Persistence

The Extension API includes high-level abstractions for many things. Among them are persistence services.

To save arbitrary data for later use (stateful Nodes), you can use the NodePersistenceService. Its rudimentary API allows you to add, get and remove a number of entities by their ID. Under the hood, your data is serialized using Kotlinx.serialization and persisted in a Key-Value data store.

For Database Adapter developers

The simple interface shouldn't be too much of a challenge to implement, as long as you can persist JSON using a composite of the Node ID and the Entity ID as the key.