Simple TTN client for JavaEE

This is a simple client library to connect to the things network and receive messages inside a JavaEE application container. It provides an context listener that will be initialized (should be discovered by a container like Apache Tomcat by it's annotation) based on the context configuration (either from your servers context.xml or the local WebContent/WEB-INF/web.xml.

The configuration is pretty simple. There are three basic configuration parameters. The first context parameter is ttnconnections. It contains a comma separated list of names of connections that should be automatically established on context initialization (i.e. most of the time this is equivalent to the deployment of the application container).

`<context-param>
	<param-name>ttnconnections</param-name>
	<param-value>con1</param-value>
</context-param>

For every named connection there is an url and handler parameter. The URL parameter contains protocol, application ID and authentication information as well as the region that the client should connect to. To connect to an application in the EU region the URI would look like the following:

<context-param>
	<param-name>con1-url</param-name>
	<param-value>mqtt://your-app-id:ttn-account-v2.theauthtoken-that-issupplied-by-ttn@eu:8883</param-value>
</context-param>

The handler specifies which class should be instantiated and invoked whenever a message arrives via this connection. This class has to implement the at.tspi.ttnclientj2.client.TTNMessageHandler interface. This interface provides an initializeHandler routine that can be used to configure the handler from the ServletContextEvent that has been passed to the context listener and an handler function (handleTTNMessage) that gets invoked on every received packet.

<context-param>
	<param-name>con1-handler</param-name>
	<param-value>com.example.handlers.MyHandlerClass</param-value>
</context-param>

The packets are passed as TTNMessage. Various types of messages exist:

• TTN Device Events:
  • TTNDeviceEventActivation is invoked whenever an device is activated (for example via OTAA)
  • TTNDeviceEventCreated is invoked whenever a new device is created in the console or via the API
  • TTNDeviceEventDeleted is the counterpart to the created event.
  • TTNDeviceEventUpdated
  • TTNDeviceEventDownlinkAck
  • TTNDeviceEventDownlinkSheduled
  • TTNDownlinkSent
  • TTNDeviceEventErrorActivation
  • TTNDeviceEventErrorDownlink
  • TTNDeviceEventErrorUplink
• TTNMessageUplink is the message container that contains a normal received message as well as all associated metadata (inside an UplinkMetadata object
• TTNMessageDownlink is the only container that gets instantiated by the application itself - it is used by the send routine of the TTNClient implementations.

Simple usage example

To be done