Package org.springframework.context

Interface ApplicationListener<E extends ApplicationEvent>

Type Parameters:

E - the specific ApplicationEvent subclass to listen to

All Superinterfaces:

EventListener

All Known Subinterfaces:

GenericApplicationListener, SmartApplicationListener, TransactionalApplicationListener<E>

All Known Implementing Classes:

ApplicationListenerMethodAdapter, DefaultSimpUserRegistry, ExecutorConfigurationSupport, GenericApplicationListenerAdapter, JmsListenerEndpointRegistry, MultiServerUserRegistry, ResourceUrlProvider, ResourceUrlProvider, ScheduledAnnotationBeanPostProcessor, ScheduledExecutorFactoryBean, SimpleAsyncTaskScheduler, SourceFilteringListener, ThreadPoolExecutorFactoryBean, ThreadPoolTaskExecutor, ThreadPoolTaskScheduler, TransactionalApplicationListenerAdapter, TransactionalApplicationListenerMethodAdapter, UserRegistryMessageHandler

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface ApplicationListener<E extends ApplicationEvent>
extends EventListener

Interface to be implemented by application event listeners.

Based on the standard EventListener interface for the Observer design pattern.

An ApplicationListener can generically declare the event type that it is interested in. When registered with a Spring ApplicationContext, events will be filtered accordingly, with the listener getting invoked for matching event objects only.

Author:

Rod Johnson, Juergen Hoeller

See Also:

• ApplicationEvent
• ApplicationEventMulticaster
• SmartApplicationListener
• GenericApplicationListener
• EventListener

Method Summary

Modifier and Type	Method	Description
static <T> ApplicationListener<PayloadApplicationEvent<T>>	forPayload(Consumer<T> consumer)	Create a new ApplicationListener for the given payload consumer.
void	onApplicationEvent(E event)	Handle an application event.
default boolean	supportsAsyncExecution()	Return whether this listener supports asynchronous execution.

Method Details

onApplicationEvent

void onApplicationEvent(E event)

Handle an application event.

Parameters:

event - the event to respond to

supportsAsyncExecution

default boolean supportsAsyncExecution()

Return whether this listener supports asynchronous execution.

Returns:

true if this listener instance can be executed asynchronously depending on the multicaster configuration (the default), or false if it needs to immediately run within the original thread which published the event

Since:

6.1

See Also:

• SimpleApplicationEventMulticaster.setTaskExecutor(java.util.concurrent.Executor)

forPayload

static <T>
ApplicationListener<PayloadApplicationEvent<T>> forPayload(Consumer<T> consumer)

Create a new ApplicationListener for the given payload consumer.

Type Parameters:

T - the type of the event payload

Parameters:

consumer - the event payload consumer

Returns:

a corresponding ApplicationListener instance

Since:

5.3

See Also:

• PayloadApplicationEvent