GWT: Provider vs AsyncProvider
gwt, gwt-gin, gwtp
Solution
`Provider` is about:
- delayed instantiation (but instantiation is instantaneous, synchronous); FYI, Dagger introduces a `Lazy` type for this very use case.
- a factory of objects: unless the object is scoped, a call to `get()` will give you a new object each time
- using shorter-lived scoped objects in longer-lived scopes: if you need access to request-scoped objects from a singleton-scoped (or session-scoped) object, you have to use a `Provider`, otherwise you'll get injected an object from the current request scope, which won't be usable for the next request. GIN only supports the `Singleton` scope os it doesn't really apply here, as it's then just a variation of the above factory use case; but on the server-side (with Guice, Spring DI, Dagger, etc.), where servlets or RequestFactory services/locators are singletons (or pseudo-singletons for RF) this is a key part of the DI framework.
`AsyncProvider` is the same except it's asynchronous, wrapping a call to `GWT.runAsync()`.
In other words: only `AsyncProvider` is really about code splitting. `Provider` will have an impact on the code splitting output but no different than any factory (hand-coded, or GIN's AssistedInject).
Problem
what is the difference between provider and AsyncProvider in GWT. My understanding is that both are used for code splitting and delayed instantiation. so I am not able to decide, in which case we go for Provider and not for AsyncProvider ? Thanks in advance!