Package org.apache.fop.events
Interface EventBroadcaster
- All Known Implementing Classes:
DefaultEventBroadcaster
,FOUserAgent.FOPEventBroadcaster
public interface EventBroadcaster
The EventBroadcaster is the central relay point for events. It receives events from various
parts of the application and forwards them to any registered EventListener.
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Method Summary
Modifier and TypeMethodDescriptionvoid
addEventListener
(EventListener listener) Adds an event listener to the broadcaster.void
broadcastEvent
(Event event) Broadcasts an event.<T extends EventProducer>
TgetEventProducerFor
(Class<T> clazz) Returns an event producer instance for the given interface class.boolean
Indicates whether any listeners have been registered with the broadcaster.void
removeEventListener
(EventListener listener) Removes an event listener from the broadcaster.
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Method Details
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addEventListener
Adds an event listener to the broadcaster. It is appended to the list of previously registered listeners (the order of registration defines the calling order).- Parameters:
listener
- the listener to be added
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removeEventListener
Removes an event listener from the broadcaster. If the event listener is not registered, nothing happens.- Parameters:
listener
- the listener to be removed
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hasEventListeners
boolean hasEventListeners()Indicates whether any listeners have been registered with the broadcaster.- Returns:
- true if listeners are present, false otherwise
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broadcastEvent
Broadcasts an event. This method is usually called from within the observed component.- Parameters:
event
- the event to be broadcast
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getEventProducerFor
Returns an event producer instance for the given interface class.- Parameters:
clazz
- the Class object identifying anEventProducer
interface- Returns:
- the event producer instance
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