Package org.dellroad.stuff.spring

Class Springleton

java.lang.Object

org.springframework.context.support.ApplicationObjectSupport

org.dellroad.stuff.spring.Springleton

All Implemented Interfaces:

Aware, ApplicationContextAware

public class Springleton
extends ApplicationObjectSupport

Global singleton that provides access to the application context in which it is defined from anywhere. Reminiscent of Spring's "evil singleton" from days of yore.

This bean allows at most one instantiated instance per class loader, and that instance may be defined in at most one ApplicationContext. In particular, this means web containers hosting multiple web applications must create separate class loaders per web application.

This class may be subclassed to add autowired properties, etc. If so, access the singleton in the same way (i.e., via Springleton.getInstance()) and then downcast as needed.

Field Summary

Fields inherited from class org.springframework.context.support.ApplicationObjectSupport

logger

Constructor Summary

Constructors

Constructor	Description
Springleton()	Constructor.

Method Summary

Modifier and Type	Method	Description
static Springleton	getInstance()	Get the singleton instance.
boolean	isContextRequired()

Methods inherited from class org.springframework.context.support.ApplicationObjectSupport

getApplicationContext, getMessageSourceAccessor, initApplicationContext, initApplicationContext, obtainApplicationContext, requiredContextClass, setApplicationContext

Methods inherited from class java.lang.Object

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

Constructor Details

Springleton

public Springleton()

Constructor.

Throws:

IllegalStateException - if another instance has already been created in the same class loader

Method Details

getInstance

public static Springleton getInstance()

Get the singleton instance.

Returns:

Springleton singleton

Throws:

IllegalStateException - if no instance has been created yet

isContextRequired

public boolean isContextRequired()

The implementation in Springleton always returns true.

Overrides:

isContextRequired in class ApplicationObjectSupport