public override bool Equals(Object obj)
{
if (this == obj)
return true;
if ((obj == null) || (obj.GetType()!= this.GetType()))
return false;
DuplicateFilter other = (DuplicateFilter)obj;
return keepMode == other.keepMode &&
processingMode == other.processingMode &&
(fieldName == other.fieldName || (fieldName != null && fieldName.Equals(other.fieldName)));
}