This Level 3 interface defines a handler that is invoked when a node on which user-specified data has been registered is adopted, cloned, deleted, imported or renamed. Register an object that implements this interface in the call to Node.setUserData( ).

public interface UserDataHandler {
// Public Constants
     public static final short NODE_ADOPTED;                             =5
     public static final short NODE_CLONED;                              =1
     public static final short NODE_DELETED;                             =3
     public static final short NODE_IMPORTED;                            =2
     public static final short NODE_RENAMED;                             =4
// Public Instance Methods
     void handle(short operation, String key, Object data, Node src, Node dst);  
}

Passed To

Node.setUserData( )