Package javax.inject
Interface Provider<T>
- All Known Subinterfaces:
Instance<T>
- All Known Implementing Classes:
CDI
public interface Provider<T>
Provides instances of
T
. Typically implemented by an injector. For
any type T
that can be injected, you can also inject
Provider<T>
. Compared to injecting T
directly, injecting
Provider<T>
enables:
- retrieving multiple instances.
- lazy or optional retrieval of an instance.
- breaking circular dependencies.
- abstracting scope so you can look up an instance in a smaller scope from an instance in a containing scope.
For example:
class Car { @Inject Car(Provider<Seat> seatProvider) { Seat driver = seatProvider.get(); Seat passenger = seatProvider.get(); ... } }
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Method Summary
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Method Details
-
get
T get()Provides a fully-constructed and injected instance ofT
.- Throws:
RuntimeException
- if the injector encounters an error while providing an instance. For example, if an injectable member onT
throws an exception, the injector may wrap the exception and throw it to the caller ofget()
. Callers should not try to handle such exceptions as the behavior may vary across injector implementations and even different configurations of the same injector.
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