[FELIX-2246] Lazy initialization of plugins

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: webconsole-3.0.0
• Fix Version/s: webconsole-3.1.0
• Component/s: Web Console
• Assignee: Felix Meschberger
• Reporter: Valentin Valchev
• Created: 01/Apr/10 13:27
• Updated: 19/Dec/16 17:23
• Resolved: 15/Jun/10 08:44

Description

Here at ProSyst we use a small trick to delay initialization of our services:

When the service is quite big, and loads many resources (incl. too many classes), we register not a service, but a ServiceFactory instead. With that factory we delay the instantiation of the service, when it is actually needed and obtained by other bundle.

Yes, this makes the code a little bit more complex, but it greatly improves the start-up time and the overall memory usage.

This can be applied to webconsole plugins too. My idea is that Web Console should only track Service Reference without actually obtaining the service itself [not getService()].

When the user makes request the WebConsole calls the factory to create instance. Instance is created and returned to the Web Console, which uses it to generate content for the request.

This way a plugin is actually not initialized until it is really used. Only small portion of classes, from the bundle are initialized.

Unfortunately the ServiceTracker, when notified for added service obtains the real service object. So it might be better to use directly ServiceListener for the plugins.

Issue Links

• relates to: FELIX-2410 Provide simple template service factory console plugin