SCR invokes bind method twice when dependency service properties are modified
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Key: FELIX-1841
URL: https://issues.apache.org/jira/browse/FELIX-1841
Project: Felix
Issue Type: Bug
Components: Declarative Services (SCR)
Reporter: Pierre De Rop
Priority: Minor
It seems that when a service S is depending on another service D, and when D
service properties are modified (using ServiceRegistration.setProperties
method), then D is
re-bound twice into the using service S.
For example, I have a service "Client" has a "1..1" dependency over "Service":
<?xml version="1.0" encoding="UTF-8"?>
<component name="Client">
<implementation class="client.Client"/>
<reference name="SERVICE"
interface="service.Service"
policy="dynamic"
cardinality="1..1"
target="(foo=bar)"
bind="bind"/>
</component>
public class Client {
protected void bind(Service s) {
System.out.println("Client:: bound Service : " + s);
Thread.dumpStack();
}
}
I have another bundle which provide the "Service" dependency, and sometimes,
the "Service" properties are modified like this:
ServiceRegistration reg ...
reg.setProperties(...)
So, when the setProperties takes place, "Client" is re-bound twice with the
service "Service".
Indeed, in DependencyManager, when a ServiceEvent.MODIFIED event. is caught,
the following code is invoked (line 170):
case ServiceEvent.MODIFIED:
m_componentManager.log( LogService.LOG_DEBUG, "Dependency
Manager: Updating {0}", new Object[]
{ serviceString }, null );
// remove the service first
// only continue with further event handling if the service
// removal did not cause the component to be deactivated
if ( serviceRemoved( ref ) )
{
// recalculate the number of services matching the filter
// because we don't know whether this service previously
matched
// or not
ServiceReference refs[] = getFrameworkServiceReferences();
m_size = ( refs == null ) ? 0 : refs.length;
// now try to bind the service - if it matches the target
filter
// without recalculating the size (already done).
if ( targetFilterMatch( ref ) )
{
serviceAdded( ref );
}
}
break;
So, the service is first re-bound to the Client, when the serviceRemoved()
method is invoked (it's a bound service replacement, I guess).
But the problem here is that the modified service is also re-bound, when
serviceAdded is invoked (line 189).
Don't you think that this is a bug and the service should be re-bound only
once, not twice ?
Here is the first stacktrace of the first bind:
java.lang.Exception: Stack trace
at java.lang.Thread.dumpStack(Thread.java:1158)
at client.Client.bind(Client.java:13)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at
org.apache.felix.scr.impl.helper.BaseMethod.invokeMethod(BaseMethod.java:213)
at
org.apache.felix.scr.impl.helper.BaseMethod.access$500(BaseMethod.java:38)
at
org.apache.felix.scr.impl.helper.BaseMethod$Resolved.invoke(BaseMethod.java:542)
at
org.apache.felix.scr.impl.helper.BaseMethod.invoke(BaseMethod.java:434)
at
org.apache.felix.scr.impl.manager.DependencyManager.invokeBindMethod(DependencyManager.java:948)
at
org.apache.felix.scr.impl.manager.DependencyManager.bind(DependencyManager.java:884)
at
org.apache.felix.scr.impl.manager.DependencyManager.serviceRemoved(DependencyManager.java:367)
at
org.apache.felix.scr.impl.manager.DependencyManager.serviceChanged(DependencyManager.java:177)
at
org.apache.felix.framework.util.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:878)
at
org.apache.felix.framework.util.EventDispatcher.fireEventImmediately(EventDispatcher.java:732)
at
org.apache.felix.framework.util.EventDispatcher.fireServiceEvent(EventDispatcher.java:662)
at org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:3587)
at org.apache.felix.framework.Felix.access$000(Felix.java:40)
at org.apache.felix.framework.Felix$1.serviceChanged(Felix.java:625)
at
org.apache.felix.framework.ServiceRegistry.servicePropertiesModified(ServiceRegistry.java:505)
at
org.apache.felix.framework.ServiceRegistrationImpl.setProperties(ServiceRegistrationImpl.java:116)
at service.impl.ServiceFactory.run(ServiceFactory.java:48)
at java.lang.Thread.run(Thread.java:595)
and here is the second stacktrace, when Service is re-bound:
Client: bound Service : service.impl.servicei...@142a80d
java.lang.Exception: Stack trace
at java.lang.Thread.dumpStack(Thread.java:1158)
at client.Client.bind(Client.java:13)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at
org.apache.felix.scr.impl.helper.BaseMethod.invokeMethod(BaseMethod.java:213)
at
org.apache.felix.scr.impl.helper.BaseMethod.access$500(BaseMethod.java:38)
at
org.apache.felix.scr.impl.helper.BaseMethod$Resolved.invoke(BaseMethod.java:542)
at
org.apache.felix.scr.impl.helper.BaseMethod.invoke(BaseMethod.java:434)
at
org.apache.felix.scr.impl.manager.DependencyManager.invokeBindMethod(DependencyManager.java:948)
at
org.apache.felix.scr.impl.manager.DependencyManager.serviceAdded(DependencyManager.java:271)
at
org.apache.felix.scr.impl.manager.DependencyManager.serviceChanged(DependencyManager.java:189)
at
org.apache.felix.framework.util.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:878)
at
org.apache.felix.framework.util.EventDispatcher.fireEventImmediately(EventDispatcher.java:732)
at
org.apache.felix.framework.util.EventDispatcher.fireServiceEvent(EventDispatcher.java:662)
at org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:3587)
at org.apache.felix.framework.Felix.access$000(Felix.java:40)
at org.apache.felix.framework.Felix$1.serviceChanged(Felix.java:625)
at
org.apache.felix.framework.ServiceRegistry.servicePropertiesModified(ServiceRegistry.java:505)
at
org.apache.felix.framework.ServiceRegistrationImpl.setProperties(ServiceRegistrationImpl.java:116)
at service.impl.ServiceFactory.run(ServiceFactory.java:48)
at java.lang.Thread.run(Thread.java:595)
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