com.vaadin.flow.component

Class ComponentEventBus

java.lang.Object

com.vaadin.flow.component.ComponentEventBus

All Implemented Interfaces:

Serializable

public class ComponentEventBus
extends Object
implements Serializable

An event bus for Components.

Handles adding and removing event listeners, and firing events of type ComponentEvent.

Events can either be fired manually through fireEvent(ComponentEvent) or automatically based on a DOM event (see @DomEvent). Automatically fired events must have a suitable constructor, as defined in DomEvent.

Since:

1.0

Author:

Vaadin Ltd

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ComponentEventBus(Component component) Creates an event bus for the given component.

Method Summary

Modifier and Type	Method and Description
<T extends ComponentEvent<?>> Registration	addListener(Class<T> eventType, ComponentEventListener<T> listener) Adds a listener for the given event type.
void	fireEvent(ComponentEvent event) Dispatches the event to all listeners registered for the event type.
boolean	hasListener(Class<? extends ComponentEvent> eventType) Checks if there is at least one listener registered for the given event type.

Methods inherited from class java.lang.Object

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

Constructor Detail

ComponentEventBus

public ComponentEventBus(Component component)

Creates an event bus for the given component.

Parameters:

component - the component which will be used as a source for all fired events

Method Detail

addListener

public <T extends ComponentEvent<?>> Registration addListener(Class<T> eventType,
                                                              ComponentEventListener<T> listener)

Adds a listener for the given event type.

Type Parameters:

T - the event type

Parameters:

eventType - the event type for which to call the listener

listener - the listener to call when the event occurs

Returns:

an object which can be used to remove the event listener

hasListener

public boolean hasListener(Class<? extends ComponentEvent> eventType)

Checks if there is at least one listener registered for the given event type.

Parameters:

eventType - the component event type

Returns:

true if at least one listener is registered, false otherwise

fireEvent

public void fireEvent(ComponentEvent event)

Dispatches the event to all listeners registered for the event type.

Parameters:

event - the event to fire