Package org.int4.dirk.spi.instantiation

Interface InjectionTargetExtension<T,E>

Type Parameters:

T - the type handled

E - the element type required

All Known Implementing Classes:

InstanceInjectionTargetExtension, ListInjectionTargetExtension, ProviderInjectionTargetExtension, SetInjectionTargetExtension

public interface InjectionTargetExtension<T,E>

An interface to allow for custom handling of injection targets of type T. The target class must be an interface with at least one type variable.

Whenever an injection target of type T needs injection this extension will be called to provide the actual value.

Method Summary

Modifier and Type	Method	Description
java.lang.reflect.Type	getElementType(java.lang.reflect.Type type)	Returns the element type of the given type by unwrapping the given type.
T	getInstance(InstantiationContext<E> context)	Creates an instance of type T using the given InstantiationContext.
java.lang.Class<?>	getTargetClass()	Returns the target class extended by this extension.
java.util.Set<TypeTrait>	getTypeTraits()	Returns the TypeTraits of this extension.

Method Detail

getTargetClass

java.lang.Class<?> getTargetClass()

Returns the target class extended by this extension.

Returns:

a Class, never null

getElementType

java.lang.reflect.Type getElementType(java.lang.reflect.Type type)

Returns the element type of the given type by unwrapping the given type. Returning null or the same type is not allowed.

Parameters:

type - a Type to unwrap, cannot be null

Returns:

the element type of the given type by unwrapping the given type, never null

getTypeTraits

java.util.Set<TypeTrait> getTypeTraits()

Returns the TypeTraits of this extension.

Returns:

a set of TypeTrait, never null or contains null, but can be empty

getInstance

T getInstance(InstantiationContext<E> context)
       throws CreationException,
              AmbiguousResolutionException,
              UnsatisfiedResolutionException,
              ScopeNotActiveException

Creates an instance of type T using the given InstantiationContext. Returning null is allowed to indicate the absence of a value. Depending on the destination where the value is used this can mean null is injected (methods and constructors), that the value is not injected (fields) or that an UnsatisfiedResolutionException is thrown (direct instance resolver call).

Parameters:

context - an InstantiationContext, cannot be null

Returns:

an instance of type T, can be null

Throws:

CreationException - when the instance could not be created

AmbiguousResolutionException - when multiple instances matched but at most one was required

UnsatisfiedResolutionException - when no instance matched but at least one was required

ScopeNotActiveException - when the scope for the produced type is not active