SubscribeTo.cs

using System;
using System.Collections.Generic;
using System.Xml;
using System.Threading.Tasks;
using TAG.Simulator.ObjectModel;
using TAG.Simulator.ObjectModel.Activities;
using TAG.Simulator.XMPP.Actors;
using Waher.Content.Xml;
using Waher.Script;
using System.IO;
 
namespace TAG.Simulator.XMPP.Activities
{
    public class SubscribeTo : ActivityNode
    {
        private StringAttribute actor;
        private StringAttribute to;
 
        public SubscribeTo(ISimulationNode Parent, Model Model)
            : base(Parent, Model)
        {
        }
 
        public override string LocalName => nameof(SubscribeTo);
 
        public override string SchemaResource => XmppActor.XmppSchema;
 
        public override string Namespace => XmppActor.XmppNamespace;
 
        public override ISimulationNode Create(ISimulationNode Parent, Model Model)
        {
            return new SubscribeTo(Parent, Model);
        }
 
        public override Task FromXml(XmlElement Definition)
        {
            this.actor = new StringAttribute(XML.Attribute(Definition, "actor"));
            this.to = new StringAttribute(XML.Attribute(Definition, "to"));
 
            return base.FromXml(Definition);
        }
 
        public override async Task<LinkedListNode<IActivityNode>> Execute(Variables Variables)
        {
            string To = await this.to.GetValueAsync(Variables);
 
            object Obj = await this.GetActorObjectAsync(this.actor, Variables);
            if (!(Obj is XmppActivityObject XmppActor))
                throw new Exception("Actor not an XMPP client.");
 
            await XmppActor.Client.RequestPresenceSubscription(To);
 
            return null;
        }
 
        public override void ExportPlantUml(StreamWriter Output, int Indentation, char QuoteChar)
        {
            base.ExportPlantUml(Output, Indentation, QuoteChar);
 
            Indent(Output, Indentation);
            Output.Write(':');
            Output.Write(this.actor.Value);
            Output.Write(".SubscribeTo");
            Output.Write("(");
 
            Indentation++;
 
            SendMessage.AppendArgument(Output, Indentation, "To", this.to.Value, true, QuoteChar);
            
            Output.WriteLine(");");
        }
 
    }
}