Package org.apache.cayenne.event
Interface EventManager
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- All Known Implementing Classes:
DefaultEventManager,NoopEventManager
public interface EventManagerThis class acts as bridge between an Object that wants to inform others about its current state or a change thereof (Publisher) and a list of objects interested in the Subject (Listeners).- Since:
- 3.1 before 3.1 this was a concrete class.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description voidaddListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject)Register anEventListenerfor events sent by any sender.voidaddListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject, Object sender)Register anEventListenerfor events sent by a specific sender.voidaddNonBlockingListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject)voidaddNonBlockingListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject, Object sender)booleanisSingleThreaded()Returns true if this EventManager is single-threaded.voidpostEvent(EventObject event, EventSubject subject)Sends an event to all registered objects about a particular subject.voidpostNonBlockingEvent(EventObject event, EventSubject subject)Sends an event to all registered objects about a particular subject.booleanremoveAllListeners(EventSubject subject)Removes all listeners for a given subject.booleanremoveListener(Object listener)Unregister the specified listener from all event subjects handled by this manager instance.booleanremoveListener(Object listener, EventSubject subject)Unregister the specified listener for the events about the given subject.booleanremoveListener(Object listener, EventSubject subject, Object sender)Unregister the specified listener for the events about the given subject and the given sender.
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Method Detail
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isSingleThreaded
boolean isSingleThreaded()
Returns true if this EventManager is single-threaded. If so it will throw an exception on any attempt to register an unblocking listener or dispatch a non-blocking event.- Since:
- 1.2
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addListener
void addListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject)
Register anEventListenerfor events sent by any sender.- Throws:
RuntimeException- ifmethodNameis not found.
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addNonBlockingListener
void addNonBlockingListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject)
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addListener
void addListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject, Object sender)
Register anEventListenerfor events sent by a specific sender.- Parameters:
listener- the object to be notified about eventsmethodName- the name of the listener method to be invokedeventParameterClass- the class of the single event argument passed tomethodNamesubject- the event subject that the listener is interested insender- the object whose events the listener is interested in;nullmeans 'any sender'.- Throws:
RuntimeException- ifmethodNameis not found
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addNonBlockingListener
void addNonBlockingListener(Object listener, String methodName, Class<?> eventParameterClass, EventSubject subject, Object sender)
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removeListener
boolean removeListener(Object listener)
Unregister the specified listener from all event subjects handled by this manager instance.- Parameters:
listener- the object to be unregistered- Returns:
trueiflistenercould be removed for any existing subjects, else returnsfalse.
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removeAllListeners
boolean removeAllListeners(EventSubject subject)
Removes all listeners for a given subject.
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removeListener
boolean removeListener(Object listener, EventSubject subject)
Unregister the specified listener for the events about the given subject.- Parameters:
listener- the object to be unregisteredsubject- the subject from which the listener is to be unregistered- Returns:
trueiflistenercould be removed for the given subject, else returnsfalse.
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removeListener
boolean removeListener(Object listener, EventSubject subject, Object sender)
Unregister the specified listener for the events about the given subject and the given sender.- Parameters:
listener- the object to be unregisteredsubject- the subject from which the listener is to be unregisteredsender- the object whose events the listener was interested in;nullmeans 'any sender'.- Returns:
trueiflistenercould be removed for the given subject, else returnsfalse.
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postEvent
void postEvent(EventObject event, EventSubject subject)
Sends an event to all registered objects about a particular subject. Event is sent synchronously, so the sender thread is blocked until all the listeners finish processing the event.- Parameters:
event- the event to be posted to the observerssubject- the subject about which observers will be notified- Throws:
IllegalArgumentException- if event or subject are null
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postNonBlockingEvent
void postNonBlockingEvent(EventObject event, EventSubject subject)
Sends an event to all registered objects about a particular subject. Event is queued by EventManager, releasing the sender thread, and is later dispatched in a separate thread.- Parameters:
event- the event to be posted to the observerssubject- the subject about which observers will be notified- Throws:
IllegalArgumentException- if event or subject are null- Since:
- 1.1
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