Package org.jboss.weld.inject

Interface WeldInstance<T>

Type Parameters:
T - the required bean type
All Superinterfaces:
jakarta.enterprise.inject.Instance<T>, Iterable<T>, jakarta.inject.Provider<T>
All Known Implementing Classes:
AbstractCDI, ForwardingWeldInstance, InstanceImpl, SimpleCDI
public interface WeldInstance<T> extends jakarta.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:

  • Method Details

    • getHandler

      @Deprecated WeldInstance.Handler<T> getHandler()
      Deprecated.
      This method is deprecated as a similar functioning method exists in CDI 4.0 and newer. Users should instead use Instance.getHandle(). 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:
      jakarta.enterprise.inject.UnsatisfiedResolutionException - if there is no bean with given type and qualifiers
      jakarta.enterprise.inject.AmbiguousResolutionException - if there is more than one bean given type and qualifiers

    • handlers

      @Deprecated Iterable<WeldInstance.Handler<T>> handlers()
      Deprecated.
      This method is deprecated as a similar functioning method exists in CDI 4.0 and newer. Users should instead use Instance.handles(). 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

      @Deprecated default Stream<? extends WeldInstance.Handler<T>> handlersStream()
      Deprecated.
      This method is deprecated as a similar functioning method exists in CDI 4.0 and newer. Users should instead use Instance.handlesStream().
      Returns:
      a new stream of contextual reference handlers

    • getPriorityComparator

      @Deprecated Comparator<WeldInstance.Handler<?>> getPriorityComparator()
      Deprecated.
      This method is deprecated in favor of getHandlePriorityComparator() which operates on a non-deprecated Instance.Handle interface. The returned comparator sorts handlers by priority in descending order.
      • A class-based bean whose annotated type has jakarta.annotation.Priority has the priority of value jakarta.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

    • getHandlePriorityComparator

      Comparator<jakarta.enterprise.inject.Instance.Handle<?>> getHandlePriorityComparator()
      The returned comparator sorts handles by priority in descending order.
      • A class-based bean whose annotated type has jakarta.annotation.Priority has the priority of value jakarta.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 jakarta.enterprise.inject.Instance<T>

    • select

      <U extends T> WeldInstance<U> select(Class<U> subtype, Annotation... qualifiers)
      Specified by:
      select in interface jakarta.enterprise.inject.Instance<T>

    • select

      <U extends T> WeldInstance<U> select(jakarta.enterprise.util.TypeLiteral<U> subtype, Annotation... qualifiers)
      Specified by:
      select in interface jakarta.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