afreechart/src/main/java/org/afree/data/xy/VectorSeriesCollection.java
/**
     * Returns the index of the specified series, or -1 if that series is not
     * present in the dataset.
     *
     * @param series  the series (<code>null</code> not permitted).
     *
     * @return The series index.
     */
Returns the index of the specified series, or -1 if that series is not
present in the dataset.

@param series  the series (null not permitted).

@return The series index.
Returns the index of the specified series or - 1 if that series is not present in the dataset . @param series the series ( null not permitted ) . @return The series index .
public int indexOf(VectorSeries series) {
        if (series == null) {
            throw new IllegalArgumentException("Null 'series' argument.");
        }
        return this.data.indexOf(series);
    }
public int indexOf ( VectorSeries series ) { if ( series == null ) { throw new IllegalArgumentException ( "Null 'series' argument." ) ; } return this . data . indexOf ( series ) ; }
Returns the index of the specified series, or -1 if that series is not
 present in the dataset.
Returns the index of the specified series or - 1 if that series is not present in the dataset .