Package org.openstreetmap.josm.tools

Class ListenerList<T>

java.lang.Object

org.openstreetmap.josm.tools.ListenerList<T>

Type Parameters:

T - The type of listener contained in this list.

Direct Known Subclasses:

ListenerList.TracingListenerList, ListenerList.UncheckedListenerList

public class ListenerList<T>
extends java.lang.Object

This is a list of listeners. It does error checking and allows you to fire all listeners.

Since:

10824

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	ListenerList.EventFirerer<T>	This is a function that can be invoked for every listener.
static class	ListenerList.TracingListenerList<T>	This is a special ListenerList that traces calls to the add/remove methods.
private static class	ListenerList.UncheckedListenerList<T>
private static class	ListenerList.WeakListener<T>

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.concurrent.CopyOnWriteArrayList<T>	listeners
private java.util.concurrent.CopyOnWriteArrayList<ListenerList.WeakListener<T>>	weakListeners

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ListenerList()

Method Summary

Modifier and Type	Method	Description
void	addListener(T listener)	Adds a listener.
void	addWeakListener(T listener)	Adds a listener.
boolean	containsListener(T listener)	Determines if this listener list contains the given listener.
static <T> ListenerList<T>	create()	Create a new listener list
static <T> ListenerList<T>	createUnchecked()	Creates a new listener list that does not fail if listeners are added or removed twice.
private boolean	ensureNotInList(T listener)
protected void	failAdd(T listener)
protected void	failRemove(T listener)
void	fireEvent(ListenerList.EventFirerer<T> eventFirerer)	Fires an event to every listener.
boolean	hasListeners()	Check if any listeners are registered.
void	removeListener(T listener)	Removes a listener.

Methods inherited from class java.lang.Object

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

Field Detail

listeners

private final java.util.concurrent.CopyOnWriteArrayList<T> listeners

weakListeners

private final java.util.concurrent.CopyOnWriteArrayList<ListenerList.WeakListener<T>> weakListeners

Constructor Detail

ListenerList

protected ListenerList()

Method Detail

addWeakListener

public void addWeakListener(T listener)

Adds a listener. The listener will not prevent the object from being garbage collected.

This should be used with care. It is better to add good cleanup code.

Parameters:

listener - The listener.

addListener

public void addListener(T listener)

Adds a listener.

Parameters:

listener - The listener to add.

ensureNotInList

private boolean ensureNotInList(T listener)

failAdd

protected void failAdd(T listener)

containsListener

public boolean containsListener(T listener)

Determines if this listener list contains the given listener.

Parameters:

listener - listener to find

Returns:

true is the listener is known

Since:

15649

removeListener

public void removeListener(T listener)

Removes a listener.

Parameters:

listener - The listener to remove.

Throws:

java.lang.IllegalArgumentException - if the listener was not registered before

failRemove

protected void failRemove(T listener)

hasListeners

public boolean hasListeners()

Check if any listeners are registered.

Returns:

true if any are registered.

fireEvent

public void fireEvent(ListenerList.EventFirerer<T> eventFirerer)

Fires an event to every listener.

Parameters:

eventFirerer - The firerer to invoke the event method of the listener.

create

public static <T> ListenerList<T> create()

Create a new listener list

Type Parameters:

T - The listener type the list should hold.

Returns:

A new list. A tracing list is created if trace is enabled.

createUnchecked

public static <T> ListenerList<T> createUnchecked()

Creates a new listener list that does not fail if listeners are added or removed twice.

Use of this list is discouraged. You should always use create() in new implementations and check your listeners.

Type Parameters:

T - The listener type

Returns:

A new list.

Since:

11224