com.google.inject.assistedinject

Class FactoryProvider<F>

java.lang.Object

com.google.inject.assistedinject.FactoryProvider<F>

Type Parameters:

F - The factory interface

All Implemented Interfaces:

HasDependencies, javax.inject.Provider<F>

Deprecated.

use FactoryModuleBuilder instead.

@Deprecated
public class FactoryProvider<F>
extends Object
implements Provider<F>, HasDependencies

Obsolete. Prefer FactoryModuleBuilder for its more concise API and additional capability.

Provides a factory that combines the caller's arguments with injector-supplied values to construct objects.

Defining a factory

Create an interface whose methods return the constructed type, or any of its supertypes. The method's parameters are the arguments required to build the constructed type.

public interface PaymentFactory {
   Payment create(Date startDate, Money amount);
 }

You can name your factory methods whatever you like, such as create, createPayment or newPayment.

Creating a type that accepts factory parameters

constructedType is a concrete class with an @Inject-annotated constructor. In addition to injector-supplied parameters, the constructor should have parameters that match each of the factory method's parameters. Each factory-supplied parameter requires an @Assisted annotation. This serves to document that the parameter is not bound by your application's modules.

public class RealPayment implements Payment {
   @Inject
   public RealPayment(
      CreditService creditService,
      AuthService authService,
      @Assisted Date startDate,
      @Assisted Money amount) {
     ...
   }
 }

Any parameter that permits a null value should also be annotated @Nullable.

Configuring factories

In your module, bind the factory interface to the returned factory:

bind(PaymentFactory.class).toProvider(
     FactoryProvider.newFactory(PaymentFactory.class, RealPayment.class));

As a side-effect of this binding, Guice will inject the factory to initialize it for use. The factory cannot be used until the injector has been initialized.

Using the factory

Inject your factory into your application classes. When you use the factory, your arguments will be combined with values from the injector to construct an instance.

public class PaymentAction {
   @Inject private PaymentFactory paymentFactory;

   public void doPayment(Money amount) {
     Payment payment = paymentFactory.create(new Date(), amount);
     payment.apply();
   }
 }

Making parameter types distinct

The types of the factory method's parameters must be distinct. To use multiple parameters of the same type, use a named @Assisted annotation to disambiguate the parameters. The names must be applied to the factory method's parameters:

public interface PaymentFactory {
   Payment create(
       @Assisted("startDate") Date startDate,
       @Assisted("dueDate") Date dueDate,
       Money amount);
 } 

...and to the concrete type's constructor parameters:

public class RealPayment implements Payment {
   @Inject
   public RealPayment(
      CreditService creditService,
      AuthService authService,
      @Assisted("startDate") Date startDate,
      @Assisted("dueDate") Date dueDate,
      @Assisted Money amount) {
     ...
   }
 }

Values are created by Guice

Returned factories use child injectors to create values. The values are eligible for method interception. In addition, @Inject members will be injected before they are returned.

Backwards compatibility using @AssistedInject

Instead of the @Inject annotation, you may annotate the constructed classes with @AssistedInject. This triggers a limited backwards-compatability mode.

Instead of matching factory method arguments to constructor parameters using their names, the parameters are matched by their order. The first factory method argument is used for the first @Assisted constructor parameter, etc.. Annotation names have no effect.

Returned values are not created by Guice. These types are not eligible for method interception. They do receive post-construction member injection.

Author:

jmourits@google.com (Jerome Mourits), jessewilson@google.com (Jesse Wilson), dtm@google.com (Daniel Martin)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object obj) Deprecated.
F	get() Deprecated.
Set<Dependency<?>>	getDependencies() Deprecated.
int	hashCode() Deprecated.
static <F> Provider<F>	newFactory(Class<F> factoryType, Class<?> implementationType) Deprecated.
static <F> Provider<F>	newFactory(TypeLiteral<F> factoryType, TypeLiteral<?> implementationType) Deprecated.

Methods inherited from class java.lang.Object

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

Method Detail

newFactory

public static <F> Provider<F> newFactory(Class<F> factoryType,
                         Class<?> implementationType)

Deprecated.

newFactory

public static <F> Provider<F> newFactory(TypeLiteral<F> factoryType,
                         TypeLiteral<?> implementationType)

Deprecated.

getDependencies

public Set<Dependency<?>> getDependencies()

Deprecated.

Specified by:

getDependencies in interface HasDependencies

get

public F get()

Deprecated.

Specified by:

get in interface javax.inject.Provider<F>

hashCode

public int hashCode()

Deprecated.

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Deprecated.

Overrides:

equals in class Object