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Class com.ibm.beans.dip.VetoableChangeSupport

java.lang.Object
   |
   +----com.ibm.beans.dip.VetoableChangeSupport

public class VetoableChangeSupport
extends Object
implements Serializable
This utility class is based on java.beans.VetoableChangeSupport. The main difference between java.beans.VetoableChangeSupport and this class is that this class supports using com.ibm.beans.util.Collections to hold the listeners instead of being hardcoded to use only a Vector. Also, the isEmpty() and elements() methods were added to this class to allow the user to see which listeners were added.

See Also:
VetoableChangeSupport

Constructor Index

 o VetoableChangeSupport(Object)
Constructs a VetoableChangeSupport instance using the default Vector implementation.
 o VetoableChangeSupport(Object, Collection)
Constructs a VetoableChangeSupport instance using the input Collection.

Method Index

 o addVetoableChangeListener(VetoableChangeListener)
Adds a VetoableChangeListener to instance the listener list.
 o elements()
Gets an enumeration of VetoableChangeListener instances.
 o fireVetoableChange(String, Object, Object)
Reports a vetoable property update to any registered listeners.
 o isEmpty()
Checks to see if the collection of listeners is empty.
 o removeVetoableChangeListener(VetoableChangeListener)
Removes a VetoableChangeListener instance from the listener list.

Constructors

 o VetoableChangeSupport
 public VetoableChangeSupport(Object sourceBean)
Constructs a VetoableChangeSupport instance using the default Vector implementation.

Parameters:
sourceBean - The bean given as the source for any event.
 o VetoableChangeSupport
 public VetoableChangeSupport(Object sourceBean,
                              Collection collection)
Constructs a VetoableChangeSupport instance using the input Collection.

Parameters:
sourceBean - The bean given as the source for any event.
collection - The Collection used to store the listeners.

Methods

 o addVetoableChangeListener
 public synchronized void addVetoableChangeListener(VetoableChangeListener listener)
Adds a VetoableChangeListener to instance the listener list.

Parameters:
listener - The listener to add.
 o removeVetoableChangeListener
 public synchronized void removeVetoableChangeListener(VetoableChangeListener listener)
Removes a VetoableChangeListener instance from the listener list.

Parameters:
listener - The listener to remove.
 o fireVetoableChange
 public void fireVetoableChange(String propertyName,
                                Object oldValue,
                                Object newValue) throws PropertyVetoException
Reports a vetoable property update to any registered listeners. If anyone vetos the change, this method fires a new event reverting everyone to the old value and then rethrows the PropertyVetoException.

No event is fired if old and new are equal and non-null.

Parameters:
propertyName - The programmatic name of the changed property
oldValue - The old value of the property.
newValue - The new value of the property.
Throws: PropertyVetoException
May be thown if the listener wants the property change to be canceled.
 o elements
 public final synchronized Enumeration elements()
Gets an enumeration of VetoableChangeListener instances. Use the Enumeration methods on the returned object to fetch the elements sequentially.

Returns:
An enumeration of the listeners that will be fired in the fireVetoableChange() method.
 o isEmpty
 public final boolean isEmpty()
Checks to see if the collection of listeners is empty.

Returns:
true if empty; false otherwise.

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