org.apache.reef.tang

Interface Injector

All Known Implementing Classes:

InjectorImpl

public interface Injector

Method Summary

Methods

Modifier and Type	Method and Description
<T> void	bindAspect(Aspect a) Binds a TANG Aspect to this injector.
<T> void	bindVolatileInstance(Class<T> iface, T inst) Binds the given object to the class.
<T> void	bindVolatileParameter(Class<? extends Name<T>> iface, T inst)
Injector	forkInjector()
Injector	forkInjector(Configuration... configurations) Create a copy of this Injector that inherits the instances that were already created by this Injector, but reflects additional Configuration objects.
Aspect	getAspect() Allows InjectionFuture to tell the aspect when get() is invoked.
<T> InjectionPlan<T>	getInjectionPlan(Class<T> name)
InjectionPlan<?>	getInjectionPlan(String name)
<U> U	getInstance(Class<U> iface) Gets an instance of iface, or the implementation that has been bound to it.
<U> U	getInstance(String iface) Gets an instance of iface, or the implementation that has been bound to it.
<U> U	getNamedInstance(Class<? extends Name<U>> iface) Gets the value stored for the given named parameter.
boolean	isInjectable(Class<?> clazz)
boolean	isInjectable(String name) Returns true if this Injector is able to instantiate the object named by name.
boolean	isParameterSet(Class<? extends Name<?>> name)
boolean	isParameterSet(String name)

Method Detail

getInstance

<U> U getInstance(Class<U> iface)
              throws InjectionException

Gets an instance of iface, or the implementation that has been bound to it. If an instance has already been created in this (or a parent) scope, then the existing instance will be returned. Otherwise, a new instance will be returned, and registered in the current scope.

Type Parameters:

U - a type

Parameters:

iface - an interface

Returns:

an instance

Throws:

InjectionException - if it fails to find corresponding class

getInstance

<U> U getInstance(String iface)
              throws InjectionException,
                     NameResolutionException

Gets an instance of iface, or the implementation that has been bound to it. If an instance has already been created in this (or a parent) scope, then the existing instance will be returned. Otherwise, a new instance will be returned, and registered in the current scope.

Type Parameters:

U - a type

Parameters:

iface - a name of interface

Returns:

an instance

Throws:

InjectionException - if it fails to find corresponding class

NameResolutionException - if name resolution fails

getNamedInstance

<U> U getNamedInstance(Class<? extends Name<U>> iface)
                   throws InjectionException

Gets the value stored for the given named parameter.

Type Parameters:

U - a type

Parameters:

iface - the name of interface

Returns:

an Instance of the class configured as the implementation for the given interface class.

Throws:

InjectionException - if name resolution fails

bindVolatileInstance

<T> void bindVolatileInstance(Class<T> iface,
                            T inst)
                          throws BindException

Binds the given object to the class. Note that this only affects objects created by the returned Injector and its children. Also, like all Injectors, none of those objects can be serialized back to a configuration file).

Type Parameters:

T - a type

Parameters:

iface - an interface cass

inst - an instance

Throws:

BindException - when trying to re-bind

bindVolatileParameter

<T> void bindVolatileParameter(Class<? extends Name<T>> iface,
                             T inst)
                           throws BindException

Throws:

BindException

bindAspect

<T> void bindAspect(Aspect a)
                throws BindException

Binds a TANG Aspect to this injector. Tang Aspects interpose on each injection performed by an injector, and return an instance of their choosing.

A given aspect will be invoked once for each object that Tang injects, and aspects will be copied in a way that mirrors the scoping that Tang creates at runtime.

Type Parameters:

T - a type

Parameters:

a - aspect

Throws:

BindException - if there exists a bound aspect already

getAspect

Aspect getAspect()

Allows InjectionFuture to tell the aspect when get() is invoked. Package private.

Returns:

the aspect

forkInjector

Injector forkInjector(Configuration... configurations)
                      throws BindException

Create a copy of this Injector that inherits the instances that were already created by this Injector, but reflects additional Configuration objects. This can be used to create trees of Injectors that obey hierarchical scoping rules.

Except for the fact that the child Injector will have references to this injector's instances, the returned Injector is equivalent to the one you would get by using ConfigurationBuilder to build a merged Configuration, and then using the merged Configuration to create an Injector. Injectors returned by ConfigurationBuilders are always independent, and never share references to the same instances of injected objects.

Parameters:

configurations - configurations

Returns:

an injector

Throws:

BindException - If any of the configurations conflict with each other, or the existing Injector's Configuration.

isInjectable

boolean isInjectable(String name)
                     throws BindException

Returns true if this Injector is able to instantiate the object named by name.

Parameters:

name - a name of object

Returns:

whether the name is injectable

Throws:

BindException - if there is a loop or the name is package name

isParameterSet

boolean isParameterSet(String name)
                       throws BindException

Throws:

BindException

isInjectable

boolean isInjectable(Class<?> clazz)
                     throws BindException

Throws:

BindException

isParameterSet

boolean isParameterSet(Class<? extends Name<?>> name)
                       throws BindException

Throws:

BindException

getInjectionPlan

InjectionPlan<?> getInjectionPlan(String name)
                                  throws NameResolutionException

Throws:

NameResolutionException

getInjectionPlan

<T> InjectionPlan<T> getInjectionPlan(Class<T> name)

forkInjector

Injector forkInjector()