com.google.inject.spi

Class ProviderLookup<T>

java.lang.Object

com.google.inject.spi.ProviderLookup<T>

All Implemented Interfaces:

Element

public final class ProviderLookup<T>
extends java.lang.Object
implements Element

A lookup of the provider for a type. Lookups are created explicitly in a module using getProvider() statements:

     Provider<PaymentService> paymentServiceProvider
         = getProvider(PaymentService.class);

Since:

2.0

Constructor Summary

Constructors

Constructor and Description
ProviderLookup(java.lang.Object source, Dependency<T> dependency)
ProviderLookup(java.lang.Object source, Key<T> key)

Method Summary

Modifier and Type	Method and Description
<T> T	acceptVisitor(ElementVisitor<T> visitor) Accepts an element visitor.
void	applyTo(Binder binder) Writes this module element to the given binder (optional operation).
Provider<T>	getDelegate() Returns the delegate provider, or null if it has not yet been initialized.
Dependency<T>	getDependency()
Key<T>	getKey()
Provider<T>	getProvider() Returns the looked up provider.
java.lang.Object	getSource() Returns an arbitrary object containing information about the "place" where this element was configured.
void	initializeDelegate(Provider<T> delegate) Sets the actual provider.

Methods inherited from class java.lang.Object

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

Constructor Detail

ProviderLookup

public ProviderLookup(java.lang.Object source,
                      Key<T> key)

ProviderLookup

public ProviderLookup(java.lang.Object source,
                      Dependency<T> dependency)

Since:

4.0

Method Detail

getSource

public java.lang.Object getSource()

Description copied from interface: Element

Returns an arbitrary object containing information about the "place" where this element was configured. Used by Guice in the production of descriptive error messages.

Tools might specially handle types they know about; StackTraceElement is a good example. Tools should simply call toString() on the source object if the type is unfamiliar.

Specified by:

getSource in interface Element

getKey

public Key<T> getKey()

getDependency

public Dependency<T> getDependency()

Since:

4.0

acceptVisitor

public <T> T acceptVisitor(ElementVisitor<T> visitor)

Description copied from interface: Element

Accepts an element visitor. Invokes the visitor method specific to this element's type.

Specified by:

acceptVisitor in interface Element

Parameters:

visitor - to call back on

initializeDelegate

public void initializeDelegate(Provider<T> delegate)

Sets the actual provider.

Throws:

java.lang.IllegalStateException - if the delegate is already set

applyTo

public void applyTo(Binder binder)

Description copied from interface: Element

Writes this module element to the given binder (optional operation).

Specified by:

applyTo in interface Element

Parameters:

binder - to apply configuration element to

getDelegate

public Provider<T> getDelegate()

Returns the delegate provider, or null if it has not yet been initialized. The delegate will be initialized when this element is processed, or otherwise used to create an injector.

getProvider

public Provider<T> getProvider()

Returns the looked up provider. The result is not valid until this lookup has been initialized, which usually happens when the injector is created. The provider will throw an IllegalStateException if you try to use it beforehand.