** add reference to OSGI Declarative Service (DS)
*** in ''OSGI-INF/org.openhab.binding.marlinfireplace.internal.MarlinFireplaceHandlerFactory.xml'' add <pre> <<reference bind="setMqttService" cardinality="1..1" interface="org.openhab.io.transport.mqtt.MqttService" name="MqttService" policy="static" unbind="unsetMqttService"/>> </pre>
** implement the methods in the named class (this case ''org.openhab.binding.marlinfireplace.internal.MarlinFireplaceHandlerFactory'')
** <pre>public void setMqttService(MqttService mqttService) {}; public void unsetMqttService(MqttService mqttService) </pre>