How to connect a JSON file to a Decision Model and Notation (DMN) model

Connecting a JSON file to a DMN project is a simple task in the FlexRule platform. The data can be mapped out and manipulated in however your project requires. A JSON file can be accessed in FlexRule to create a JSON object.

Add an Activity Flow to your DMN Project

Add an Activity Flow by selecting the Add New Document icon in the project explorer, and you can find it under Business Logic. Or if you already have an activity flow where it makes sense to add the file node, you can add it there.

In the activity flow, add a start and end node (every activity flow requires one). Open the toolbox with Alt+x

Add a JSON file to a DMN Project

Scroll down in the toolbox to the Data section and add a file node to the flow.

Select the node and in the properties window to the left and fill in informaiton for Type, CopyValueTo, and URI.

Set the Type to JSON.

Enter the file location into the URI field, and the data will be copied into the parameter entered into the CopyValueTo field. The result will be a JSON parameter.

A JSON File as an Input

Using the Age Classification sample project as an example, we can take in a JSON file as input to the DRD. To do this create a flow, add a file node, and drag and drop the DRD into the flow. Create a parameter to store the JSON file. Here is an example JSON file you could use with the Age Categorization project:

{
    "Age":30
}

Fill in the correct settings in the parameters window:

View the values of the JSON object in the parameter window.

Add a Spread Sheet to a DRD

Alternatively, drag and drop the flow into the DRD orchestraing the DMN project so the flow becomes one of the decision nodes of the main orchestration.

Summary

Connect to JSON file types in DMN projects using the File node of an Activity Flow logic document. If your main orchestration for a DMN project is a DRD, you can create an Activity Flow with a File node and then drag and drop it into your DRD. Debug the project (or run it) to view the JSON file values in the parameter window and data viewer.