Package org.elasticsearch.common.inject.multibindings

Class Multibinder<T>

java.lang.Object

org.elasticsearch.common.inject.multibindings.Multibinder<T>

Direct Known Subclasses:

Multibinder.RealMultibinder

public abstract class Multibinder<T>
extends Object

An API to bind multiple values separately, only to later inject them as a complete collection. Multibinder is intended for use in your application's module:

 public class SnacksModule extends AbstractModule {
   protected void configure() {
     Multibinder<Snack> multibinder
         = Multibinder.newSetBinder(binder(), Snack.class);
     multibinder.addBinding().toInstance(new Twix());
     multibinder.addBinding().toProvider(SnickersProvider.class);
     multibinder.addBinding().to(Skittles.class);
   }
 }

With this binding, a Set<Snack> can now be injected:

 class SnackMachine {
   @Inject
   public SnackMachine(Set<Snack> snacks) { ... }
 }

Create multibindings from different modules is supported. For example, it is okay to have both CandyModule and ChipsModule to both create their own Multibinder<Snack>, and to each contribute bindings to the set of snacks. When that set is injected, it will contain elements from both modules.

Elements are resolved at set injection time. If an element is bound to a provider, that provider's get method will be called each time the set is injected (unless the binding is also scoped).

Annotations are be used to create different sets of the same element type. Each distinct annotation gets its own independent collection of elements.

Elements must be distinct. If multiple bound elements have the same value, set injection will fail.

Elements must be non-null. If any set element is null, set injection will fail.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Multibinder.RealMultibinder<T>	The actual multibinder plays several roles:

Method Summary

Modifier and Type	Method	Description
abstract LinkedBindingBuilder<T>	addBinding()	Returns a binding builder used to add a new element in the set.
static <T> Multibinder<T>	newSetBinder(Binder binder, Class<T> type)	Returns a new multibinder that collects instances of type in a Set that is itself bound with no binding annotation.
static <T> Multibinder<T>	newSetBinder(Binder binder, Class<T> type, Annotation annotation)	Returns a new multibinder that collects instances of type in a Set that is itself bound with annotation.
static <T> Multibinder<T>	newSetBinder(Binder binder, Class<T> type, Class<? extends Annotation> annotationType)	Returns a new multibinder that collects instances of type in a Set that is itself bound with annotationType.
static <T> Multibinder<T>	newSetBinder(Binder binder, TypeLiteral<T> type)	Returns a new multibinder that collects instances of type in a Set that is itself bound with no binding annotation.
static <T> Multibinder<T>	newSetBinder(Binder binder, TypeLiteral<T> type, Annotation annotation)	Returns a new multibinder that collects instances of type in a Set that is itself bound with annotation.
static <T> Multibinder<T>	newSetBinder(Binder binder, TypeLiteral<T> type, Class<? extends Annotation> annotationType)	Returns a new multibinder that collects instances of type in a Set that is itself bound with annotationType.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

newSetBinder

public static <T> Multibinder<T> newSetBinder(Binder binder,
 TypeLiteral<T> type)

Returns a new multibinder that collects instances of type in a Set that is itself bound with no binding annotation.

newSetBinder

public static <T> Multibinder<T> newSetBinder(Binder binder,
 Class<T> type)

Returns a new multibinder that collects instances of type in a Set that is itself bound with no binding annotation.

newSetBinder

public static <T> Multibinder<T> newSetBinder(Binder binder,
 TypeLiteral<T> type,
 Annotation annotation)

Returns a new multibinder that collects instances of type in a Set that is itself bound with annotation.

newSetBinder

public static <T> Multibinder<T> newSetBinder(Binder binder,
 Class<T> type,
 Annotation annotation)

Returns a new multibinder that collects instances of type in a Set that is itself bound with annotation.

newSetBinder

public static <T> Multibinder<T> newSetBinder(Binder binder,
 TypeLiteral<T> type,
 Class<? extends Annotation> annotationType)

Returns a new multibinder that collects instances of type in a Set that is itself bound with annotationType.

newSetBinder

public static <T> Multibinder<T> newSetBinder(Binder binder,
 Class<T> type,
 Class<? extends Annotation> annotationType)

Returns a new multibinder that collects instances of type in a Set that is itself bound with annotationType.

addBinding

public abstract LinkedBindingBuilder<T> addBinding()

Returns a binding builder used to add a new element in the set. Each bound element must have a distinct value. Bound providers will be evaluated each time the set is injected.

It is an error to call this method without also calling one of the to methods on the returned binding builder.

Scoping elements independently is supported. Use the in method to specify a binding scope.