Google.GData.Extensions.When.CreateInstance C# (CSharp) Method

        public IExtensionElementFactory CreateInstance(XmlNode node, AtomFeedParser parser)
        {
            Tracing.TraceCall();
            When when = null;

            if (node != null)
            {
                object localname = node.LocalName;
                if (!localname.Equals(this.XmlName) ||
                    !node.NamespaceURI.Equals(this.XmlNameSpace))
                {
                    return null;
                }
            }

            bool startTimeFlag = false, endTimeFlag = false;

            when = new When();
            if (node != null)
            {
                if (node.Attributes != null)
                {
                    String value = node.Attributes[GDataParserNameTable.XmlAttributeStartTime] != null ? 
                        node.Attributes[GDataParserNameTable.XmlAttributeStartTime].Value : null; 
                    if (value != null)
                    {
                        startTimeFlag = true;
                        when.startTime = DateTime.Parse(value);
                        when.AllDay = (value.IndexOf('T') == -1); 
                    }
                
                    value = node.Attributes[GDataParserNameTable.XmlAttributeEndTime] != null ? 
                        node.Attributes[GDataParserNameTable.XmlAttributeEndTime].Value : null; 
                
                    if (value != null)
                    {
                        endTimeFlag = true;
                        when.endTime = DateTime.Parse(value); 
                        when.AllDay = when.AllDay && (value.IndexOf('T') == -1); 
                    }
                
                    if (node.Attributes[GDataParserNameTable.XmlAttributeValueString] != null)
                    {
                        when.valueString = node.Attributes[GDataParserNameTable.XmlAttributeValueString].Value;
                    }
                }
                // single event, g:reminder is inside g:when
                if (node.HasChildNodes)
                {
                    XmlNode whenChildNode = node.FirstChild;
                    IExtensionElementFactory f = new Reminder() as IExtensionElementFactory;
                    while (whenChildNode != null && whenChildNode is XmlElement)
                    {
                        if (String.Compare(whenChildNode.NamespaceURI, f.XmlNameSpace, true, CultureInfo.InvariantCulture) == 0)
                        {
                            if (String.Compare(whenChildNode.LocalName, f.XmlName, true, CultureInfo.InvariantCulture) == 0)
                            {
                                Reminder r = f.CreateInstance(whenChildNode, null) as Reminder;
                                when.Reminders.Add(r);
                            }
                        }
                        whenChildNode = whenChildNode.NextSibling;
                    }
                }
            }
            
            if (!startTimeFlag)
            {
                throw new ClientFeedException("g:when/@startTime is required.");
            }

            if (endTimeFlag && when.startTime.CompareTo(when.endTime) > 0)
            {
                throw new ClientFeedException("g:when/@startTime must be less than or equal to g:when/@endTime.");
            }

            return when;
        }