afreechart/src/main/java/org/afree/chart/AFreeChart.java
/**
     * Registers an object for notification of changes to the chart.
     *
     * @param listener  the listener (<code>null</code> not permitted).
     *
     * @see #removeChangeListener(ChartChangeListener)
     */
Registers an object for notification of changes to the chart.
@param listener  the listener (null not permitted).


Registers an object for notification of changes to the chart . @param listener the listener ( null not permitted ) .
public void addChangeListener(ChartChangeListener listener) {
        if (listener == null) {
            throw new IllegalArgumentException("Null 'listener' argument.");
        }
        this.changeListeners.add(listener);
    }
public void addChangeListener ( ChartChangeListener listener ) { if ( listener == null ) { throw new IllegalArgumentException ( "Null 'listener' argument." ) ; } this . changeListeners . add ( listener ) ; }
Registers an object for notification of changes to the chart.
Registers an object for notification of changes to the chart .