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Posted to dev@aries.apache.org by "Jeremy Hughes (JIRA)" <ji...@apache.org> on 2014/09/12 13:09:34 UTC

[jira] [Resolved] (ARIES-1201) Blueprint start can hang when using reference-listeners

     [ https://issues.apache.org/jira/browse/ARIES-1201?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jeremy Hughes resolved ARIES-1201.
----------------------------------
    Resolution: Fixed

Applied fix in this revision: http://svn.apache.org/viewvc?view=revision&revision=1624496

> Blueprint start can hang when using reference-listeners
> -------------------------------------------------------
>
>                 Key: ARIES-1201
>                 URL: https://issues.apache.org/jira/browse/ARIES-1201
>             Project: Aries
>          Issue Type: Bug
>          Components: Blueprint
>            Reporter: Simon Gormley
>            Assignee: Jeremy Hughes
>         Attachments: BlueprintStartOrder.diff
>
>
> Blueprint startup can hang if a reference listener uses the same bean as it is tracking.
> For the blueprints included below, blueprints 1 and 2 start processing on different threads. Blueprint 2 tries to get the service from blueprint 1, but blocks as blueprint 1's bean is waiting for the reference to become available. Blueprint 1 runs, tries to create the reference, and so needs to create the bean, but can't as blueprint 2 has started this, and so blueprint 1 can't complete to release blueprint 2.
> Essentially, this happens as the blueprint service is registered before it is completely ready to be used. If the eager components were created before registering, the service would be ready to be used straight away. Section 121.6 of the OSGi spec indicates that a blueprint service shouldn't be registered before it is ready.
> Blueprint 1:
> <reference id="i" interface="api.Interface">
>   <reference-listener ref="AImplBeanBean" unbind-method="unbound"/>
> </reference>
> <bean id="AImplBeanBean" class="bundle2.AImplBean" init-method="init">
>   <property name="i" ref="i"/>
> </bean>
> <service id="ASrv" ref="AImplBeanBean" interface="api.InterfaceA" activation="eager"></service>
> Blueprint 2:
> <bean id="BImplBeanBean" class="bundle3.BImplBean"
>  init-method="init" activation="lazy">
>   <property name="a" ref="A"/>
> </bean>
> <service id="BImplBeanBeanService" ref="BImplBeanBean"
>   interface="api.InterfaceB" />
> <reference interface="api.InterfaceA" id="A"/>
> Blueprint 3:
> <blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" default-activation="lazy">
> <bean id="InterfaceImplBean" class="pmr40452.impl.InterfaceImpl" />
> <service id="Impl" ref="InterfaceImplBean"
>   interface="api.Interface" />
> </blueprint>



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