private Object resolveRowData() {
        if (source instanceof PrimeUIData) {
            DataTable data = (DataTable) source;
            data.setRowModel(rowIndex);
            return data.getRowData();
        }
        else if (source instanceof UITree) {
            TreeTable data = (TreeTable) source;
            data.setRowKey(data.getValue(), rowKey);
            return data.getRowNode();
        }
        return null;
    }
Data contained in the DataTable row or TreeTable node.
primefaces/src/main/java/org/primefaces/event/CellEditEvent.java