Added a way for contacts to notify when they change properties (such as the display name)

src/net/java/sip/communicator/service/protocol/event/ContactPropertyChangeEvent.java

@@ -0,0 +1,49 @@
+package net.java.sip.communicator.service.protocol.event;
+
+import net.java.sip.communicator.service.protocol.*;
+
+/**
+ * A Contact property change event is issued whenever a contact property has
+ * changed. Event codes defined in this class describe properties whose changes
+ * are being announced through this event.
+ *
+ * @author Emil Ivov
+ */
+public class ContactPropertyChangeEvent
+    extends java.beans.PropertyChangeEvent
+{
+    /**
+     * Indicates that a change has occurred in the display name of the source
+     * contact.
+     */
+    public static final String PROPERTY_DISPLAY_NAME = "DisplayName";
+
+    /**
+     * Creates a ContactPropertyChangeEvent indicating that a change has
+     * occurred for property <tt>propertyName</tt> in the <tt>source</tt>
+     * contact and that its value has changed from <tt>oldValue</tt> to
+     * <tt>newValue</tt>.
+     * <p>
+     * @param source the Contact whose property has changed.
+     * @param propertyName the name of the property that has changed.
+     * @param oldValue the value of the property before the change occurred.
+     * @param newValue the value of the property after the change occurred.
+     */
+    public ContactPropertyChangeEvent( Contact source,
+                                       String  propertyName,
+                                       Object  oldValue,
+                                       Object  newValue)
+    {
+        super(source, propertyName, oldValue, newValue);
+    }
+
+    /**
+     * Returns a reference to the <tt>Contact</tt> whose property has changed.
+     * <p>
+     * @return a reference to the <tt>Contact</tt> whose reference has changed.
+     */
+    public Contact getSourceContact()
+    {
+        return (Contact)getSource();
+    }
+}