Package org.apache.commons.lang3.event
Class EventListenerSupport<L>
java.lang.Object
org.apache.commons.lang3.event.EventListenerSupport<L>
- Type Parameters:
L
- the type of event listener that is supported by this proxy.
- All Implemented Interfaces:
Serializable
Manages a list of event listeners of a given generic type. This class provides
addListener(Object)
and removeListener(Object)
methods for
managing listeners, as well as a fire()
method for firing events to the listeners.
For example, to support ActionEvents:
public class MyActionEventSource {
private EventListenerSupport<ActionListener> actionListeners = EventListenerSupport.create(ActionListener.class);
public void someMethodThatFiresAction() {
ActionEvent e = new ActionEvent(this, ActionEvent.ACTION_PERFORMED, "something");
actionListeners.fire().actionPerformed(e);
}
}
Events are fired
Serializing an EventListenerSupport
instance will result in any non-Serializable
listeners being silently dropped.
- Since:
- 3.0
- See Also:
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprotected class
Invokes listeners throughEventListenerSupport.ProxyInvocationHandler.invoke(Object, Method, Object[])
in the order added to the underlyingList
. -
Constructor Summary
ConstructorsConstructorDescriptionEventListenerSupport
(Class<L> listenerInterface) Constructs an EventListenerSupport object which supports the provided listener interface.EventListenerSupport
(Class<L> listenerInterface, ClassLoader classLoader) Constructs an EventListenerSupport object which supports the provided listener interface using the specified class loader to create the JDK dynamic proxy. -
Method Summary
Modifier and TypeMethodDescriptionvoid
addListener
(L listener) Adds an event listener.void
addListener
(L listener, boolean allowDuplicate) Adds an event listener.static <T> EventListenerSupport
<T> Creates an EventListenerSupport object which supports the specified listener type.protected InvocationHandler
Creates theInvocationHandler
responsible for calling to the managed listeners.fire()
Returns a proxy object which can be used to call listener methods on all of the registered event listeners.L[]
Gets an array containing the currently registered listeners.void
removeListener
(L listener) Removes an event listener.
-
Constructor Details
-
EventListenerSupport
Constructs an EventListenerSupport object which supports the provided listener interface.- Parameters:
listenerInterface
- the type of listener interface that will receive events posted using this class.- Throws:
NullPointerException
- iflistenerInterface
isnull
.IllegalArgumentException
- iflistenerInterface
is not an interface.
-
EventListenerSupport
Constructs an EventListenerSupport object which supports the provided listener interface using the specified class loader to create the JDK dynamic proxy.- Parameters:
listenerInterface
- the listener interface.classLoader
- the class loader.- Throws:
NullPointerException
- iflistenerInterface
orclassLoader
isnull
.IllegalArgumentException
- iflistenerInterface
is not an interface.
-
-
Method Details
-
create
Creates an EventListenerSupport object which supports the specified listener type.- Type Parameters:
T
- the type of the listener interface- Parameters:
listenerInterface
- the type of listener interface that will receive events posted using this class.- Returns:
- an EventListenerSupport object which supports the specified listener type.
- Throws:
NullPointerException
- iflistenerInterface
isnull
.IllegalArgumentException
- iflistenerInterface
is not an interface.
-
addListener
Adds an event listener.Listeners are called in the order added.
- Parameters:
listener
- the event listener (may not benull
).- Throws:
NullPointerException
- iflistener
isnull
.
-
addListener
Adds an event listener. Will not add a pre-existing listener object to the list ifallowDuplicate
is false.Listeners are called in the order added.
- Parameters:
listener
- the event listener (may not benull
).allowDuplicate
- the flag for determining if duplicate listener objects are allowed to be registered.- Throws:
NullPointerException
- iflistener
isnull
.- Since:
- 3.5
-
createInvocationHandler
Creates theInvocationHandler
responsible for calling to the managed listeners. Subclasses can override to provide custom behavior.- Returns:
- ProxyInvocationHandler
-
fire
Returns a proxy object which can be used to call listener methods on all of the registered event listeners. All calls made to this proxy will be forwarded to all registered listeners.- Returns:
- a proxy object which can be used to call listener methods on all of the registered event listeners
-
getListeners
Gets an array containing the currently registered listeners. Modification to this array's elements will have no effect on theEventListenerSupport
instance.- Returns:
- L[]
-
removeListener
Removes an event listener.- Parameters:
listener
- the event listener (may not benull
).- Throws:
NullPointerException
- iflistener
isnull
.
-