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http://issues.apache.org/jira/browse/AXIS2-608?page=comments#action_12376550 ]
Chuck Williams commented on AXIS2-608:
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Please reopen this issue. Ajith only addressed the minOccurs=0 case, not
recursive data types.
I did not run the test as it is fairly hard for me to upgrade to a new version
of Axis2, but the issue is apparent by looking at the code. E.g., consider an
element like this:
<E>
<E>
foo
</E>
<E>
The parse() method for the outer <E> leaves the reader positioned at its own
start element when it begins to look for its properties. It then finds itself
rather than the inner <E> as the inner property!
As I wrote earlier, parsing can only be done correctly if there is a loop
invariant for the reader position. The reader needs to be at the event after
the outer element start before the property scanning begins, and then each
property needs to leave the reader at the event after its end element.
The template for the <choice> case works this way. This invariant makes both
minOccurs=0 and recursive data types straightforward.
> Generated ADB code fails on omitted scalar minOccurs=0 elements and recursive
> data types
> ----------------------------------------------------------------------------------------
>
> Key: AXIS2-608
> URL: http://issues.apache.org/jira/browse/AXIS2-608
> Project: Apache Axis 2.0 (Axis2)
> Type: Bug
> Components: databinding
> Versions: 1.0
> Environment: All
> Reporter: Chuck Williams
> Assignee: Ajith Harshana Ranabahu
> Attachments: codegen.patch
>
> The patches I submitted previously (AXIS2-523) to fix various cases of
> minOccurs=0 and recusive data types have been applied in 1.0 RC2 only for
> elements whose types are choice particles. The underlying problems remain in
> all other cases.
> One case of minOccurs=0 that fails is for an omitted scalar element
> (maxOccurs=1). Consider a simple string-valued element S, and a element C
> that contains S with minOccurs=0. The Factory.parse() method for C generates
> code to parse S that creates a SimpleElementReaderStateMachine with
> setElementNameToTest() S and then calls it. But there is no S, so the state
> machine fails.
> An example of a recusive data type problem occurs when an element E contains
> an array-valued sub-element also named E. The parser for the outer E leaves
> the reader positioned at its own start element and then proceeds to search
> for the array by scanning forward looking for the first <E>. It find itself
> and not the inner E!
> The patch resolves this issue and a set of related issues by creating a loop
> invariant for the reader position. Specifically, the reader is always after
> the end element of the prior element (or initially after the outer start
> element) when it seeks to parse an inner element. I don't believe the code
> generator can ever parse correctly without having the reader position be a
> loop invariant. This is why getElementTextProperly() is essential -- because
> getElementText() itself fails to position the reader properly in some cases
> and it is unfortunately now in commons, as documented in the comment in
> ADBBeanTemplate.xsl.
> I was able to resolve these issues by using in all cases the template that
> RC2 calls out as a special case for choice particles, i.e., by simply
> deleting the altnerative template. Perhaps there are issues with this
> template that caused it to be called out specially and used only for <choice>
> particles, but I do not know what they are. I have a complex application
> that uses all of these wsdl features and more that is working perfectly with
> this template.
> All axis2 tests pass with this template, but only after fixing a bug in one
> test that is related to the issues here (PopulateMinOccurs0Test failed when
> an omitted MinOccurs=0 parameter was actually missing).
> The attached patch against modules/codegen fixes the issues in both
> ADBBeanTemplate.xsl and PopulateMinOccurs0Test.java. This patch also
> contains the patch at AXIS-607.
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