org.springframework.beans.factory.config

Interface SingletonBeanRegistry

All Known Subinterfaces:

ConfigurableBeanFactory, ConfigurableListableBeanFactory

All Known Implementing Classes:

AbstractAutowireCapableBeanFactory, AbstractBeanFactory, DefaultListableBeanFactory, DefaultSingletonBeanRegistry, FactoryBeanRegistrySupport, XmlBeanFactory

public interface SingletonBeanRegistry

Interface that defines a registry for shared bean instances. Can be implemented by BeanFactory implementations in order to expose their singleton management facility in a uniform manner.

The ConfigurableBeanFactory interface extends this interface.

Since:

2.0

Author:

Juergen Hoeller

See Also:

ConfigurableBeanFactory, DefaultSingletonBeanRegistry, AbstractBeanFactory

Method Summary

Modifier and Type	Method and Description
boolean	containsSingleton(String beanName) Check if this registry contains a singleton instance with the given name.
Object	getSingleton(String beanName) Return the (raw) singleton object registered under the given name.
int	getSingletonCount() Return the number of singleton beans registered in this registry.
Object	getSingletonMutex() Return the singleton mutex used by this registry (for external collaborators).
String[]	getSingletonNames() Return the names of singleton beans registered in this registry.
void	registerSingleton(String beanName, Object singletonObject) Register the given existing object as singleton in the bean registry, under the given bean name.

Method Detail

registerSingleton

void registerSingleton(String beanName,
                       Object singletonObject)

Register the given existing object as singleton in the bean registry, under the given bean name.

The given instance is supposed to be fully initialized; the registry will not perform any initialization callbacks (in particular, it won't call InitializingBean's afterPropertiesSet method). The given instance will not receive any destruction callbacks (like DisposableBean's destroy method) either.

When running within a full BeanFactory: Register a bean definition instead of an existing instance if your bean is supposed to receive initialization and/or destruction callbacks.

Typically invoked during registry configuration, but can also be used for runtime registration of singletons. As a consequence, a registry implementation should synchronize singleton access; it will have to do this anyway if it supports a BeanFactory's lazy initialization of singletons.

Parameters:

beanName - the name of the bean

singletonObject - the existing singleton object

See Also:

InitializingBean.afterPropertiesSet(), DisposableBean.destroy(), BeanDefinitionRegistry.registerBeanDefinition(java.lang.String, org.springframework.beans.factory.config.BeanDefinition)

getSingleton

@Nullable
Object getSingleton(String beanName)

Return the (raw) singleton object registered under the given name.

Only checks already instantiated singletons; does not return an Object for singleton bean definitions which have not been instantiated yet.

The main purpose of this method is to access manually registered singletons (see registerSingleton(java.lang.String, java.lang.Object)). Can also be used to access a singleton defined by a bean definition that already been created, in a raw fashion.

NOTE: This lookup method is not aware of FactoryBean prefixes or aliases. You need to resolve the canonical bean name first before obtaining the singleton instance.

Parameters:

beanName - the name of the bean to look for

Returns:

the registered singleton object, or null if none found

See Also:

ConfigurableListableBeanFactory.getBeanDefinition(java.lang.String)

containsSingleton

boolean containsSingleton(String beanName)

Check if this registry contains a singleton instance with the given name.

Only checks already instantiated singletons; does not return true for singleton bean definitions which have not been instantiated yet.

The main purpose of this method is to check manually registered singletons (see registerSingleton(java.lang.String, java.lang.Object)). Can also be used to check whether a singleton defined by a bean definition has already been created.

To check whether a bean factory contains a bean definition with a given name, use ListableBeanFactory's containsBeanDefinition. Calling both containsBeanDefinition and containsSingleton answers whether a specific bean factory contains a local bean instance with the given name.

Use BeanFactory's containsBean for general checks whether the factory knows about a bean with a given name (whether manually registered singleton instance or created by bean definition), also checking ancestor factories.

NOTE: This lookup method is not aware of FactoryBean prefixes or aliases. You need to resolve the canonical bean name first before checking the singleton status.

Parameters:

beanName - the name of the bean to look for

Returns:

if this bean factory contains a singleton instance with the given name

See Also:

registerSingleton(java.lang.String, java.lang.Object), ListableBeanFactory.containsBeanDefinition(java.lang.String), BeanFactory.containsBean(java.lang.String)

getSingletonNames

String[] getSingletonNames()

Return the names of singleton beans registered in this registry.

Only checks already instantiated singletons; does not return names for singleton bean definitions which have not been instantiated yet.

The main purpose of this method is to check manually registered singletons (see registerSingleton(java.lang.String, java.lang.Object)). Can also be used to check which singletons defined by a bean definition have already been created.

Returns:

the list of names as a String array (never null)

See Also:

registerSingleton(java.lang.String, java.lang.Object), BeanDefinitionRegistry.getBeanDefinitionNames(), ListableBeanFactory.getBeanDefinitionNames()

getSingletonCount

int getSingletonCount()

Return the number of singleton beans registered in this registry.

Only checks already instantiated singletons; does not count singleton bean definitions which have not been instantiated yet.

The main purpose of this method is to check manually registered singletons (see registerSingleton(java.lang.String, java.lang.Object)). Can also be used to count the number of singletons defined by a bean definition that have already been created.

Returns:

the number of singleton beans

See Also:

registerSingleton(java.lang.String, java.lang.Object), BeanDefinitionRegistry.getBeanDefinitionCount(), ListableBeanFactory.getBeanDefinitionCount()

getSingletonMutex

Object getSingletonMutex()

Return the singleton mutex used by this registry (for external collaborators).

Returns:

the mutex object (never null)

Since:

4.2