public class PropertyChangeSupport extends Object implements Serializable
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.
VetoableChangeSupport
,
Serialized FormConstructor and Description |
---|
PropertyChangeSupport(Object sourceBean)
Constructs a
PropertyChangeSupport object. |
Modifier and Type | Method and Description |
---|---|
void |
addPropertyChangeListener(PropertyChangeListener listener)
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 |
firePropertyChange(PropertyChangeEvent event)
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.
|
PropertyChangeListener[] |
getPropertyChangeListeners()
Returns an array of all the listeners that were added to the
PropertyChangeSupport object with addPropertyChangeListener().
|
PropertyChangeListener[] |
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 |
removePropertyChangeListener(PropertyChangeListener listener)
Remove a PropertyChangeListener from the listener list.
|
void |
removePropertyChangeListener(String propertyName,
PropertyChangeListener listener)
Remove a PropertyChangeListener for a specific property.
|
public PropertyChangeSupport(Object sourceBean)
PropertyChangeSupport
object.sourceBean
- The bean to be given as the source for any events.public void addPropertyChangeListener(PropertyChangeListener listener)
listener
is null, no exception is thrown and no action
is taken.listener
- The PropertyChangeListener to be addedpublic void removePropertyChangeListener(PropertyChangeListener listener)
listener
was added more than once to the same event
source, it will be notified one less time after being removed.
If listener
is null, or was never added, no exception is
thrown and no action is taken.listener
- The PropertyChangeListener to be removedpublic PropertyChangeListener[] getPropertyChangeListeners()
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 a
PropertyChangeListenerProxy
, 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" } } }
PropertyChangeListeners
added or an
empty array if no listeners have been addedPropertyChangeListenerProxy
public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
propertyName
or listener
is null, no
exception is thrown and no action is taken.propertyName
- The name of the property to listen on.listener
- The PropertyChangeListener to be addedpublic void removePropertyChangeListener(String propertyName, PropertyChangeListener listener)
listener
was added more than once to the same event
source for the specified property, it will be notified one less time
after being removed.
If propertyName
is null, no exception is thrown and no
action is taken.
If listener
is null, or was never added for the specified
property, no exception is thrown and no action is taken.propertyName
- The name of the property that was listened on.listener
- The PropertyChangeListener to be removedpublic PropertyChangeListener[] getPropertyChangeListeners(String propertyName)
propertyName
- The name of the property being listened toPropertyChangeListeners
associated with
the named property. If no such listeners have been added,
or if propertyName
is null, an empty array is
returned.public void firePropertyChange(String propertyName, Object oldValue, Object newValue)
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.
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the propertynewValue
- the new value of the propertypublic void firePropertyChange(String propertyName, int oldValue, int newValue)
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.
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the propertynewValue
- the new value of the propertypublic void firePropertyChange(String propertyName, boolean oldValue, boolean newValue)
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.
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the propertynewValue
- the new value of the propertypublic void firePropertyChange(PropertyChangeEvent event)
No event is fired if the given event's old and new values are equal and non-null.
event
- the PropertyChangeEvent
to be firedpublic void fireIndexedPropertyChange(String propertyName, int index, Object oldValue, Object newValue)
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.
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 propertypublic void fireIndexedPropertyChange(String propertyName, int index, int oldValue, int newValue)
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.
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 propertypublic void fireIndexedPropertyChange(String propertyName, int index, boolean oldValue, boolean newValue)
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.
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 propertypublic boolean hasListeners(String propertyName)
propertyName
is null, only check for listeners registered on all properties.propertyName
- the property name. Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2013, Oracle and/or its affiliates. All rights reserved.