dynamic multicast?

[edmundchong]

Hi, I was wondering if it is possible to dynamically change the subject of MulticastSubject during the workflow execution? It has the Name property which can be externalized--can this be set and changed on the fly?

[bruno-f-cruz]

Edit: the following solution wont work. Sorry for the misleading information!

If you manage to defer their creation (e.g. inside a SelectMany) then yes.
E.g.:

Click me - Copy&Paste

<?xml version="1.0" encoding="utf-8"?>
<WorkflowBuilder Version="2.7.1"
               xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
               xmlns:rx="clr-namespace:Bonsai.Reactive;assembly=Bonsai.Core"
               xmlns:sys="clr-namespace:System;assembly=mscorlib"
               xmlns="https://bonsai-rx.org/2018/workflow">
<Workflow>
  <Nodes>
    <Expression xsi:type="rx:BehaviorSubject" TypeArguments="sys:Int32">
      <rx:Name>A</rx:Name>
    </Expression>
    <Expression xsi:type="rx:BehaviorSubject" TypeArguments="sys:Int32">
      <rx:Name>B</rx:Name>
    </Expression>
    <Expression xsi:type="Combinator">
      <Combinator xsi:type="rx:Timer">
        <rx:DueTime>PT5S</rx:DueTime>
        <rx:Period>PT0S</rx:Period>
      </Combinator>
    </Expression>
    <Expression xsi:type="Combinator">
      <Combinator xsi:type="StringProperty">
        <Value>A</Value>
      </Combinator>
    </Expression>
    <Expression xsi:type="rx:SelectMany">
      <Workflow>
        <Nodes>
          <Expression xsi:type="WorkflowInput">
            <Name>Source1</Name>
          </Expression>
          <Expression xsi:type="PropertyMapping">
            <PropertyMappings>
              <Property Name="Name" />
            </PropertyMappings>
          </Expression>
          <Expression xsi:type="Combinator">
            <Combinator xsi:type="IntProperty">
              <Value>0</Value>
            </Combinator>
          </Expression>
          <Expression xsi:type="MulticastSubject">
            <Name>A</Name>
          </Expression>
        </Nodes>
        <Edges>
          <Edge From="0" To="1" Label="Source1" />
          <Edge From="1" To="3" Label="Source2" />
          <Edge From="2" To="3" Label="Source1" />
        </Edges>
      </Workflow>
    </Expression>
    <Expression xsi:type="Combinator">
      <Combinator xsi:type="StringProperty">
        <Value>B</Value>
      </Combinator>
    </Expression>
    <Expression xsi:type="rx:SelectMany">
      <Workflow>
        <Nodes>
          <Expression xsi:type="WorkflowInput">
            <Name>Source1</Name>
          </Expression>
          <Expression xsi:type="PropertyMapping">
            <PropertyMappings>
              <Property Name="Name" />
            </PropertyMappings>
          </Expression>
          <Expression xsi:type="Combinator">
            <Combinator xsi:type="IntProperty">
              <Value>0</Value>
            </Combinator>
          </Expression>
          <Expression xsi:type="MulticastSubject">
            <Name>B</Name>
          </Expression>
        </Nodes>
        <Edges>
          <Edge From="0" To="1" Label="Source1" />
          <Edge From="1" To="3" Label="Source2" />
          <Edge From="2" To="3" Label="Source1" />
        </Edges>
      </Workflow>
    </Expression>
    <Expression xsi:type="SubscribeSubject">
      <Name>A</Name>
    </Expression>
    <Expression xsi:type="SubscribeSubject">
      <Name>B</Name>
    </Expression>
  </Nodes>
  <Edges>
    <Edge From="2" To="3" Label="Source1" />
    <Edge From="2" To="5" Label="Source1" />
    <Edge From="3" To="4" Label="Source1" />
    <Edge From="5" To="6" Label="Source1" />
  </Edges>
</Workflow>
</WorkflowBuilder>

[edmundchong]

Hi Bruno,

I couldn't quite get this to work:

In my code I try to set it up so that the key i press will determine which subject i multicast to, but it doesn't seem to do anything:

multicaster.bonsai.txt

[bruno-f-cruz]

Uhm I guess I was wrong. I thought if the type was compatible it would be possible but I guess not.

An alternative solution would be to use a filter prior to the subject to pipe the message to the desired subject. For instance using Tuple<int, data> where the int would be used in a condition to decide what subject to use.

[edmundchong]

I guess you mean something like this (Source1 is the output of CsvReader)?

Thanks!

[bruno-f-cruz]

Looks like it, yes!

[edmundchong]

answer: see above in replies (and thanks bruno for the discussion)