Introducing Feature Definition

Brace yourselves, Eclipse Vorto is going to be integrated with Ditto.

Rationale

By now you most probably represented your devices as things with features. This is indeed the proper way to do it. This approach is flexible and easy so far.

But wouldn’t it be nice to have the possibility of providing an explicit schema for the digital twins of your devices?

This is where Eclipse Vorto enters the game. Vorto enables you to define information models and function blocks which would be mapped to things and features in Ditto.

To make a feature aware of a schema we have extended feature by a definition. A feature definition is a means of describing the type of a feature, thus enabling the validation the integrity of a feature’s properties.

Technically, a definition is an array of identifier strings each of which having the form <namespace>:<name>:<version>.

A fully-fledged JSON representation of a feature with a definition is shown below:

{
    "lamp": {
        "definition": [ "com.mycompany.fb:Lamp:1.0.0" ],
        "properties": {
            "configuration": {
                "on": true,
                "location": {
                    "longitude": 34.052235,
                    "latitude": -118.243683
                }
            },
            "status": {
                "on": false,
                "color": {
                    "red": 128,
                    "green": 255,
                    "blue": 0
                }
            }
        }
    }
}

For diving deeper into feature definitions, please have a look at Basic concept - Feature Definition.

Validation

However, nothing can stop you from enforcing types by yourself:

1. Use the Ditto generator to generate JSON schema files from your Vorto model(s).
2. Identify the schema files to be used by the Feature definition identifiers.
3. Validate the JSON representation of your feature using the JSON schema before sending it over the wire.

Example

Please find more information and an example at Basic concept - Feature Definition.

–
The Eclipse Ditto team