Automaton Reference

The <Automaton> element is the top-level container for a single automaton definition within an XAL file.

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Attributes

Attribute	Required	Description
Id	Yes	Unique identifier of the automaton within the file. Used by TransitionNew elements and metric queries to reference this automaton.

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Child elements

Element	Required	Description
<Functions>	Yes	Contains <Action> and <Metric> definitions. Must be present even if empty.
<States>	Yes	Contains all <State> definitions.
<InitialState>	Yes	Declares the starting state using IdState.
<Transitions>	Yes	Contains all transition elements.
<GlobalState>	No	Contains <Variable> definitions for shared state.
<Clocks>	No	Contains <Variable> definitions for clock timers.
<FinalStates>	No	Contains <FinalState> elements declaring terminal states.

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Minimal example

An automaton with two states and one transition:

<Automaton Id="SimpleMonitor">
  <Functions/>
  <GlobalState>
    <Variable Name="status" Type="string"/>
  </GlobalState>
  <Clocks/>
  <States>
    <State Id="Watching"/>
    <State Id="Alerted"/>
  </States>
  <InitialState IdState="Watching"/>
  <FinalStates>
    <FinalState IdState="Alerted"/>
  </FinalStates>
  <Transitions>
    <Transition
      IdInputState="Watching"
      IdOutputState="Alerted"
      MetricValue="critical"
      IgnoreMinWait="true"/>
  </Transitions>
</Automaton>

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Multiple automata in one file

A single XAL file commonly contains a family of related automata. The parent automaton references children by their Id in TransitionNew elements, and children reference the parent through metric queries.

<XAL>
  <Automaton Id="Parent">
    ...
    <Transitions>
      <TransitionNew
        IdInputState="Init"
        IdOutputState="Running"
        Path="myfile.xal"
        Type="Child"
        MinWait="300"/>
    </Transitions>
  </Automaton>

  <Automaton Id="Child">
    ...
  </Automaton>
</XAL>

All automaton IDs within the same file must be unique.