_Twoway_Invocation::invoke:
  61         <UL>
  62           <LI>sets TAO_Reply_Dispatcher (this is used to make both
  63             synch and asynch requests look the same)
  64           </LI>
  65           <LI>sends the request
  66           </LI>
  67           <LI>waits on the TAO_Wait_Strategy
  68           </LI>
  69         </UL>
  70       </LI>
  71
  72       <LI>if there was a minor problem or location forward, tries
  73             again: call TAO_GIO_Twoway_Invocation::start, etc.
  74       </LI>
  75       <LI>if everything went ok, demarshalls reply
  76       </LI>
  77     </UL>
  78   </P>
  79
  80     <hr>
  81     <address><a href="mailto:coryan@cs.wustl.edu">Carlos O'Ryan</a></address>
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