SensorThingsClient

This library provides a Java-based client library for the SensorThingsAPI and aims to simplify development of SensorThings enabled client applications.

Note: This project is still under development and therefore lacks complete support of the SensorThingsAPI.

Features

• CRUD operations
• Queries on entity sets
• Loading of referenced entities

Unsupported

• Batch requests
• $select
• MultiDatastream
• dataArray
• MQTT

API

The SensorThingsService class is central to the library. An instance of it represents a SensorThings service and is identified by an URI.

CRUD operations

The source code below demonstrates the CRUD operations for Thing objects. Operations for other entities work similarly.

URI serviceEndpoint = URI.create("http://example.org/v1.0/");
SensorThingsService service = new SensorThingsService(serviceEndpoint);

Thing thing = new Thing();
thing.setDescription("I'm a thing!");
service.things().create(thing);

thing = service.things().find(1l);

thing.setDescription("Things change...");
service.things().update(thing);

service.things().delete(thing);

Entity Sets

Entity Sets are represented by instances of EntityList<>. The query parameters specified by the SensorThingsAPI standard can be applied to queries.

EntityList<Thing> things = service.things()
							.query()
							.count()
							.orderBy("description")
							.filter("")
							.skip(5)
							.top(10)
							.list();

for (Thing thing : things) {
	System.out.println("So many things!");
}

However, $expand does not work on queries yet.

Loading referenced objects

Loading referenced objects in one operation (and therefore in one request) is supported. The $expand option of the SensorThingsAPI standard is used internally.

Thing thing = service.things().find(1l,
				Expansion.of(EntityType.THING)
				.with(ExpandedEntity.from(EntityType.LOCATIONS)));
EntityList<Location> locations = thing.getLocations();

Background

This library emerged from a practical work for a lecture at KIT in collaboration with the Fraunhofer IOSB. A server implementation of the SensorThingsAPI, developed by the Fraunhofer IOSB, is available on GitHub as well.

Contributing

Contributions are welcome!

1. Fork this repository
2. Commit your changes
3. Create a pull request

License

The code and the documentation of this work is available under the MIT license.