org.grouplens.grapht.reflect.internal

Class NullSatisfaction

java.lang.Object

org.grouplens.grapht.reflect.internal.NullSatisfaction

All Implemented Interfaces:

Serializable, Satisfaction

public class NullSatisfaction
extends Object
implements Satisfaction, Serializable

NullSatisfaction is a satisfaction that explicitly satisfies desires with the null value.

Author:

GroupLens Research

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
NullSatisfaction(Class<?> type) Create a NullSatisfaction that uses null to satisfy the given class type.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object o)
CachePolicy	getDefaultCachePolicy() Get the default cache policy for instances created by this satisfaction.
List<Desire>	getDependencies() Get this satisfaction's dependencies.
Class<?>	getErasedType() Get the type-erased class of this satisfaction's type.
Type	getType() Get the type of this satisfaction.
int	hashCode()
boolean	hasInstance() Query whether this satisfaction already has an instance to return.
Instantiator	makeInstantiator(Map<Desire,Instantiator> dependencies) Create an instantiator from this satisfaction.
String	toString()
<T> T	visit(SatisfactionVisitor<T> visitor) Visit the satisfaction.

Methods inherited from class java.lang.Object

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

Constructor Detail

NullSatisfaction

public NullSatisfaction(Class<?> type)

Create a NullSatisfaction that uses null to satisfy the given class type.

Parameters:

type - The type to satisfy

Throws:

NullPointerException - if type is null

Method Detail

getDefaultCachePolicy

public CachePolicy getDefaultCachePolicy()

Description copied from interface: Satisfaction

Get the default cache policy for instances created by this satisfaction. In most cases this should be NO_PREFERENCE, but annotations such as Singleton can be used to specify a default. BindingFunctions are allowed to overrule the default cache policy.

Specified by:

getDefaultCachePolicy in interface Satisfaction

Returns:

The default cache policy if no function overrules it

getDependencies

public List<Desire> getDependencies()

Description copied from interface: Satisfaction

Get this satisfaction's dependencies.

Specified by:

getDependencies in interface Satisfaction

Returns:

A list of dependencies which must be satisfied in order to instantiate this satisfaction.

getType

public Type getType()

Description copied from interface: Satisfaction

Get the type of this satisfaction. If this is a synthetic Satisfaction, then a null type is returned.

Specified by:

getType in interface Satisfaction

Returns:

The type of objects to be instantiated by this satisfaction.

getErasedType

public Class<?> getErasedType()

Description copied from interface: Satisfaction

Get the type-erased class of this satisfaction's type. If this is a synthetic Satisfaction, then null is returned.

Specified by:

getErasedType in interface Satisfaction

Returns:

The class object for this satisfaction's type.

hasInstance

public boolean hasInstance()

Description copied from interface: Satisfaction

Query whether this satisfaction already has an instance to return. If true, then this satisfaction's provider will just return an instance that is already in existence; if false, then its provider may create new instances.

Specified by:

hasInstance in interface Satisfaction

Returns:

whether the satisfaction already has an instance.

visit

public <T> T visit(SatisfactionVisitor<T> visitor)

Description copied from interface: Satisfaction

Visit the satisfaction. This method invokes the appropriate method on the provided visitor to report information on itself.

Specified by:

visit in interface Satisfaction

Type Parameters:

T - The type returned from the visitor.

Parameters:

visitor - The visitor object.

Returns:

The return value from the invoked visitor method.

makeInstantiator

public Instantiator makeInstantiator(Map<Desire,Instantiator> dependencies)

Description copied from interface: Satisfaction

Create an instantiator from this satisfaction.

If the details of the Satisfaction require instantiation (e.g. a class or provider class satisfaction), the returned provider should be a new instance, and it should perform no memoization of its own. Caching is the purview of Injector implementations.

If the satisfaction is configured to use specific instances, this rule is obviously void.

Specified by:

makeInstantiator in interface Satisfaction

Parameters:

dependencies - A function mapping desires to providers of their instances.

Returns:

An instantiator of new instances of the type specified by this satisfaction, instantiated using the specified dependency mapping.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object