Persistence Implementation when creating a mqtt client

[Gathika94]

Description:
In the MqttSink.java[1] class,
in the connect() method (line number 205),
an instance of MqttDefaultFilePersistence is created as persistence (line number 207).

MqttDefaultFilePersistence persistence = new MqttDefaultFilePersistence(); (207)

It is passed in as the persistence argument to the MqttClient(brokerURL, clientId, persistence) constructor (line number 211).

client = new MqttClient(brokerURL, clientId, persistence); (211)

MqttDefaultFilePersistence persist data in 'user.dir'. But when these configurations are given to an Android app, the app does not have the permissions to write in that directory. As a result it gives runtime error.

When creating a new mqtt client if null is passed in as the value for the persistence argument and it has worked correctly.

MqttClient(brokerURL, clientId, null);

So if there is a parameter in Siddhi Sink to determine which value to be passed in as the persistence argument (an instance of MqttDefaultFilePersistence or null) when a new client is creating, this issue can be overcome.

Suggested Labels:
Android, Siddhi, Mqtt

OS, DB, other environment details and versions:
Android OS