Address PR 207 comments

core/src/main/kotlin/net/corda/core/messaging/CordaRPCOps.kt

@@ -112,9 +112,10 @@ interface CordaRPCOps : RPCOps {
     fun currentNodeTime(): Instant
 
     /**
-     * Returns whether the node has registered with the network map.
+     * Returns an Observable emitting a single Unit once the node is registered with the network map.
      */
-    fun isRegisteredWithNetworkMap(): Boolean
+    @RPCReturnsObservables
+    fun waitUntilRegisteredWithNetworkMap(): Observable<Unit>
 
     // TODO These need rethinking. Instead of these direct calls we should have a way of replicating a subset of
     // the node's state locally and query that directly.

node/src/main/kotlin/net/corda/node/driver/Driver.kt

@@ -334,7 +334,7 @@ open class DriverDSL(
                 client.start(ArtemisMessagingComponent.NODE_USER, ArtemisMessagingComponent.NODE_USER)
                 return@poll client.proxy()
             } catch(e: Exception) {
-                log.error("Retrying query node info at $nodeAddress")
+                log.error("Exception $e, Retrying RPC connection at $nodeAddress")
                 null
             }
         }
@@ -380,12 +380,8 @@ open class DriverDSL(
         registerProcess(processFuture)
         return processFuture.flatMap { process ->
             establishRpc(messagingAddress, configuration).flatMap { rpc ->
-                poll(executorService, "$name to register with the network map") {
-                    if (rpc.isRegisteredWithNetworkMap()) {
-                        NodeHandle(rpc.nodeIdentity(), rpc, configuration, process)
-                    } else {
-                        null
-                    }
+                rpc.waitUntilRegisteredWithNetworkMap().toFuture().map {
+                    NodeHandle(rpc.nodeIdentity(), rpc, configuration, process)
                 }
             }
         }

node/src/main/kotlin/net/corda/node/internal/CordaRPCOpsImpl.kt

@@ -111,8 +111,7 @@ class CordaRPCOpsImpl(
         }
     }
 
-    override fun isRegisteredWithNetworkMap() = services.networkMapCache.mapServiceRegistered.isDone
-
+    override fun waitUntilRegisteredWithNetworkMap() = services.networkMapCache.mapServiceRegistered.toObservable()
     override fun partyFromKey(key: CompositeKey) = services.identityService.partyFromKey(key)
     override fun partyFromName(name: String) = services.identityService.partyFromName(name)