io.micronaut.context

Interface Qualifier<T>

Type Parameters:

T - The qualifier type

All Known Implementing Classes:

AnyQualifier, ClosestTypeArgumentQualifier, ConsumesMediaTypeQualifier, InterceptorBindingQualifier, ProducesMediaTypeQualifier, TypeAnnotationQualifier, TypeArgumentQualifier

public interface Qualifier<T>

Used to qualify which bean to select in the case of multiple possible options.

NOTE: When implementing a custom Qualifier you MUST implement Object.hashCode() and Object.equals(Object) so that the qualifier can be used in comparisons and equality checks

Since:

1.0

Author:

Graeme Rocher

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	PRIMARY The name of the primary annotation class.

Method Summary

Modifier and Type	Method and Description
default boolean	contains(Qualifier<T> qualifier) Whether this qualifier contains the given qualifier.
default <BT extends BeanType<T>> java.util.Optional<BT>	qualify(java.lang.Class<T> beanType, java.util.stream.Stream<BT> candidates) Qualify the candidate from the stream of candidates.
<BT extends BeanType<T>> java.util.stream.Stream<BT>	reduce(java.lang.Class<T> beanType, java.util.stream.Stream<BT> candidates)

Field Detail

PRIMARY

static final java.lang.String PRIMARY

The name of the primary annotation class.

Method Detail

reduce

<BT extends BeanType<T>> java.util.stream.Stream<BT> reduce(java.lang.Class<T> beanType,
                                                            java.util.stream.Stream<BT> candidates)

Type Parameters:

BT - The bean type subclass

Parameters:

beanType - The bean type

candidates - The candidates

Returns:

The qualified candidate or null it it cannot be qualified

contains

default boolean contains(Qualifier<T> qualifier)

Whether this qualifier contains the given qualifier.

Parameters:

qualifier - The qualifier

Returns:

True it does

qualify

default <BT extends BeanType<T>> java.util.Optional<BT> qualify(java.lang.Class<T> beanType,
                                                                java.util.stream.Stream<BT> candidates)

Qualify the candidate from the stream of candidates.

Type Parameters:

BT - The bean type subclass

Parameters:

beanType - The bean type

candidates - The candidates

Returns:

The qualified candidate or Optional.empty()