public int getRowIndex() {

        return (Integer) getStateHelper().eval(PropertyKeys.rowIndex, -1);

    }
<p>Return the zero-relative index of the currently selected row.  If we
are not currently positioned on a row, return -1.  This property is
<strong>not</strong> enabled for value binding expressions.</p>

@return the row index.

@throws FacesException if an error occurs getting the row index
primefaces/src/main/java/org/primefaces/component/patch/UIDataPatch.java