[FELIX-2288] Felix SCR API problem/misunderstanding

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: scr-1.0.0, scr-1.0.2, scr-1.0.4, scr-1.0.6, scr-1.0.8, scr-1.2.0, scr-1.4.0, webconsole-3.1.0
• Fix Version/s: scr-1.6.0, webconsole-3.1.2
• Component/s: Declarative Services (SCR), Web Console
• Assignee: Felix Meschberger
• Reporter: Valentin Valchev
• Created: 16/Apr/10 07:25
• Updated: 16/Aug/10 12:11
• Resolved: 03/Aug/10 10:25

Description

I've been playing with the Components plugin of the Web Console and it work perfectly with the Felix SCR implementation. When I switched to ProSyst/Equinox implementation (they are basically the same) I found a small problem.

When I disable a component, it's ID becomes -1 and I cannot enable it anymore. As long as I disable components all their IDs becomes -1.

I opened the OSGi r4.2 specification to see if there is a reason for this behaviour. The JavaDoc for ComponentConstants states for the component ID, that
"The value of this property is assigned by the Service Component Runtime when a component configuration is created."

In part 112.6 Component Properties, the specification says, that 'component.id' property is always added by the SCR but for "Each component configuration".

When a component is disabled or uninstalled, there is no configuration - it's just a component definition. So the SCR is not required to assign ID.

As for the Web Console we can easily fix the problem by using the pair bundle + component name for identification, instead of ID. However, since Apache SCR API is becoming recommended OSGi API, it would be better to define a mature and compatible API.