Serializable
public class VetoableChangeSupport 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 VetoableChangeListener
can be registered for all properties or for a property specified by name. Here is an example of VetoableChangeSupport
usage that follows the rules and recommendations laid out in the JavaBeans specification:
public class MyBean {
private final VetoableChangeSupport vcs = new VetoableChangeSupport(this);
public void addVetoableChangeListener(VetoableChangeListener listener) {
this.vcs.addVetoableChangeListener(listener);
}
public void removeVetoableChangeListener(VetoableChangeListener listener) {
this.vcs.removeVetoableChangeListener(listener);
}
private String value;
public String getValue() {
return this.value;
}
public void setValue(String newValue) throws PropertyVetoException {
String oldValue = this.value;
this.vcs.fireVetoableChange("value", oldValue, newValue);
this.value = newValue;
}
[...]
}
A VetoableChangeSupport
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.
Constructor | Description |
---|---|
VetoableChangeSupport |
Constructs a VetoableChangeSupport object. |
Modifier and Type | Method | Description |
---|---|---|
void |
addVetoableChangeListener |
Add a VetoableChangeListener to the listener list. |
void |
addVetoableChangeListener |
Add a VetoableChangeListener for a specific property. |
void |
fireVetoableChange |
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 |
fireVetoableChange |
Reports a boolean constrained property update to listeners that have been registered to track updates of all properties or a property with the specified name. |
void |
fireVetoableChange |
Reports an integer constrained property update to listeners that have been registered to track updates of all properties or a property with the specified name. |
void |
fireVetoableChange |
Reports a constrained property update to listeners that have been registered to track updates of all properties or a property with the specified name. |
VetoableChangeListener[] |
getVetoableChangeListeners() |
Returns an array of all the listeners that were added to the VetoableChangeSupport object with addVetoableChangeListener(). |
VetoableChangeListener[] |
getVetoableChangeListeners |
Returns an array of all the listeners which have been associated with the named property. |
boolean |
hasListeners |
Check if there are any listeners for a specific property, including those registered on all properties. |
void |
removeVetoableChangeListener |
Remove a VetoableChangeListener from the listener list. |
void |
removeVetoableChangeListener |
Remove a VetoableChangeListener for a specific property. |
public VetoableChangeSupport(Object sourceBean)
VetoableChangeSupport
object.sourceBean
- The bean to be given as the source for any events.public void addVetoableChangeListener(VetoableChangeListener listener)
listener
is null, no exception is thrown and no action is taken.listener
- The VetoableChangeListener to be addedpublic void removeVetoableChangeListener(VetoableChangeListener 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 VetoableChangeListener to be removedpublic VetoableChangeListener[] getVetoableChangeListeners()
If some listeners have been added with a named property, then the returned array will be a mixture of VetoableChangeListeners and VetoableChangeListenerProxy
s. If the calling method is interested in distinguishing the listeners then it must test each element to see if it's a VetoableChangeListenerProxy
, perform the cast, and examine the parameter.
VetoableChangeListener[] listeners = bean.getVetoableChangeListeners();
for (int i = 0; i < listeners.length; i++) {
if (listeners[i] instanceof VetoableChangeListenerProxy) {
VetoableChangeListenerProxy proxy =
(VetoableChangeListenerProxy)listeners[i];
if (proxy.getPropertyName().equals("foo")) {
// proxy is a VetoableChangeListener which was associated
// with the property named "foo"
}
}
}
VetoableChangeListeners
added or an empty array if no listeners have been addedpublic void addVetoableChangeListener(String propertyName, VetoableChangeListener 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 VetoableChangeListener to be addedpublic void removeVetoableChangeListener(String propertyName, VetoableChangeListener 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 VetoableChangeListener to be removedpublic VetoableChangeListener[] getVetoableChangeListeners(String propertyName)
propertyName
- The name of the property being listened toVetoableChangeListeners
associated with the named property. If no such listeners have been added, or if propertyName
is null, an empty array is returned.public void fireVetoableChange(String propertyName, Object oldValue, Object newValue) throws PropertyVetoException
Any listener can throw a PropertyVetoException
to veto the update. If one of the listeners vetoes the update, this method passes a new "undo" PropertyChangeEvent
that reverts to the old value to all listeners that already confirmed this update and throws the PropertyVetoException
again.
No event is fired if old and new values are equal and non-null.
This is merely a convenience wrapper around the more general fireVetoableChange(PropertyChangeEvent)
method.
propertyName
- the programmatic name of the property that is about to changeoldValue
- the old value of the propertynewValue
- the new value of the propertyPropertyVetoException
- if one of listeners vetoes the property updatepublic void fireVetoableChange(String propertyName, int oldValue, int newValue) throws PropertyVetoException
Any listener can throw a PropertyVetoException
to veto the update. If one of the listeners vetoes the update, this method passes a new "undo" PropertyChangeEvent
that reverts to the old value to all listeners that already confirmed this update and throws the PropertyVetoException
again.
No event is fired if old and new values are equal.
This is merely a convenience wrapper around the more general fireVetoableChange(String, Object, Object)
method.
propertyName
- the programmatic name of the property that is about to changeoldValue
- the old value of the propertynewValue
- the new value of the propertyPropertyVetoException
- if one of listeners vetoes the property updatepublic void fireVetoableChange(String propertyName, boolean oldValue, boolean newValue) throws PropertyVetoException
Any listener can throw a PropertyVetoException
to veto the update. If one of the listeners vetoes the update, this method passes a new "undo" PropertyChangeEvent
that reverts to the old value to all listeners that already confirmed this update and throws the PropertyVetoException
again.
No event is fired if old and new values are equal.
This is merely a convenience wrapper around the more general fireVetoableChange(String, Object, Object)
method.
propertyName
- the programmatic name of the property that is about to changeoldValue
- the old value of the propertynewValue
- the new value of the propertyPropertyVetoException
- if one of listeners vetoes the property updatepublic void fireVetoableChange(PropertyChangeEvent event) throws PropertyVetoException
Any listener can throw a PropertyVetoException
to veto the update. If one of the listeners vetoes the update, this method passes a new "undo" PropertyChangeEvent
that reverts to the old value to all listeners that already confirmed this update and throws the PropertyVetoException
again.
No event is fired if the given event's old and new values are equal and non-null.
event
- the PropertyChangeEvent
to be firedPropertyVetoException
- if one of listeners vetoes the property updatepublic boolean hasListeners(String propertyName)
propertyName
is null, only check for listeners registered on all properties.propertyName
- the property name.
© 1993, 2023, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/java/beans/VetoableChangeSupport.html