[
https://issues.apache.org/jira/browse/TUSCANY-3013?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12707796#action_12707796
]
Mike Edwards commented on TUSCANY-3013:
---------------------------------------
This problem is caused by code in
org/apache/tuscany/sca/assembly/builder/impl/ComponentReferenceEndpointReferenceBuilderImpl.java
and by the way that the "default binding", binding.sca is handled.
During processing of a reference, a refernce with no <binding/> subelements is
given a default binding.sca for later wiring work.
However such a default binding has no attributes set (@uri and @name in
particular).
IF the <reference/> is:
- not autowired
- unwired either be means of <wire/> elements or by means of content of the
@target attribute
- and any <binding/> elements have no @uri value set
...then the code in ComponentReferenceEndpointReferenceBuilderImpl.java assumes
that the target service(s) are defined by means of binding specific
configuration (somewhere in the binding element itself)
For such cases, an endpoint is created as the target of the reference, but left
unconfigured in the expectation that the binding will fill in the details later.
However, for a <binding.sca/> the only configuration IS the @uri attribute - if
it is absent then the reference is UNWIRED - there is no target. And of
course, the default <binding.sca/> is precisely of this kind - no @uri. So in
the current code, an empty endpoint model is created, as if the details will be
filled in from the binding later, but no such details ever get created. The
result at runtime is the invocation of a wire which goes nowhere - which causes
a runtime exception.
The solution is to NOT create a wire for <binding.sca/> if there is no
autowire, @target and no @uri. This leaves the reference unwired, which may be
a problem if it is a 1..x multiplicity reference, but is just fine if it is
0..x.
ONE TWIST - the same code also gets used for handling the pseudo-references for
callbacks. These pseudo references will not have a target identified - it is
filled in later during the remainder of the callback processing.
> Java POJO with reference marked as multiplicity 0..1 is given a reference
> proxy even when the reference is unwired
> ------------------------------------------------------------------------------------------------------------------
>
> Key: TUSCANY-3013
> URL: https://issues.apache.org/jira/browse/TUSCANY-3013
> Project: Tuscany
> Issue Type: Bug
> Components: Java SCA Core Runtime
> Affects Versions: Java-SCA-2.0
> Reporter: Mike Edwards
> Assignee: Mike Edwards
> Fix For: Java-SCA-2.0
>
>
> If I have:
> o a <component/> in a composite which uses a Java POJO as its implementation,
> o that POJO has a reference, which is declared with
> @Reference(required=false), so that the reference multiplicity is 0..1
> o the <component/> leaves the <reference/> unwired (by any means)
> the current code injects a Proxy into that reference - a Proxy that is
> unwired, and which causes an exception when invoked.
> This is incorrect behaviour. An unwired 0..1 reference should cause the
> injection of null into the reference in the POJO and the POJO should be able
> to test for this null at runtime and so avoid calling the reference.
> The test which revealed this problem is the OASIS Assembly testcase
> ASM_12006_TestCase
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
