Camunda Modeler Decision Table : Can we source the predefined values (InputValues) for a string input from an external endpoint? - camunda

Question

I have an api endpoint which returns a set of values. I want to use these values as a source for predefined values for the input fields in the decision table.
As of now, I can only see the possibility of adding these values as static values in the Modeler. Checked the camunda documentation, could not find anything relevant to this requirement.
Any pointers would be helpful.

Answer 1

You have a few different options to pull values from an external source for use in a decision table. For the purposes of this response, I'll assume your external source is a REST API endpoint. Here are those options:
You could call the decision table from a process definition, and you could source the external values in the process definition prior to the call to the decision table. For example, you could use a Service Task configured as an 'http-connector' to pull the values.
You could expand your decision table such that it becomes a DRD (Decision Requirements Diagram) and utilize a Decision Literal Expression to pull that data.
Finally, you could embed your code to pull data from the external source within a Java bean that is known to the process engine in the current context and call that bean from within your decision table.
I know there's a lot there; if any of it sounds foreign, please review the Camunda documentation at https://docs.camunda.org.
Let me focus on #2 above for a moment and give you a specific example... If you chose that route, your Decision Literal Expression could have the following code within it:
//Get access to the Connectors and Spin Objects.
var Connectors = Java.type('org.camunda.connect.Connectors');
var Spin = Java.type('org.camunda.spin.Spin');
//Create an instance of the HTTP Connector and make the request.
var httpConnector = Connectors.http();
var resp = httpConnector.createRequest()
.post()
.url('http://localhost:1027/creditscore')
.contentType('application/json')
.payload('{"ssn":\"' + ssn + '\"}')
.execute()
.getResponse();
//Retrieve the credit score from the response.
var creditScore = Spin.JSON(resp).prop('creditScore').numberValue();
//Return the credit score, setting it to the variable name specified here.
creditScore;
In that example, I've set the variable name to "creditScore", the type of the variable to "long" and the expression language to "javascript". It requires one variable as input, with that being "ssn". You would be able to use that variable "creditScore" in any decision tables that depend on that decision literal expression in your DRD.