sdk-dslink-scala
DSLink Scala SDK
Features
- Provides DSAConnector and DSAConnection classes as a communication facade.
- Tracks DSA connection lifecycle through DSAEventListener interface.
- Implements DSAHelper object for basic DSA operations, such as invoke, subscribe, set, etc.
- Exposes DSA API through Reactive Streams paradigm.
- Implements fluent Scala layer to facilitate operations with DSA artifacts.
- Recognizes all existing Node API data types.
Usage
DSAConnector
You can create a DSAConnector passing individual settings or the entire argument list:
val brokerUrl = ...
val configPath = ...
val connector = DSAConnector("-b", brokerUrl, "-d", configPath)
or
def main(args: Array[String]): Unit = {
val connector = DSAConnector(args)
}
You can then add listeners and initiate a new connection do DSA:
connector.addListener(new DSAEventListener {
override def onResponderConnected(link: DSLink) = println("responder link connected @ " + link.getPath)
})
val connection = connector.start(RESPONDER)
val root = connection.responderLink.getNodeManager.getSuperRoot
root createChild "counter" valueType ValueType.NUMBER value 0 build ()
...
connector.stop
DSAHelper
Most DSAHelper methods require implicit Requester or Responder object. You can use the ones provided by DSAConnection:
val connection = connector start LinkMode.DUAL
implicit val requester = connection.requester
implicit val responder = connection.responder
Example calling DSA Invoke method:
DSAHelper invoke (path, key1 -> value1, key2 -> value2) subscribe (
onNext = event => println("Event received: " + event),
onError = err => println("Error occurred: " + err),
onCompleted = () => println("Stream closed, no more data")
)
Example calling DSA Subscribe on multiple nodes and merging the results:
val cpu = DSAHelper watch "/downstream/System/CPU_Usage"
val mem = DSAHelper watch "/downstream/System/Memory_Usage"
cpu merge mem subscribe { sv =>
println(sv.getPath + " : " + sv.getValue)
}
Note that you can subscribe to the same path multiple times using watch without raising an error.
Node Builder
This SDK also provides an extension to the Java NodeBuilder class to expose a simple DSL.
Example creating new nodes:
parentNode createChild "changeValue" display "Update Value" action (
createAction(
parameters = List("value" -> ValueType.NUMBER),
handler = result => {
val value = result.getParameter("value").getNumber
DSAHelper updateNode "/output/value" -> value
}
)
) build
