Bug 135465 [smoke]An error occurred when new a casading Parameter
Description: An error occurred when new a casading Parameter Step to reproduce: 1.new a sample db data source and data set 2.New a cascading parameter group, named "gp1", 3.select the data set, then create two cascading parameters, one is row["customernumber"], named p1; the other is row["customername"] Actual result; error message occurred repeatly
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
if ( formatString != null )
		{
			return formatString.split( ":" )[0]; 
		}
		return null;
	}
	private String getPattern( String formatString )
	{
		if ( formatString != null )
		{
			int index = formatString.indexOf( ':' ); 
			if ( index == -1 )
			{
				return null;
			}
			return formatString.substring( index + 1 );
		}
		return null;
	}
	private String getColumnName( String value )
	{