CORAL WIKI
Actors
Getting started
Overview
FsmActor
The FsmActor (finite state machine actor) is a Coral Actor that keeps state that can be changed due to trigger events.
Creating a FsmActor
The creation JSON of the FSM actor (see Coral Actor) has "type": "fsm".
The params value is a JSON with the following fields:
| field | type | required | description |
|---|---|---|---|
key |
string | yes | the name of the field in the trigger-JSON that can affect the state |
table |
map | yes | a map of maps of state transitions |
s0 |
string | yes | the initial state |
Example
{
"data": {
"type": "actors",
"attributes": {
"type": "fsm",
"params": {
"key": "transactionsize",
"table": {
"normal": {
"small": "normal",
"large": "normal",
"x-large": "suspicious"
},
"suspicious": {
"small": "normal",
"large": "suspicious",
"x-large": "alarm"
},
"alarm":{
"small": "suspicious",
"large": "alarm",
"x-large": "alarm"
}
},
"s0": "normal"
}
}
}
}Note that the initial state s0 must be a valid key in the table.
Trigger
The FsmActor only does useful work if the trigger is connected.
The actor checks for the key field and changes state if appropriate.
Example
Taking the example constructor above, the initial state is normal. Now if a trigger JSON contains "transactionsize": "x-large" then the state will change to suspicious.
Another trigger with the same "transactionsize": "x-large" will now change to state to alarm.
Emit
The FsmActor emits nothing. Only the state provides information.
State
The FsmActor keeps the FSM state in a map as coral actor state:
| field | type | description |
|---|---|---|
s |
string | the (FSM) state label |
The state is updated according to the table due to trigger events.
Collect
The FsmActor does not collect state from other actors.
Timer
The FsmActor does not provide timer actions.