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From "R J Scheuerle Jr" <>
Subject Re: Concurrency problems (Attn: Rich)
Date Wed, 01 May 2002 20:34:17 GMT
Yes you are correct.

The SimpleDeserializers could be shared per thread.  Deserializers for
multi-ref'd things cannot be shared at all.

Rich Scheuerle
XML & Web Services Development
512-838-5115  (IBM TL 678-5115)

                      Glen Daniels                                                       
                      <gdaniels@macrome        To:       "'Axis-Dev (E-mail)'" <>
            >                 cc:                                    
                                               Subject:  Concurrency problems (Attn: Rich)
                      05/01/2002 03:22                                                   
                      Please respond to                                                  

I isolated the concurrency failures to two places.  First,
SAXParserFactories are not guaranteed to be thread-safe, so I synchronized
the saxFactory.newSAXParser() call.

Second, and much more major - we are apparently "sharing" instances of
SimpleDeserializers....?!?  I don't understand how this could work in a
multi-threaded environment, when each deserializer is maintaining a
StringBuffer collecting values from deserialized XML....

I propose we remove all of the code related to sharing deserializers.
Serializers may be shared, since they don't have state, but Deserializers
must be created on a per-instance basis, or must be redesigned to hold
state in TLS or some other thread-safe place.  I may be missing something
here, so please fill me in if you think this is an incorrect analysis.  I
will note that turning off sharing in all cases has fixed the concurrency
test problems.

Sorry for not noticing and commenting on this earlier.


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