Package org.springframework.beans.factory

Interface ObjectProvider<T>

Type Parameters:
T - the object type
All Superinterfaces:
Iterable<T>, ObjectFactory<T>
public interface ObjectProvider<T> extends ObjectFactory<T>, Iterable<T>
A variant of ObjectFactory designed specifically for injection points, allowing for programmatic optionality and lenient not-unique handling.

In a BeanFactory environment, every ObjectProvider obtained from the factory will be bound to its BeanFactory for a specific bean type, matching all provider calls against factory-registered bean definitions. Note that all such calls dynamically operate on the underlying factory state, freshly resolving the requested target object on every call.

As of 5.1, this interface extends Iterable and provides Stream support. It can be therefore be used in for loops, provides Iterable.forEach(java.util.function.Consumer<? super T>) iteration and allows for collection-style stream() access.

As of 6.2, this interface declares default implementations for all methods. This makes it easier to implement in a custom fashion, for example, for unit tests. For typical purposes, implement stream() to enable all other methods. Alternatively, you may implement the specific methods that your callers expect, for example, just getObject() or getIfAvailable().

Note that getObject() never returns null - it will throw a NoSuchBeanDefinitionException instead -, whereas getIfAvailable() will return null if no matching bean is present at all. However, both methods will throw a NoUniqueBeanDefinitionException if more than one matching bean is found without a clear unique winner (see below). Last but not least, getIfUnique() will return null both when no matching bean is found and when more than one matching bean is found without a unique winner.

Uniqueness is generally up to the container's candidate resolution algorithm but always honors the "primary" flag (with only one of the candidate beans marked as primary) and the "fallback" flag (with only one of the candidate beans not marked as fallback). The default-candidate flag is consistently taken into account as well, even for non-annotation-based injection points, with a single default candidate winning in case of no clear primary/fallback indication.

Since:
4.3
Author:
Juergen Hoeller
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final Predicate<Class<?>>
    UNFILTERED
    A predicate for unfiltered type matches, including non-default candidates but still excluding non-autowire candidates when used on injection points.

  • Method Summary

    Modifier and Type
    Method
    Description
    default @Nullable T
    getIfAvailable()
    Return an instance (possibly shared or independent) of the object managed by this factory.
    default T
    getIfAvailable(Supplier<T> defaultSupplier)
    Return an instance (possibly shared or independent) of the object managed by this factory.
    default @Nullable T
    getIfUnique()
    Return an instance (possibly shared or independent) of the object managed by this factory.
    default T
    getIfUnique(Supplier<T> defaultSupplier)
    Return an instance (possibly shared or independent) of the object managed by this factory.
    default T
    getObject()
    Return an instance (possibly shared or independent) of the object managed by this factory.
    default T
    getObject(@Nullable Object... args)
    Return an instance (possibly shared or independent) of the object managed by this factory.
    default void
    ifAvailable(Consumer<T> dependencyConsumer)
    Consume an instance (possibly shared or independent) of the object managed by this factory, if available.
    default void
    ifUnique(Consumer<T> dependencyConsumer)
    Consume an instance (possibly shared or independent) of the object managed by this factory, if unique.
    default Iterator<T>
    iterator()
    Return an Iterator over all matching object instances, without specific ordering guarantees (but typically in registration order).
    default Stream<T>
    orderedStream()
    Return a sequential Stream over all matching object instances, pre-ordered according to the factory's common order comparator.
    default Stream<T>
    orderedStream(Predicate<Class<?>> customFilter)
    Return a custom-filtered Stream over all matching object instances, pre-ordered according to the factory's common order comparator.
    default Stream<T>
    orderedStream(Predicate<Class<?>> customFilter, boolean includeNonSingletons)
    Return a custom-filtered Stream over all matching object instances, pre-ordered according to the factory's common order comparator.
    default Stream<T>
    stream()
    Return a sequential Stream over all matching object instances, without specific ordering guarantees (but typically in registration order).
    default Stream<T>
    stream(Predicate<Class<?>> customFilter)
    Return a custom-filtered Stream over all matching object instances, without specific ordering guarantees (but typically in registration order).
    default Stream<T>
    stream(Predicate<Class<?>> customFilter, boolean includeNonSingletons)
    Return a custom-filtered Stream over all matching object instances, without specific ordering guarantees (but typically in registration order).

    Methods inherited from interface java.lang.Iterable

    forEach, spliterator

  • Field Details

  • Method Details

    • getObject

      default T getObject() throws BeansException
      Description copied from interface: ObjectFactory
      Return an instance (possibly shared or independent) of the object managed by this factory.
      Specified by:
      getObject in interface ObjectFactory<T>
      Returns:
      the resulting instance
      Throws:
      BeansException - in case of creation errors

    • getObject

      default T getObject(@Nullable Object... args) throws BeansException
      Return an instance (possibly shared or independent) of the object managed by this factory.

      Allows for specifying explicit construction arguments, along the lines of BeanFactory.getBean(String, Object...).

      Parameters:
      args - arguments to use when creating a corresponding instance
      Returns:
      an instance of the bean
      Throws:
      BeansException - in case of creation errors
      See Also:

    • getIfAvailable

      default @Nullable T getIfAvailable() throws BeansException
      Return an instance (possibly shared or independent) of the object managed by this factory.
      Returns:
      an instance of the bean, or null if not available
      Throws:
      BeansException - in case of creation errors
      See Also:

    • getIfAvailable

      default T getIfAvailable(Supplier<T> defaultSupplier) throws BeansException
      Return an instance (possibly shared or independent) of the object managed by this factory.
      Parameters:
      defaultSupplier - a callback for supplying a default object if none is present in the factory
      Returns:
      an instance of the bean, or the supplied default object if no such bean is available
      Throws:
      BeansException - in case of creation errors
      Since:
      5.0
      See Also:

    • ifAvailable

      default void ifAvailable(Consumer<T> dependencyConsumer) throws BeansException
      Consume an instance (possibly shared or independent) of the object managed by this factory, if available.
      Parameters:
      dependencyConsumer - a callback for processing the target object if available (not called otherwise)
      Throws:
      BeansException - in case of creation errors
      Since:
      5.0
      See Also:

    • getIfUnique

      default @Nullable T getIfUnique() throws BeansException
      Return an instance (possibly shared or independent) of the object managed by this factory.
      Returns:
      an instance of the bean, or null if not available or not unique (i.e. multiple candidates found with none marked as primary)
      Throws:
      BeansException - in case of creation errors
      See Also:

    • getIfUnique

      default T getIfUnique(Supplier<T> defaultSupplier) throws BeansException
      Return an instance (possibly shared or independent) of the object managed by this factory.
      Parameters:
      defaultSupplier - a callback for supplying a default object if no unique candidate is present in the factory
      Returns:
      an instance of the bean, or the supplied default object if no such bean is available or if it is not unique in the factory (i.e. multiple candidates found with none marked as primary)
      Throws:
      BeansException - in case of creation errors
      Since:
      5.0
      See Also:

    • ifUnique

      default void ifUnique(Consumer<T> dependencyConsumer) throws BeansException
      Consume an instance (possibly shared or independent) of the object managed by this factory, if unique.
      Parameters:
      dependencyConsumer - a callback for processing the target object if unique (not called otherwise)
      Throws:
      BeansException - in case of creation errors
      Since:
      5.0
      See Also:

    • iterator

      default Iterator<T> iterator()
      Return an Iterator over all matching object instances, without specific ordering guarantees (but typically in registration order).
      Specified by:
      iterator in interface Iterable<T>
      Since:
      5.1
      See Also:

    • stream

      default Stream<T> stream()
      Return a sequential Stream over all matching object instances, without specific ordering guarantees (but typically in registration order).

      Note: The result may be filtered by default according to qualifiers on the injection point versus target beans and the general autowire candidate status of matching beans. For custom filtering against type-matching candidates, use stream(Predicate) instead (potentially with UNFILTERED).

      Since:
      5.1
      See Also:

    • orderedStream

      default Stream<T> orderedStream()
      Return a sequential Stream over all matching object instances, pre-ordered according to the factory's common order comparator.

      In a standard Spring application context, this will be ordered according to Ordered conventions, and in case of annotation-based configuration also considering the Order annotation, analogous to multi-element injection points of list/array type.

      The default method applies an OrderComparator to the stream() method. You may override this to apply an AnnotationAwareOrderComparator if necessary.

      Note: The result may be filtered by default according to qualifiers on the injection point versus target beans and the general autowire candidate status of matching beans. For custom filtering against type-matching candidates, use stream(Predicate) instead (potentially with UNFILTERED).

      Since:
      5.1
      See Also:

    • stream

      default Stream<T> stream(Predicate<Class<?>> customFilter)
      Return a custom-filtered Stream over all matching object instances, without specific ordering guarantees (but typically in registration order).
      Parameters:
      customFilter - a custom type filter for selecting beans among the raw bean type matches (or UNFILTERED for all raw type matches without any default filtering)
      Since:
      6.2.3
      See Also:

    • orderedStream

      default Stream<T> orderedStream(Predicate<Class<?>> customFilter)
      Return a custom-filtered Stream over all matching object instances, pre-ordered according to the factory's common order comparator.
      Parameters:
      customFilter - a custom type filter for selecting beans among the raw bean type matches (or UNFILTERED for all raw type matches without any default filtering)
      Since:
      6.2.3
      See Also:

    • stream

      default Stream<T> stream(Predicate<Class<?>> customFilter, boolean includeNonSingletons)
      Return a custom-filtered Stream over all matching object instances, without specific ordering guarantees (but typically in registration order).
      Parameters:
      customFilter - a custom type filter for selecting beans among the raw bean type matches (or UNFILTERED for all raw type matches without any default filtering)
      includeNonSingletons - whether to include prototype or scoped beans too or just singletons (also applies to FactoryBeans)
      Since:
      6.2.5
      See Also:

    • orderedStream

      default Stream<T> orderedStream(Predicate<Class<?>> customFilter, boolean includeNonSingletons)
      Return a custom-filtered Stream over all matching object instances, pre-ordered according to the factory's common order comparator.
      Parameters:
      customFilter - a custom type filter for selecting beans among the raw bean type matches (or UNFILTERED for all raw type matches without any default filtering)
      includeNonSingletons - whether to include prototype or scoped beans too or just singletons (also applies to FactoryBeans)
      Since:
      6.2.5
      See Also: