java / beginner
Snippet
Processing Domain Events Asynchronously with EventListener
Spring supports the Observer pattern through application events. Combining @EventListener with @Async allows event consumers to process events in a separate worker thread. This prevents long-running operations—such as sending registration emails—from blocking the main request thread.
snippet.java
java
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@Componentpublic class UserNotificationListener {@Async@EventListenerpublic void handleUserRegistration(UserRegisteredEvent event) {String userEmail = event.getEmail();System.out.println("Sending asynchronous confirmation email to: " + userEmail);}}
spring
Breakdown
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@Component
Registers this listener class as a Spring bean so that event listeners can be discovered.
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@Async
Directs Spring to execute this listener method in a separate background thread pool.
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@EventListener
Registers this method to be invoked whenever a matching event type is published.
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public void handleUserRegistration(UserRegisteredEvent event) {
Defines the event payload type (UserRegisteredEvent) that triggers this listener.