Deprecate XFactory.getDefault() methods and move to AtmosphereConfig

[uklance]

@jfarcand and I believe that XFactory.getDefault() methods are a bit dirty. A static method having access to non static values is an anti-pattern and requires mutable static data which I consider to be a bad idea. @jfarcand mentioned that this was legacy code that was acceptable in the bad old days of EJB < 3.

I suggest that all of the static XFactory.getDefault() methods are deprecated in favour of non static methods eg. AtmosphereConfig.getXFactory(). The preferred method is to inject the AtmosphereConfig into any services using atmosphere.

To remain backwards compatible, I guess we could store AtmosphereConfig in a static variable and the deprecated getDefault() methods could delegate through to it until they are eventually removed in a future version of atmosphere.

This means that the following will be deprecated:

AtmosphereResourceFactory.getDefault()
AtmosphereResourceSessionFactory.getDefault()
BroadcasterFactory.getDefault()
DefaultBroadcasterFactory.getDefault()
MetaBroadcaster.getDefault()
ServletContextFactory.getDefault()
ServletProxyFactory.getDefault()
WebSocketProcessorFactory.getDefault()

In favour of:

AtmosphereConfig.getAtmosphereResourceFactory()
AtmosphereConfig.getAtmosphereResourceSessionFactory()
AtmosphereConfig.getBroadcasterFactory()
AtmosphereConfig.getMetaBroadcaster()
AtmosphereConfig.getServletContextFactory()
AtmosphereConfig.getServletProxyFactory()
AtmosphereConfig.getWebSocketProcessorFactory()

[jfarcand]

Pull request welcomed. But we still need a mechanism for retrieving broadcaster from external components.

[uklance]

Yes, as I said if we have a static reference to AtmosphereConfig the deprecated static methods can pass through to it (until removed in a future major release of atmosphere).