com.helger.commons.scopes.singleton

Class ApplicationSingleton

java.lang.Object

com.helger.commons.scopes.AbstractSingleton

com.helger.commons.scopes.singleton.ApplicationSingleton

All Implemented Interfaces:

IScopeDestructionAware

Direct Known Subclasses:

ApplicationSingletonTreeWithUniqueID

public abstract class ApplicationSingleton
extends AbstractSingleton

This is the base class for singleton objects that reside in the application scope. This is the same for web scopes and non-web scopes, as application scopes are managed in the global scope which is also identical for web scopes and non-web scopes.

Author:

Philip Helger

See Also:

EScope.APPLICATION

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ApplicationSingleton()

Method Summary

Methods

Modifier and Type	Method and Description
static List<ApplicationSingleton>	getAllApplicationSingletons() Get all instantiated singleton objects registered in the current application scope.
static <T extends ApplicationSingleton> T	getApplicationSingleton(Class<T> aClass) Get the singleton object in the current application scope, using the passed class.
static <T extends ApplicationSingleton> T	getApplicationSingletonIfInstantiated(Class<T> aClass) Get the singleton object if it is already instantiated inside the current application scope or null if it is not instantiated.
static boolean	isApplicationSingletonInstantiated(Class<? extends ApplicationSingleton> aClass) Check if a singleton is already instantiated inside the current application scope

Methods inherited from class com.helger.commons.scopes.AbstractSingleton

getAllSingletons, getSingleton, getSingletonIfInstantiated, getSingletonScopeKey, isDestroyed, isInDestruction, isInInstantiation, isInstantiated, isSingletonInstantiated, isUsableObject, onAfterInstantiation, onDestroy, onScopeDestruction, readAbstractSingletonFields, setDestroyed, setInDestruction, setInInstantiation, setInstantiated, toString, writeAbstractSingletonFields

Methods inherited from class java.lang.Object

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

Constructor Detail

ApplicationSingleton

protected ApplicationSingleton()

Method Detail

getApplicationSingleton

@Nonnull
public static final <T extends ApplicationSingleton> T getApplicationSingleton(@Nonnull
                                                                 Class<T> aClass)

Get the singleton object in the current application scope, using the passed class. If the singleton is not yet instantiated, a new instance is created.

Parameters:

aClass - The class to be used. May not be null. The class must be public as needs to have a public no-argument constructor.

Returns:

The singleton object and never null.

getApplicationSingletonIfInstantiated

@Nullable
public static final <T extends ApplicationSingleton> T getApplicationSingletonIfInstantiated(@Nonnull
                                                                                Class<T> aClass)

Get the singleton object if it is already instantiated inside the current application scope or null if it is not instantiated.

Parameters:

aClass - The class to be checked. May not be null.

Returns:

The singleton for the specified class is already instantiated, null otherwise.

isApplicationSingletonInstantiated

public static final boolean isApplicationSingletonInstantiated(@Nonnull
                                         Class<? extends ApplicationSingleton> aClass)

Check if a singleton is already instantiated inside the current application scope

Parameters:

aClass - The class to be checked. May not be null.

Returns:

true if the singleton for the specified class is already instantiated, false otherwise.

getAllApplicationSingletons

@Nonnull
public static final List<ApplicationSingleton> getAllApplicationSingletons()

Get all instantiated singleton objects registered in the current application scope.

Returns:

A non-null list with all instances of this class in the current application scope.