Example: DMN FEEL 1.2 for Camunda BPM Platform

Let's have a look at the following example to get a better understanding of how FEEL 1.2 integrates with Camunda BPM.

In this example, we want to calculate the maximum credit sum that we can grant to a customer based on the requested type of the credit and the credit score.

When the credit score of a customer is…

• ... weaker than 80% of the average credit score:
  no credit is granted

• ... between 80% and 100% of the average credit score:
  the historical average credit sum is granted

• ... better than the average credit score:
  1.5 times of the historical average credit sum is granted

Based on the business context explained above, I created a DMN Decison Table & Literal Expression which uses FEEL 1.2 Expressions exclusively.

Step-By-Step Guide

To try out the example yourself, follow the step-by-step guide below.

Step 1: Run Camunda BPM

Run the following command in your terminal:

mvn clean install && java -jar ./target/feel-example-1.0.0-SNAPSHOT.jar

Step 2: Evaluate Decision

Evaluate the decision by performing the following REST API request:

POST /decision-definition/key/calc-credit-sum/evaluate

{
   "variables":{
      "credit_history":{
         "value":" [{\"type\":\"personal-loan\", \"score\": 505, \"granted_sum\": 1554.30}, {\"type\":\"mortgage\", \"score\": 931, \"granted_sum\": 600900.43}, {\"type\":\"mortgage\", \"score\": 754, \"granted_sum\": 210000.00}, {\"type\":\"personal-loan\", \"score\": 437, \"granted_sum\": 1900.44}]",
         "type": "Json"
      },
      "credit_score":{
         "value": 800
      },
      "credit_type":{
         "value": "mortgage"
      }
   }
}

Step 3: Review Decision History

Go to Cockpit and open the decision instance view to see the result: