Transitions Reference

Transitions define how the automaton moves between states. Four transition types are available, each with its own element name and set of attributes.

Common attributes

All transition types share these attributes:

Attribute	Required	Description
`IdInputState`	Yes	ID of the state the automaton must be in for the transition to fire
`IdOutputState`	Yes	ID of the state the automaton moves to when the transition fires
`IgnoreMinWait`	No	If `true`, bypasses the minimum wait interval between successive firings

Transition

The standard transition. Fires when a metric value matches and/or clock constraints are satisfied.

<Transition
  IdInputState="Waiting"
  IdOutputState="Processing"
  MetricValue="confirmed"
  IgnoreMinWait="true">
  <ClockConstraint ClockExp="clk_wait &lt; T_max_wait"/>
  <ClockReset ClockVar="clk_wait"/>
</Transition>

Additional attributes:

Attribute	Description
`MetricValue`	The metric return value that triggers the transition

Child elements:

Element	Description
`<ClockConstraint ClockExp="..."/>`	A time-based condition. Multiple elements allowed.
`<ClockReset ClockVar="..."/>`	Resets the specified clock when the transition fires. Multiple elements allowed.

TransitionNew

Spawns a child automaton and moves to the output state. Used to build automaton families.

<TransitionNew
  IdInputState="Init"
  IdOutputState="Processing"
  Path="ecommerce_backoffice.xal"
  Type="Operator"
  MinWait="300"
  IgnoreMinWait="true">
  <Input>
    <Parameter LocalVariable="shopifyApiEndpoint" TargetVariable="shopifyApiEndpoint"/>
    <Parameter LocalVariable="orderId" TargetVariable="orderId"/>
  </Input>
</TransitionNew>

Additional attributes:

Attribute	Required	Description
`Path`	Yes	File name of the XAL file containing the target automaton
`Type`	Yes	ID of the automaton to instantiate
`MinWait`	No	Minimum delay in seconds before the child begins processing

Child elements:

Element	Description
`<Input><Parameter .../></Input>`	Maps parent global state variables to child global state variables
`<ClockConstraint>`, `<ClockReset>`	Same as `Transition`

TransitionNewMulti

Like TransitionNew, but iterates over a list variable and spawns one child instance per item.

<TransitionNewMulti
  IdInputState="Init"
  IdOutputState="Running"
  Path="patcher.xal"
  Type="RecycleAppPools"
  MinWait="300">
  <LoopInput>
    <Parameter LocalVariable="AppPools" TargetVariable="AppPool"/>
  </LoopInput>
  <Input>
    <Parameter LocalVariable="erpOrderId" TargetVariable="orderId"/>
  </Input>
</TransitionNewMulti>

Additional child elements:

Element	Description
`<LoopInput><Parameter .../></LoopInput>`	A single list variable from the parent's global state. One child is spawned per item.

TransitionX

An extended transition that combines features of Transition and TransitionNew. It supports both a MetricValue condition and the ability to spawn a child automaton through a <New> child element.

<TransitionX
  IdInputState="Active"
  IdOutputState="Handling"
  MetricValue="alert">
  <New Path="handlers.xal" Type="AlertHandler" MinWait="300"/>
  <ClockReset ClockVar="clk_alert"/>
</TransitionX>