VirtualNode.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Waher.Content;
using Waher.Content.Xml;
using Waher.Events;
using Waher.Networking.XMPP.DataForms;
using Waher.Networking.XMPP.DataForms.DataTypes;
using Waher.Networking.XMPP.DataForms.FieldTypes;
using Waher.Networking.XMPP.DataForms.Layout;
using Waher.Persistence;
using Waher.Runtime.Inventory;
using Waher.Runtime.Language;
using Waher.Runtime.Timing;
using Waher.Script;
using Waher.Things.ControlParameters;
using Waher.Things.DisplayableParameters;
using Waher.Things.Metering;
using Waher.Things.Metering.NodeTypes;
using Waher.Things.Virtual.Commands;
 
namespace Waher.Things.Virtual
{
    public class VirtualNode : ProvisionedMeteringNode, ICustomFormProperties, ISensor, IActuator
    {
        private static Scheduler scheduler = null;
 
        private readonly Dictionary<string, SensorData.Field> fields = new Dictionary<string, SensorData.Field>();
        private List<SensorData.Field> toReport = null;
        private DateTime nextReport = DateTime.MinValue;
        private bool hasReport = false;
 
        public VirtualNode()
            : base()
        {
        }
 
        public MetaDataValue[] MetaData { get; set; }
 
        public override Task<string> GetTypeNameAsync(Language Language)
        {
            return Language.GetStringAsync(typeof(VirtualNode), 1, "Virtual Node");
        }
 
        public override async Task<bool> AcceptsChildAsync(INode Child)
        {
            return Child is VirtualNode || await Child.AcceptsParentAsync(this);
        }
 
        public override Task<bool> AcceptsParentAsync(INode Parent)
        {
            return Task.FromResult(Parent is Root || Parent is VirtualNode);
        }
 
        public override async Task AnnotatePropertyForm(FormState Form)
        {
            await base.AnnotatePropertyForm(Form);
 
            if ((this.MetaData?.Length ?? 0) > 0)
            {
                Language Language = await Translator.GetLanguageAsync(Form.LanguageCode);
                Namespace Namespace = await Language.GetNamespaceAsync(typeof(VirtualNode).Namespace);
                string PageLabel = await Namespace.GetStringAsync(2, "Meta-data");
                string ExternalDescription = await Namespace.GetStringAsync(3, "Meta-data value is defined by external source.");
                Page MetaDataPage = new Page(Form.Form, PageLabel)
                {
                    Ordinal = Form.PageOrdinal++
                };
                Field Field;
 
                Form.Pages.Add(MetaDataPage);
                Form.PageByLabel[PageLabel] = MetaDataPage;
 
                foreach (MetaDataValue Tag in this.MetaData)
                {
                    if (Tag.Value is string s)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { s }, null, ExternalDescription, new StringDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is int i)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { i.ToString() }, null, ExternalDescription, new IntegerDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is long l)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { l.ToString() }, null, ExternalDescription, new LongDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is short sh)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { sh.ToString() }, null, ExternalDescription, new ShortDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is byte b2)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { b2.ToString() }, null, ExternalDescription, new ByteDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is double d)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { CommonTypes.Encode(d) }, null, ExternalDescription, new DoubleDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is decimal d2)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { CommonTypes.Encode(d2) }, null, ExternalDescription, new DecimalDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is bool b)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { CommonTypes.Encode(b) }, null, ExternalDescription, new BooleanDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is TimeSpan TS)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { TS.ToString() }, null, ExternalDescription, new TimeDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is DateTime TP)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { XML.Encode(TP) }, null, ExternalDescription, new DateTimeDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is Uri Uri)
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { Uri.ToString() }, null, ExternalDescription, new AnyUriDataType(),
                            null, null, false, false, false);
                    }
                    else if (Tag.Value is string[] Rows)
                    {
                        Field = new TextMultiField(Form.Form, Tag.Name, Tag.Name, false,
                            Rows, null, ExternalDescription, null, null, null, false, false, false);
                    }
                    else
                    {
                        Field = new TextSingleField(Form.Form, Tag.Name, Tag.Name, false,
                            new string[] { Tag.Value?.ToString() ?? string.Empty }, null, ExternalDescription, null,
                            null, null, false, false, false);
                    }
 
                    Field.Ordinal = Form.FieldOrdinal++;
                    Form.Fields.Add(Field);
                    MetaDataPage.Add(new FieldReference(Form.Form, Field.Var));
                }
            }
        }
 
        public bool TryGetMetaDataValue(string Name, out object Value)
        {
            if (this.metaDataByName is null)
                this.BuildDictionary();
 
            if (this.metaDataByName.TryGetValue(Name, out MetaDataValue Tag))
            {
                Value = Tag.Value;
                return true;
            }
            else
            {
                Value = null;
                return false;
            }
        }
 
        private void BuildDictionary()
        {
            SortedDictionary<string, MetaDataValue> ByName = new SortedDictionary<string, MetaDataValue>();
 
            if (!(this.MetaData is null))
            {
                foreach (MetaDataValue P in this.MetaData)
                    ByName[P.Name] = P;
            }
 
            this.metaDataByName = ByName;
        }
 
        private SortedDictionary<string, MetaDataValue> metaDataByName = null;
 
        public Task ValidateCustomProperty(Field Field)
        {
            if (this.TryGetMetaDataValue(Field.Var, out object Prev))
            {
                try
                {
                    if (Prev is string)
                        return Task.CompletedTask;
                    else if (Prev is int)
                    {
                        if (!int.TryParse(Field.ValueString, out _))
                            Field.Error = "Value must be a valid integer.";
                    }
                    else if (Prev is long)
                    {
                        if (!long.TryParse(Field.ValueString, out _))
                            Field.Error = "Value must be a valid long integer.";
                    }
                    else if (Prev is short)
                    {
                        if (!short.TryParse(Field.ValueString, out _))
                            Field.Error = "Value must be a valid short integer.";
                    }
                    else if (Prev is byte)
                    {
                        if (!byte.TryParse(Field.ValueString, out _))
                            Field.Error = "Value must be a valid byte.";
                    }
                    else if (Prev is double)
                    {
                        if (!CommonTypes.TryParse(Field.ValueString, out double _))
                            Field.Error = "Value must be a valid double-precision floating-point value.";
                    }
                    else if (Prev is decimal)
                    {
                        if (!CommonTypes.TryParse(Field.ValueString, out decimal _))
                            Field.Error = "Value must be a valid decimal-precision floating-point value.";
                    }
                    else if (Prev is bool)
                    {
                        if (!CommonTypes.TryParse(Field.ValueString, out bool _))
                            Field.Error = "Value must be a valid boolean value.";
                    }
                    else if (Prev is TimeSpan)
                    {
                        if (!TimeSpan.TryParse(Field.ValueString, out _))
                            Field.Error = "Value must be a valid TimeSpan value.";
                    }
                    else if (Prev is DateTime)
                    {
                        if (!XML.TryParse(Field.ValueString, out DateTime _))
                            Field.Error = "Value must be a valid DateTime value.";
                    }
                    else if (Prev is Uri)
                    {
                        if (!Uri.TryCreate(Field.ValueString, UriKind.Absolute, out _))
                            Field.Error = "Value must be a valid URI value.";
                    }
                    else if (Prev is string[])
                    {
                        return Task.CompletedTask;
                    }
                    else
                    {
                        return Task.CompletedTask;
                    }
                }
                catch (Exception ex)
                {
                    ex = Log.UnnestException(ex);
                    Field.Error = ex.Message;
                }
            }
 
            return Task.CompletedTask;
        }
 
        public Task SetCustomProperty(Field Field)
        {
            if (this.metaDataByName is null)
                this.BuildDictionary();
 
            if (this.metaDataByName.TryGetValue(Field.Var, out MetaDataValue Prev))
            {
                try
                {
                    if (Prev.Value is string)
                        Prev.Value = Field.ValueString;
                    else if (Prev.Value is int)
                    {
                        if (int.TryParse(Field.ValueString, out int i))
                            Prev.Value = i;
                    }
                    else if (Prev.Value is long)
                    {
                        if (long.TryParse(Field.ValueString, out long l))
                            Prev.Value = l;
                    }
                    else if (Prev.Value is short)
                    {
                        if (short.TryParse(Field.ValueString, out short sh))
                            Field.Error = "Value must be a valid short integer.";
                    }
                    else if (Prev.Value is byte)
                    {
                        if (byte.TryParse(Field.ValueString, out byte b))
                            Prev.Value = b;
                    }
                    else if (Prev.Value is double)
                    {
                        if (CommonTypes.TryParse(Field.ValueString, out double d))
                            Prev.Value = d;
                    }
                    else if (Prev.Value is decimal)
                    {
                        if (CommonTypes.TryParse(Field.ValueString, out decimal d))
                            Prev.Value = d;
                    }
                    else if (Prev.Value is bool)
                    {
                        if (CommonTypes.TryParse(Field.ValueString, out bool b))
                            Prev.Value = b;
                    }
                    else if (Prev.Value is TimeSpan)
                    {
                        if (TimeSpan.TryParse(Field.ValueString, out TimeSpan TS))
                            Prev.Value = TS;
                    }
                    else if (Prev.Value is DateTime)
                    {
                        if (XML.TryParse(Field.ValueString, out DateTime TP))
                            Prev.Value = TP;
                    }
                    else if (Prev.Value is Uri)
                    {
                        if (Uri.TryCreate(Field.ValueString, UriKind.Absolute, out Uri Url))
                            Prev.Value = Url;
                    }
                    else if (Prev.Value is string[])
                        Prev.Value = Field.ValueStrings;
                    else
                        Prev.Value = Field.ValueString;
                }
                catch (Exception ex)
                {
                    ex = Log.UnnestException(ex);
                    Field.Error = ex.Message;
                }
            }
            else
                this.SetMetaDataPriv(Field.Var, Field.ValueString);
 
            return Task.CompletedTask;
        }
 
        public object GetMetaData(string Name)
        {
            if (this.TryGetMetaDataValue(Name, out object Value))
                return Value;
            else
                return null;
        }
 
        public async Task SetMetaData(string Name, object Value)
        {
            if (this.metaDataByName is null)
                this.BuildDictionary();
 
            if (this.metaDataByName.TryGetValue(Name, out MetaDataValue Tag))
                Tag.Value = Value;
            else
                this.SetMetaDataPriv(Name, Value);
 
            await Database.Update(this);
        }
 
        private void SetMetaDataPriv(string Name, object Value)
        {
            this.metaDataByName[Name] = new MetaDataValue()
            {
                Name = Name,
                Value = Value
            };
 
            MetaDataValue[] Values = new MetaDataValue[this.metaDataByName.Count];
            this.metaDataByName.Values.CopyTo(Values, 0);
            this.MetaData = Values;
        }
 
        public override async Task<IEnumerable<Parameter>> GetDisplayableParametersAsync(Language Language, RequestOrigin Caller)
        {
            LinkedList<Parameter> Result = await base.GetDisplayableParametersAsync(Language, Caller) as LinkedList<Parameter>;
 
            if (!(this.MetaData is null))
            {
                foreach (MetaDataValue Tag in this.MetaData)
                {
                    if (Tag.Value is string s)
                        Result.AddLast(new StringParameter(Tag.Name, Tag.Name, s));
                    else if (Tag.Value is int i)
                        Result.AddLast(new Int32Parameter(Tag.Name, Tag.Name, i));
                    else if (Tag.Value is long l)
                        Result.AddLast(new Int64Parameter(Tag.Name, Tag.Name, l));
                    else if (Tag.Value is short sh)
                        Result.AddLast(new Int32Parameter(Tag.Name, Tag.Name, sh));
                    else if (Tag.Value is byte b)
                        Result.AddLast(new Int32Parameter(Tag.Name, Tag.Name, b));
                    else if (Tag.Value is double d)
                        Result.AddLast(new DoubleParameter(Tag.Name, Tag.Name, d));
                    else if (Tag.Value is decimal d2)
                        Result.AddLast(new DoubleParameter(Tag.Name, Tag.Name, (double)d2));
                    else if (Tag.Value is bool b2)
                        Result.AddLast(new BooleanParameter(Tag.Name, Tag.Name, b2));
                    else if (Tag.Value is TimeSpan TS)
                        Result.AddLast(new TimeSpanParameter(Tag.Name, Tag.Name, TS));
                    else if (Tag.Value is DateTime TP)
                        Result.AddLast(new DateTimeParameter(Tag.Name, Tag.Name, TP));
                    else if (Tag.Value is Uri Uri)
                        Result.AddLast(new StringParameter(Tag.Name, Tag.Name, Uri.ToString()));
                }
            }
 
            return Result;
        }
 
        public void ReportSensorData(SensorData.Field Field)
        {
            this.ReportSensorData(new SensorData.Field[] { Field });
        }
 
        public void ReportSensorData(params SensorData.Field[] Fields)
        {
            if (scheduler is null && Types.TryGetModuleParameter("Scheduler", out object Obj) && Obj is Scheduler Scheduler)
                scheduler = Scheduler;
 
            lock (this.fields)
            {
                foreach (SensorData.Field Field in Fields)
                {
                    this.fields[Field.Name] = Field;
 
                    if (Field.Type.HasFlag(SensorData.FieldType.Momentary))
                    {
                        if (this.toReport is null)
                            this.toReport = new List<SensorData.Field>();
 
                        this.toReport.Add(Field);
                        this.hasReport = true;
                    }
                }
 
                if (this.hasReport)
                {
                    if (scheduler is null)
                    {
                        this.NewMomentaryValues(this.toReport.ToArray());
                        this.toReport.Clear();
                        this.hasReport = false;
                    }
                    else
                    {
                        if (this.nextReport != DateTime.MinValue)
                            scheduler.Remove(this.nextReport);
 
                        this.nextReport = scheduler.Add(DateTime.Now.AddMilliseconds(250), this.DoReport, null);
                    }
                }
            }
        }
 
        private void DoReport(object _)
        {
            lock (this.fields)
            {
                this.NewMomentaryValues(this.toReport.ToArray());
                this.toReport.Clear();
                this.hasReport = false;
            }
        }
 
        public Task StartReadout(ISensorReadout Request)
        {
            return this.StartReadout(Request, true);
        }
 
        public override bool IsReadable
        {
            get
            {
                lock (this.fields)
                {
                    return this.fields.Count > 0;
                }
            }
        }
 
        public virtual Task StartReadout(ISensorReadout Request, bool DoneAfter)
        {
            List<SensorData.Field> ToReport = new List<SensorData.Field>();
 
            lock (this.fields)
            {
                foreach (SensorData.Field Field in this.fields.Values)
                {
                    if (Request.IsIncluded(Field.Name, Field.Timestamp, Field.Type))
                        ToReport.Add(Field);
                }
            }
 
            if (DoneAfter || ToReport.Count > 0)
                Request.ReportFields(DoneAfter, ToReport.ToArray());
 
            return Task.CompletedTask;
        }
 
        public override bool IsControllable 
        {
            get
            {
                if (this.TryGetMetaDataValue("Callback", out object Obj) && Obj is string &&
                    this.TryGetMetaDataValue("Payload", out Obj) && Obj is string &&
                    this.TryGetMetaDataValue("FieldName", out Obj) && Obj is string &&
                    this.TryGetMetaDataValue("FieldValue", out object FieldValue))
                {
                    return
                        FieldValue is double ||
                        FieldValue is string ||
                        FieldValue is bool ||
                        FieldValue is Enum ||
                        FieldValue is DateTime ||
                        FieldValue is TimeSpan ||
                        FieldValue is Duration ||
                        FieldValue is sbyte ||
                        FieldValue is short ||
                        FieldValue is int ||
                        FieldValue is long ||
                        FieldValue is byte ||
                        FieldValue is ushort ||
                        FieldValue is uint ||
                        FieldValue is ulong;
                }
                else
                    return false;
            }
        }
 
        public virtual Task<ControlParameter[]> GetControlParameters()
        {
            List<ControlParameter> Parameters = new List<ControlParameter>();
 
            if (this.TryGetMetaDataValue("Callback", out object Obj) && Obj is string CallbackUrl &&
                this.TryGetMetaDataValue("Payload", out Obj) && Obj is string PayloadScript &&
                this.TryGetMetaDataValue("FieldName", out Obj) && Obj is string FieldName &&
                this.TryGetMetaDataValue("FieldValue", out object FieldValue))
            {
                if (FieldValue is double d)
                {
                    Parameters.Add(new DoubleControlParameter(FieldName, "Control", FieldName + ":", "Value to set.",
                        _ => Task.FromResult<double?>(d),
                        async (_, Value) =>
                        {
                            d = Value;
                            await this.DoCallback(CallbackUrl, PayloadScript, d);
                        }));
                }
                else if (FieldValue is string s)
                {
                    Parameters.Add(new StringControlParameter(FieldName, "Control", FieldName + ":", "Value to set.",
                        _ => Task.FromResult<string>(s),
                        async (_, Value) =>
                        {
                            s = Value;
                            await this.DoCallback(CallbackUrl, PayloadScript, s);
                        }));
                }
                else if (FieldValue is bool b)
                {
                    Parameters.Add(new BooleanControlParameter(FieldName, "Control", FieldName + ":", "Value to set.",
                        _ => Task.FromResult<bool?>(b),
                        async (_, Value) =>
                        {
                            b = Value;
                            await this.DoCallback(CallbackUrl, PayloadScript, b);
                        }));
                }
                else if (FieldValue is Enum e)
                {
                    Parameters.Add(new EnumControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", e.GetType(),
                        _ => Task.FromResult<Enum>(e),
                        async (_, Value) =>
                        {
                            e = Value;
                            await this.DoCallback(CallbackUrl, PayloadScript, e);
                        }));
                }
                else if (FieldValue is DateTime DT)
                {
                    Parameters.Add(new DateTimeControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", null, null,
                        _ => Task.FromResult<DateTime?>(DT),
                        async (_, Value) =>
                        {
                            DT = Value;
                            await this.DoCallback(CallbackUrl, PayloadScript, DT);
                        }));
                }
                else if (FieldValue is TimeSpan TS)
                {
                    Parameters.Add(new TimeControlParameter(FieldName, "Control", FieldName + ":", "Value to set.",
                        _ => Task.FromResult<TimeSpan?>(TS),
                        async (_, Value) =>
                        {
                            TS = Value;
                            await this.DoCallback(CallbackUrl, PayloadScript, TS);
                        }));
                }
                else if (FieldValue is Duration D)
                {
                    Parameters.Add(new DurationControlParameter(FieldName, "Control", FieldName + ":", "Value to set.",
                        _ => Task.FromResult<Duration>(D),
                        async (_, Value) =>
                        {
                            D = Value;
                            await this.DoCallback(CallbackUrl, PayloadScript, D);
                        }));
                }
                else if (FieldValue is sbyte i8)
                {
                    Parameters.Add(new Int32ControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", sbyte.MinValue, sbyte.MaxValue,
                        _ => Task.FromResult<int?>(i8),
                        async (_, Value) =>
                        {
                            i8 = (sbyte)Value;
                            await this.DoCallback<int>(CallbackUrl, PayloadScript, i8);
                        }));
                }
                else if (FieldValue is short i16)
                {
                    Parameters.Add(new Int32ControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", short.MinValue, short.MaxValue,
                        _ => Task.FromResult<int?>(i16),
                        async (_, Value) =>
                        {
                            i16 = (short)Value;
                            await this.DoCallback<int>(CallbackUrl, PayloadScript, i16);
                        }));
                }
                else if (FieldValue is int i32)
                {
                    Parameters.Add(new Int32ControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", null, null,
                        _ => Task.FromResult<int?>(i32),
                        async (_, Value) =>
                        {
                            i32 = Value;
                            await this.DoCallback<int>(CallbackUrl, PayloadScript, i32);
                        }));
                }
                else if (FieldValue is long i64)
                {
                    Parameters.Add(new Int64ControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", null, null,
                        _ => Task.FromResult<long?>(i64),
                        async (_, Value) =>
                        {
                            i64 = Value;
                            await this.DoCallback<long>(CallbackUrl, PayloadScript, i64);
                        }));
                }
                else if (FieldValue is byte ui8)
                {
                    Parameters.Add(new Int32ControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", byte.MinValue, byte.MaxValue,
                        _ => Task.FromResult<int?>(ui8),
                        async (_, Value) =>
                        {
                            ui8 = (byte)Value;
                            await this.DoCallback<int>(CallbackUrl, PayloadScript, ui8);
                        }));
                }
                else if (FieldValue is ushort ui16)
                {
                    Parameters.Add(new Int32ControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", ushort.MinValue, ushort.MaxValue,
                        _ => Task.FromResult<int?>(ui16),
                        async (_, Value) =>
                        {
                            ui16 = (ushort)Value;
                            await this.DoCallback<int>(CallbackUrl, PayloadScript, ui16);
                        }));
                }
                else if (FieldValue is uint ui32)
                {
                    Parameters.Add(new Int64ControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", uint.MinValue, uint.MaxValue,
                        _ => Task.FromResult<long?>(ui32),
                        async (_, Value) =>
                        {
                            ui32 = (uint)Value;
                            await this.DoCallback<long>(CallbackUrl, PayloadScript, ui32);
                        }));
                }
                else if (FieldValue is ulong ui64)
                {
                    Parameters.Add(new DoubleControlParameter(FieldName, "Control", FieldName + ":", "Value to set.", ulong.MinValue, ulong.MaxValue,
                        _ => Task.FromResult<double?>(ui64),
                        async (_, Value) =>
                        {
                            ui64 = (ulong)Value;
                            await this.DoCallback<double>(CallbackUrl, PayloadScript, ui64);
                        }));
                }
            }
 
            return Task.FromResult(Parameters.ToArray());
        }
 
        private async Task DoCallback<T>(string CallbackUrl, string PayloadScript, T Value)
        {
            Variables v = new Variables
            {
                { "Value", Value }
            };
 
            object Payload = await Expression.EvalAsync(PayloadScript, v);
            await InternetContent.PostAsync(new Uri(CallbackUrl), Payload);
        }
 
        public override Task<IEnumerable<ICommand>> Commands => this.GetCommands();
 
        private async Task<IEnumerable<ICommand>> GetCommands()
        {
            List<ICommand> Commands = new List<ICommand>();
            Commands.AddRange(await base.Commands);
 
            Commands.Add(new AddMetaDataString(this));
            Commands.Add(new AddMetaDataInt32(this));
            Commands.Add(new AddMetaDataInt64(this));
            Commands.Add(new AddMetaDataDouble(this));
            Commands.Add(new AddMetaDataBoolean(this));
            Commands.Add(new AddMetaDataDateTime(this));
            Commands.Add(new AddMetaDataTimeSpan(this));
            Commands.Add(new AddMetaDataDuration(this));
 
            return Commands.ToArray();
        }
 
    }
}