Class PropertyChangeSupport
- All Implemented Interfaces:
Serializable
- Direct Known Subclasses:
SwingPropertyChangeSupport
PropertyChangeEvent
s to them. You can use an instance of this class
as a member field of your bean and delegate these types of work to it.
The PropertyChangeListener
can be registered for all properties
or for a property specified by name.
Here is an example of PropertyChangeSupport
usage that follows
the rules and recommendations laid out in the JavaBeans specification:
public class MyBean { private final PropertyChangeSupport pcs = new PropertyChangeSupport(this); public void addPropertyChangeListener(PropertyChangeListener listener) { this.pcs.addPropertyChangeListener(listener); } public void removePropertyChangeListener(PropertyChangeListener listener) { this.pcs.removePropertyChangeListener(listener); } private String value; public String getValue() { return this.value; } public void setValue(String newValue) { String oldValue = this.value; this.value = newValue; this.pcs.firePropertyChange("value", oldValue, newValue); } [...] }
A PropertyChangeSupport
instance is thread-safe.
This class is serializable. When it is serialized it will save (and restore) any listeners that are themselves serializable. Any non-serializable listeners will be skipped during serialization.
- Since:
- 1.1
- See Also:
-
Constructor Summary
ConstructorDescriptionPropertyChangeSupport
(Object sourceBean) Constructs aPropertyChangeSupport
object. -
Method Summary
Modifier and TypeMethodDescriptionvoid
Add a PropertyChangeListener to the listener list.void
addPropertyChangeListener
(String propertyName, PropertyChangeListener listener) Add a PropertyChangeListener for a specific property.void
fireIndexedPropertyChange
(String propertyName, int index, boolean oldValue, boolean newValue) Reports a boolean bound indexed property update to listeners that have been registered to track updates of all properties or a property with the specified name.void
fireIndexedPropertyChange
(String propertyName, int index, int oldValue, int newValue) Reports an integer bound indexed property update to listeners that have been registered to track updates of all properties or a property with the specified name.void
fireIndexedPropertyChange
(String propertyName, int index, Object oldValue, Object newValue) Reports a bound indexed property update to listeners that have been registered to track updates of all properties or a property with the specified name.void
Fires a property change event to listeners that have been registered to track updates of all properties or a property with the specified name.void
firePropertyChange
(String propertyName, boolean oldValue, boolean newValue) Reports a boolean bound property update to listeners that have been registered to track updates of all properties or a property with the specified name.void
firePropertyChange
(String propertyName, int oldValue, int newValue) Reports an integer bound property update to listeners that have been registered to track updates of all properties or a property with the specified name.void
firePropertyChange
(String propertyName, Object oldValue, Object newValue) Reports a bound property update to listeners that have been registered to track updates of all properties or a property with the specified name.Returns an array of all the listeners that were added to the PropertyChangeSupport object with addPropertyChangeListener().getPropertyChangeListeners
(String propertyName) Returns an array of all the listeners which have been associated with the named property.boolean
hasListeners
(String propertyName) Check if there are any listeners for a specific property, including those registered on all properties.void
Remove a PropertyChangeListener from the listener list.void
removePropertyChangeListener
(String propertyName, PropertyChangeListener listener) Remove a PropertyChangeListener for a specific property.
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Constructor Details
-
PropertyChangeSupport
Constructs aPropertyChangeSupport
object.- Parameters:
sourceBean
- The bean to be given as the source for any events.
-
-
Method Details
-
addPropertyChangeListener
Add a PropertyChangeListener to the listener list. The listener is registered for all properties. The same listener object may be added more than once, and will be called as many times as it is added. Iflistener
is null, no exception is thrown and no action is taken.- Parameters:
listener
- The PropertyChangeListener to be added
-
removePropertyChangeListener
Remove a PropertyChangeListener from the listener list. This removes a PropertyChangeListener that was registered for all properties. Iflistener
was added more than once to the same event source, it will be notified one less time after being removed. Iflistener
is null, or was never added, no exception is thrown and no action is taken.- Parameters:
listener
- The PropertyChangeListener to be removed
-
getPropertyChangeListeners
Returns an array of all the listeners that were added to the PropertyChangeSupport object with addPropertyChangeListener().If some listeners have been added with a named property, then the returned array will be a mixture of PropertyChangeListeners and
PropertyChangeListenerProxy
s. If the calling method is interested in distinguishing the listeners then it must test each element to see if it's aPropertyChangeListenerProxy
, perform the cast, and examine the parameter.PropertyChangeListener[] listeners = bean.getPropertyChangeListeners(); for (int i = 0; i < listeners.length; i++) { if (listeners[i] instanceof PropertyChangeListenerProxy) { PropertyChangeListenerProxy proxy = (PropertyChangeListenerProxy)listeners[i]; if (proxy.getPropertyName().equals("foo")) { // proxy is a PropertyChangeListener which was associated // with the property named "foo" } } }
- Returns:
- all of the
PropertyChangeListeners
added or an empty array if no listeners have been added - Since:
- 1.4
- See Also:
-
addPropertyChangeListener
Add a PropertyChangeListener for a specific property. The listener will be invoked only when a call on firePropertyChange names that specific property. The same listener object may be added more than once. For each property, the listener will be invoked the number of times it was added for that property. IfpropertyName
orlistener
is null, no exception is thrown and no action is taken.- Parameters:
propertyName
- The name of the property to listen on.listener
- The PropertyChangeListener to be added- Since:
- 1.2
-
removePropertyChangeListener
Remove a PropertyChangeListener for a specific property. Iflistener
was added more than once to the same event source for the specified property, it will be notified one less time after being removed. IfpropertyName
is null, no exception is thrown and no action is taken. Iflistener
is null, or was never added for the specified property, no exception is thrown and no action is taken.- Parameters:
propertyName
- The name of the property that was listened on.listener
- The PropertyChangeListener to be removed- Since:
- 1.2
-
getPropertyChangeListeners
Returns an array of all the listeners which have been associated with the named property.- Parameters:
propertyName
- The name of the property being listened to- Returns:
- all of the
PropertyChangeListeners
associated with the named property. If no such listeners have been added, or ifpropertyName
is null, an empty array is returned. - Since:
- 1.4
-
firePropertyChange
Reports a bound property update to listeners that have been registered to track updates of all properties or a property with the specified name.No event is fired if old and new values are equal and non-null.
This is merely a convenience wrapper around the more general
firePropertyChange(PropertyChangeEvent)
method.- Parameters:
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the propertynewValue
- the new value of the property
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firePropertyChange
Reports an integer bound property update to listeners that have been registered to track updates of all properties or a property with the specified name.No event is fired if old and new values are equal.
This is merely a convenience wrapper around the more general
firePropertyChange(String, Object, Object)
method.- Parameters:
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the propertynewValue
- the new value of the property- Since:
- 1.2
-
firePropertyChange
Reports a boolean bound property update to listeners that have been registered to track updates of all properties or a property with the specified name.No event is fired if old and new values are equal.
This is merely a convenience wrapper around the more general
firePropertyChange(String, Object, Object)
method.- Parameters:
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the propertynewValue
- the new value of the property- Since:
- 1.2
-
firePropertyChange
Fires a property change event to listeners that have been registered to track updates of all properties or a property with the specified name.No event is fired if the given event's old and new values are equal and non-null.
- Parameters:
event
- thePropertyChangeEvent
to be fired- Since:
- 1.2
-
fireIndexedPropertyChange
public void fireIndexedPropertyChange(String propertyName, int index, Object oldValue, Object newValue) Reports a bound indexed property update to listeners that have been registered to track updates of all properties or a property with the specified name.No event is fired if old and new values are equal and non-null.
This is merely a convenience wrapper around the more general
firePropertyChange(PropertyChangeEvent)
method.- Parameters:
propertyName
- the programmatic name of the property that was changedindex
- the index of the property element that was changedoldValue
- the old value of the propertynewValue
- the new value of the property- Since:
- 1.5
-
fireIndexedPropertyChange
Reports an integer bound indexed property update to listeners that have been registered to track updates of all properties or a property with the specified name.No event is fired if old and new values are equal.
This is merely a convenience wrapper around the more general
fireIndexedPropertyChange(String, int, Object, Object)
method.- Parameters:
propertyName
- the programmatic name of the property that was changedindex
- the index of the property element that was changedoldValue
- the old value of the propertynewValue
- the new value of the property- Since:
- 1.5
-
fireIndexedPropertyChange
public void fireIndexedPropertyChange(String propertyName, int index, boolean oldValue, boolean newValue) Reports a boolean bound indexed property update to listeners that have been registered to track updates of all properties or a property with the specified name.No event is fired if old and new values are equal.
This is merely a convenience wrapper around the more general
fireIndexedPropertyChange(String, int, Object, Object)
method.- Parameters:
propertyName
- the programmatic name of the property that was changedindex
- the index of the property element that was changedoldValue
- the old value of the propertynewValue
- the new value of the property- Since:
- 1.5
-
hasListeners
Check if there are any listeners for a specific property, including those registered on all properties. IfpropertyName
is null, only check for listeners registered on all properties.- Parameters:
propertyName
- the property name.- Returns:
- true if there are one or more listeners for the given property
- Since:
- 1.2
-