Package org.jboss.weld.inject

Interface WeldInstance<T>

Type Parameters:

T - the required bean type

All Superinterfaces:

javax.enterprise.inject.Instance<T>, Iterable<T>, javax.inject.Provider<T>

public interface WeldInstance<T>
extends javax.enterprise.inject.Instance<T>

Represents an enhanced version of Instance.

In the following example we filter out beans which are not Dependent then sort the beans by priority and use the handler whose bean has the highest priority (according to getPriorityComparator()) to obtain the hello string. Note that contextual references for beans with lower priority are not created at all.

 @ApplicationScoped
 class Hello {

     @Inject
     WeldInstance<HelloProvider> instance;

     String hello() {
         HelloProvider helloProvider = instance.handlersStream().filter(h -> h.getBean().getScope().equals(Dependent.class))
                 .sorted(instance.getPriorityComparator()).findFirst().map(Handler::get).orElse(null);
         if (helloProvider != null)
             return helloProvider.getHello();
         return "No hello provider found!";
     }
 }
 

Author:

Martin Kouba

See Also:

WELD-2204

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	WeldInstance.Handler<T>	This interface represents a contextual reference handler.

Method Summary

Modifier and Type	Method	Description
WeldInstance.Handler<T>	getHandler()	Obtains an initialized contextual reference handler for the bean that has the required type and required qualifiers and is eligible for injection.
Comparator<WeldInstance.Handler<?>>	getPriorityComparator()	The returned comparator sorts handlers by priority in descending order.
Iterable<WeldInstance.Handler<T>>	handlers()	Allows to iterate over contextual reference handlers for all the beans that have the required type and required qualifiers and are eligible for injection.
default Stream<WeldInstance.Handler<T>>	handlersStream()
WeldInstance<T>	select(Annotation... qualifiers)
<U extends T> WeldInstance<U>	select(Class<U> subtype, Annotation... qualifiers)
<X> WeldInstance<X>	select(Type subtype, Annotation... qualifiers)	Obtains a child Instance for the given required type and additional required qualifiers.
<U extends T> WeldInstance<U>	select(javax.enterprise.util.TypeLiteral<U> subtype, Annotation... qualifiers)

Methods inherited from interface javax.enterprise.inject.Instance

destroy, isAmbiguous, isResolvable, isUnsatisfied, stream

Methods inherited from interface java.lang.Iterable

forEach, iterator, spliterator

Methods inherited from interface javax.inject.Provider

get

Method Detail

getHandler

WeldInstance.Handler<T> getHandler()

Obtains an initialized contextual reference handler for the bean that has the required type and required qualifiers and is eligible for injection.

The contextual reference is obtained lazily, i.e. when first needed.

Returns:

a new handler

Throws:

javax.enterprise.inject.UnsatisfiedResolutionException - if there is no bean with given type and qualifiers

javax.enterprise.inject.AmbiguousResolutionException - if there is more than one bean with given type and qualifiers

handlers

Iterable<WeldInstance.Handler<T>> handlers()

Allows to iterate over contextual reference handlers for all the beans that have the required type and required qualifiers and are eligible for injection.

Note that the returned Iterable is stateless and so each Iterable.iterator() produces a new set of handlers.

Returns:

a new iterable

handlersStream

default Stream<WeldInstance.Handler<T>> handlersStream()

Returns:

a new stream of contextual reference handlers

getPriorityComparator

Comparator<WeldInstance.Handler<?>> getPriorityComparator()

The returned comparator sorts handlers by priority in descending order.

• A class-based bean whose annotated type has javax.annotation.Priority has the priority of value javax.annotation.Priority#value()
• A custom bean which implements Prioritized has the priority of value Prioritized.getPriority()
• Any other bean has the priority of value 0

Returns:

a comparator instance

select

WeldInstance<T> select(Annotation... qualifiers)

Specified by:

select in interface javax.enterprise.inject.Instance<T>

select

<U extends T> WeldInstance<U> select(Class<U> subtype,
                                     Annotation... qualifiers)

Specified by:

select in interface javax.enterprise.inject.Instance<T>

select

<U extends T> WeldInstance<U> select(javax.enterprise.util.TypeLiteral<U> subtype,
                                     Annotation... qualifiers)

Specified by:

select in interface javax.enterprise.inject.Instance<T>

select

<X> WeldInstance<X> select(Type subtype,
                           Annotation... qualifiers)

Obtains a child Instance for the given required type and additional required qualifiers. Must be invoked on Instance<T> where T is Object.

Type Parameters:

X - the required type

Parameters:

subtype - a Type representing the required type

qualifiers - the additional required qualifiers

Returns:

the child Instance

Throws:

IllegalArgumentException - if passed two instances of the same non repeating qualifier type, or an instance of an annotation that is not a qualifier type

IllegalStateException - if the container is already shutdown

IllegalStateException - if invoked on Instance<T> where T is of any other type than Object