public interface

Binding

implements Element
com.google.inject.Binding<T>
Known Indirect Subclasses

Class Overview

A mapping from a key (type and optional annotation) to the strategy for getting instances of the type. This interface is part of the introspection API and is intended primarily for use by tools.

Bindings are created in several ways:

  • Explicitly in a module, via bind() and bindConstant() statements: 
         bind(Service.class).annotatedWith(Red.class).to(ServiceImpl.class);
     bindConstant().annotatedWith(ServerHost.class).to(args[0]);
  • Implicitly by the Injector by following a type's pointer annotations or by using its annotated or default constructor.
  • By converting a bound instance to a different type.
  • For providers, by delegating to the binding for the provided type.

They exist on both modules and on injectors, and their behaviour is different for each:

  • Module bindings are incomplete and cannot be used to provide instances. This is because the applicable scopes and interceptors may not be known until an injector is created. From a tool's perspective, module bindings are like the injector's source code. They can be inspected or rewritten, but this analysis must be done statically.
  • Injector bindings are complete and valid and can be used to provide instances. From a tools' perspective, injector bindings are like reflection for an injector. They have full runtime information, including the complete graph of injections necessary to satisfy a binding.

Summary

Public Methods
abstract <V> V acceptScopingVisitor(BindingScopingVisitor<V> visitor)
Accepts a scoping visitor.
abstract <V> V acceptTargetVisitor(BindingTargetVisitor<? super T, V> visitor)
Accepts a target visitor.
abstract Key<T> getKey()
Returns the key for this binding.
abstract Provider<T> getProvider()
Returns the scoped provider guice uses to fulfill requests for this binding.
[Expand]
Inherited Methods
From interface com.google.inject.spi.Element

Public Methods

public abstract V acceptScopingVisitor (BindingScopingVisitor<V> visitor)

Accepts a scoping visitor. Invokes the visitor method specific to this binding's scoping.

Parameters
visitor to call back on

public abstract V acceptTargetVisitor (BindingTargetVisitor<? super T, V> visitor)

Accepts a target visitor. Invokes the visitor method specific to this binding's target.

Parameters
visitor to call back on

public abstract Key<T> getKey ()

Returns the key for this binding.

public abstract Provider<T> getProvider ()

Returns the scoped provider guice uses to fulfill requests for this binding.

Throws
UnsupportedOperationException when invoked on a Binding created via getElements(Module...). This method is only supported on Bindings returned from an injector.