Returns a method or function that will be used to collect mime data \
        for a list of tablewidgetitems.  If set, the method should accept a \
        single argument for a list of items and then return a QMimeData \
        instance.
        
        :usage      |from projexui.qt.QtCore import QMimeData, QWidget
                    |from projexui.widgets.xtablewidget import XTableWidget
                    |
                    |def collectData(table, items):
                    |   data = QMimeData()
                    |   data.setText(','.join(map(lambda x: x.text(0), items)))
                    |   return data
                    |
                    |class MyWidget(QWidget):
                    |   def __init__( self, parent ):
                    |       super(MyWidget, self).__init__(parent)
                    |       
                    |       self._table = XTableWidget(self)
                    |       self._table.setDataCollector(collectData)
                    
        
        :return     <function> || <method> || None

def dataCollector( self ):
        """
        Returns a method or function that will be used to collect mime data \
        for a list of tablewidgetitems.  If set, the method should accept a \
        single argument for a list of items and then return a QMimeData \
        instance.
        
        :usage      |from projexui.qt.QtCore import QMimeData, QWidget
                    |from projexui.widgets.xtablewidget import XTableWidget
                    |
                    |def collectData(table, items):
                    |   data = QMimeData()
                    |   data.setText(','.join(map(lambda x: x.text(0), items)))
                    |   return data
                    |
                    |class MyWidget(QWidget):
                    |   def __init__( self, parent ):
                    |       super(MyWidget, self).__init__(parent)
                    |       
                    |       self._table = XTableWidget(self)
                    |       self._table.setDataCollector(collectData)
                    
        
        :return     <function> || <method> || None
        """
        func = None
        if ( self._dataCollectorRef ):
            func = self._dataCollectorRef()
        
        if ( not func ):
            self._dataCollectorRef = None
        
        return func