Package com.google.inject.multibindings

Interface OptionalBinderBinding<T>

Type Parameters:

T - The fully qualified type of the optional binding, including Optional. For example: Optional<String>.

public interface OptionalBinderBinding<T>

A binding for a OptionalBinder.

Although OptionalBinders may be injected through a variety of types V, Optional<V>, Optional<Provider<V>>, etc..), an OptionalBinderBinding exists only on the Binding associated with the Optional<V> key. Injectable types can be discovered using getKey() (which will return the Optional<V> key), orgetAlternateKeys() (which will return the other keys that can inject this data). Other bindings can be validated to be derived from this OptionalBinderBinding using containsElement(com.google.inject.spi.Element).

Since:

4.0

Method Summary

Modifier and Type	Method	Description
boolean	containsElement(Element element)	Returns true if this OptionalBinder contains the given Element in order to build the optional binding or uses the given Element in order to support building and injecting its data.
Binding<?>	getActualBinding()	Returns the actual binding (set by OptionalBinder.setBinding()) or null if not set.
Set<Key<?>>	getAlternateKeys()	Returns the keys of other bindings that represent this OptionalBinder.
Binding<?>	getDefaultBinding()	Returns the default binding (set by OptionalBinder.setDefault()) if one exists or null if no default binding is set.
Key<T>	getKey()	Returns the Key for this binding.

Method Detail

getKey

Key<T> getKey()

Returns the Key for this binding.

getAlternateKeys

Set<Key<?>> getAlternateKeys()

Returns the keys of other bindings that represent this OptionalBinder. This will return an entry for Optional<com.google.inject.Provider<V>> and Optional<javax.inject.Provider<V>>.

Since:

4.2.3

getDefaultBinding

Binding<?> getDefaultBinding()

Returns the default binding (set by OptionalBinder.setDefault()) if one exists or null if no default binding is set. This will throw UnsupportedOperationException if it is called on an element retrieved from Elements.getElements(com.google.inject.Module...).

The Binding's type will always match the type Optional's generic type. For example, if getKey returns a key of Optional<String>, then this will always return a Binding<String>.

getActualBinding

Binding<?> getActualBinding()

Returns the actual binding (set by OptionalBinder.setBinding()) or null if not set. This will throw UnsupportedOperationException if it is called on an element retrieved from Elements.getElements(com.google.inject.Module...).

The Binding's type will always match the type Optional's generic type. For example, if getKey returns a key of Optional<String>, then this will always return a Binding<String>.

containsElement

boolean containsElement(Element element)

Returns true if this OptionalBinder contains the given Element in order to build the optional binding or uses the given Element in order to support building and injecting its data. This will work for OptionalBinderBinding retrieved from an injector and Elements.getElements(com.google.inject.Module...). Usually this is only necessary if you are working with elements retrieved from modules (without an Injector), otherwise getDefaultBinding() and getActualBinding() are better options.