ch.jalu.injector

Class InjectorImpl

java.lang.Object

ch.jalu.injector.InjectorImpl

All Implemented Interfaces:

Injector

public class InjectorImpl
extends Object
implements Injector

Implementation of Injector.

Field Summary

Fields

Modifier and Type	Field and Description
protected InjectorConfig	config
protected Map<Class<?>,Object>	objects

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	InjectorImpl(InjectorConfig config) Constructor.

Method Summary

Modifier and Type	Method and Description
<T> T	createIfHasDependencies(Class<T> clazz) Creates an instance of the given class if all of its dependencies are available.
protected Resolution<?>	findResolutionOrFail(ResolutionContext context) Calls the defined handlers and returns the first Resolution that is returned based on the provided resolution context.
InjectorConfig	getConfig()
<T> T	getIfAvailable(Class<T> clazz) Returns the singleton of the given class if available.
<T> T	getSingleton(Class<T> clazz) Retrieves or instantiates an object of the given type (singleton scope).
<T> T	newInstance(Class<T> clazz) Request-scoped method to instantiate a new object of the given class.
void	provide(Class<? extends Annotation> clazz, Object object) Processes an annotation with an associated object.
<T> void	register(Class<? super T> clazz, T object) Registers an object as the singleton of the given class.
<T,P extends javax.inject.Provider<? extends T>> void	registerProvider(Class<T> clazz, Class<P> providerClass) Registers the provider class to instantiate a given class.
<T> void	registerProvider(Class<T> clazz, javax.inject.Provider<? extends T> provider) Registers a provider for the given class.
protected Object	resolveContext(ResolutionContext context) Returns the object as defined by the given context.
protected Object[]	resolveDependencies(ResolutionContext context, Resolution<?> resolution) Resolves the dependencies as defined by the given resolution.
<T> Collection<T>	retrieveAllOfType(Class<T> clazz) Returns all known singletons of the given type.
protected <T> T	runPostConstructHandlers(T instance, ResolutionContext context, Resolution<?> resolution) Invokes the handler's post construct method when appropriate.
protected void	throwForUnexpectedNullDependency(ResolutionContext context) Called when a resolved dependency is null, this method may throw an exception in the cases when this should not happen.

Methods inherited from class java.lang.Object

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

Field Detail

objects

protected Map<Class<?>,Object> objects

config

protected InjectorConfig config

Constructor Detail

InjectorImpl

protected InjectorImpl(InjectorConfig config)

Constructor.

Parameters:

config - injector configuration

See Also:

InjectorBuilder

Method Detail

register

public <T> void register(Class<? super T> clazz,
                         T object)

Description copied from interface: Injector

Registers an object as the singleton of the given class. Throws an exception if a singleton is already available for the class.

Specified by:

register in interface Injector

Type Parameters:

T - the type to register the object for

Parameters:

clazz - the class to register the object for

object - the object

provide

public void provide(Class<? extends Annotation> clazz,
                    Object object)

Description copied from interface: Injector

Processes an annotation with an associated object. The actual behavior of this method depends on the configured handlers of the injector. By default it register the given object for the annotation such that it may be later injected with the annotation as identifier.

Specified by:

provide in interface Injector

Parameters:

clazz - the annotation

object - the object

getSingleton

public <T> T getSingleton(Class<T> clazz)

Description copied from interface: Injector

Retrieves or instantiates an object of the given type (singleton scope).

Specified by:

getSingleton in interface Injector

Type Parameters:

T - the class' type

Parameters:

clazz - the class to retrieve the value for

Returns:

object of the class' type

newInstance

public <T> T newInstance(Class<T> clazz)

Description copied from interface: Injector

Request-scoped method to instantiate a new object of the given class. The injector does not keep track of it afterwards; it will always return a new instance and forget about it.

Specified by:

newInstance in interface Injector

Type Parameters:

T - the class' type

Parameters:

clazz - the class to instantiate

Returns:

new instance of class T

getIfAvailable

public <T> T getIfAvailable(Class<T> clazz)

Description copied from interface: Injector

Returns the singleton of the given class if available. This simply returns the instance if present, and otherwise null. Calling this method will never create any new objects.

Specified by:

getIfAvailable in interface Injector

Type Parameters:

T - the class' type

Parameters:

clazz - the class to retrieve the instance for

Returns:

instance or null if not available

createIfHasDependencies

public <T> T createIfHasDependencies(Class<T> clazz)

Description copied from interface: Injector

Creates an instance of the given class if all of its dependencies are available. A new instance is returned each time and the created object is not stored in the injector.

Note: Currently, all dependencies of the class need to be registered singletons for a new instance to be created. This limitation may be lifted in future versions.

Specified by:

createIfHasDependencies in interface Injector

Type Parameters:

T - the class' type

Parameters:

clazz - the class to construct if possible

Returns:

instance of the class, or null if any dependency does not already exist

retrieveAllOfType

public <T> Collection<T> retrieveAllOfType(Class<T> clazz)

Description copied from interface: Injector

Returns all known singletons of the given type. Typically used with interfaces in order to perform an action without knowing its concrete implementors. Trivially, using Object as clazz will return all known singletons.

Specified by:

retrieveAllOfType in interface Injector

Type Parameters:

T - the class' type

Parameters:

clazz - the class to retrieve singletons of

Returns:

list of singletons of the given type

registerProvider

public <T> void registerProvider(Class<T> clazz,
                                 javax.inject.Provider<? extends T> provider)

Description copied from interface: Injector

Registers a provider for the given class. The provider is used whenever the class needs to be instantiated.

Specified by:

registerProvider in interface Injector

Type Parameters:

T - the class' type

Parameters:

clazz - the class to register the provider for

provider - the provider

registerProvider

public <T,P extends javax.inject.Provider<? extends T>> void registerProvider(Class<T> clazz,
                                                                              Class<P> providerClass)

Description copied from interface: Injector

Registers the provider class to instantiate a given class. The first time the clazz has to be instantiated, the providerClass will be instantiated.

Specified by:

registerProvider in interface Injector

Type Parameters:

T - the class' type

P - the provider's type

Parameters:

clazz - the class to register the provider for

providerClass - the class of the provider

getConfig

public InjectorConfig getConfig()

resolveContext

@Nullable
protected Object resolveContext(ResolutionContext context)

Returns the object as defined by the given context.

Parameters:

context - the context to resolve the object for

Returns:

the resolved object, null if the context specifies it is optional and some criteria is not met

resolveDependencies

protected Object[] resolveDependencies(ResolutionContext context,
                                       Resolution<?> resolution)

Resolves the dependencies as defined by the given resolution. If a dependency is resolved to null, the process is aborted and the remaining dependencies are not resolved.

Parameters:

context - the resolution context

resolution - the resolution whose dependencies should be provided

Returns:

array with the dependencies, in the same order as given by the resolution

throwForUnexpectedNullDependency

protected void throwForUnexpectedNullDependency(ResolutionContext context)

Called when a resolved dependency is null, this method may throw an exception in the cases when this should not happen. If this method does not throw an exception, null is returned from resolveContext(ch.jalu.injector.context.ResolutionContext).

Parameters:

context - the resolution context

findResolutionOrFail

protected Resolution<?> findResolutionOrFail(ResolutionContext context)

Calls the defined handlers and returns the first Resolution that is returned based on the provided resolution context. Throws an exception if no handler returned a resolution.

Parameters:

context - the context to find the resolution for

Returns:

the resolution

runPostConstructHandlers

protected <T> T runPostConstructHandlers(T instance,
                                         ResolutionContext context,
                                         Resolution<?> resolution)

Invokes the handler's post construct method when appropriate. Returns the object as returned by the handlers, which may be different from the provided one.

Type Parameters:

T - the object's type

Parameters:

instance - the object that was resolved

context - the resolution context

resolution - the resolution used to get the object

Returns:

the object to use (as post construct methods may change it)