Bug 148626 [Regression]Can't fetch value from the filter of table/chart which inherites data from container
Steps: 1. create a table and bind a dataset in it 2. create another table/chart in the table detail/table group header 3. switch to the Filter tab in property editor 4. create a filter and select value in "<select value...>" combo 5. an error popuped up, "The expression value can't be retrieved"
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/ReportDataServiceProvider.java
if ( ChartUIUtil.getExpressionString( cc.getName( ) )
					.equals( expression ) )
			{
				String dataType = cc.getDataType( );
				if (  dataType.equals( DesignChoiceConstants.COLUMN_DATA_TYPE_STRING ) )
				{
					return DataType.TEXT_LITERAL;
				}
				else if ( dataType.equals( DesignChoiceConstants.COLUMN_DATA_TYPE_DECIMAL )
						|| dataType.equals( DesignChoiceConstants.COLUMN_DATA_TYPE_FLOAT )
						|| dataType.equals( DesignChoiceConstants.COLUMN_DATA_TYPE_INTEGER )
						|| dataType.equals( DesignChoiceConstants.COLUMN_DATA_TYPE_BOOLEAN ) )
				{
					return DataType.NUMERIC_LITERAL;
				}
				else if ( dataType.equals( DesignChoiceConstants.COLUMN_DATA_TYPE_DATETIME )
						|| dataType.equals( DesignChoiceConstants.COLUMN_DATA_TYPE_DATE ) 
						|| dataType.equals( DesignChoiceConstants.COLUMN_DATA_TYPE_TIME ) )
				{
					return DataType.DATE_TIME_LITERAL;
				}
				else if ( dataType.equals( DesignChoiceConstants.COLUMN_DATA_TYPE_ANY ) )
				{
					return null;
				}
			}
		}
		return null;		
	}
}