public void addCDKChangeListener(ICDKChangeListener listener) {
        if (listeners == null) {
            listeners = new ArrayList<ICDKChangeListener>();
        }
        if (!listeners.contains(listener)) {
            listeners.add(listener);
        }
    }
public void addCDKChangeListener ( ICDKChangeListener listener ) { if ( listeners == null ) { listeners = new ArrayList < ICDKChangeListener > ( ) ; } if ( ! listeners . contains ( listener ) ) { listeners . add ( listener ) ; } }
Adds a change listener to the list of listeners.

@param listener
The listener added to the list