Split out statistics tracking into separate classes
[controller.git] / opendaylight / md-sal / statistics-manager / src / main / java / org / opendaylight / controller / md / statistics / manager / StatisticsProvider.java
index f2b181cf4703fc9d1621073bf4611b644c17fd0d..e9d2356cf9552f560b582747e6f3c66a59452cb3 100644 (file)
@@ -7,23 +7,27 @@
  */
 package org.opendaylight.controller.md.statistics.manager;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.Collection;
+import java.util.Timer;
+import java.util.TimerTask;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
 
-import org.eclipse.xtext.xbase.lib.Exceptions;
 import org.opendaylight.controller.md.statistics.manager.MultipartMessageManager.StatsRequestType;
 import org.opendaylight.controller.sal.binding.api.NotificationProviderService;
+import org.opendaylight.controller.sal.binding.api.RpcConsumerRegistry;
 import org.opendaylight.controller.sal.binding.api.data.DataBrokerService;
+import org.opendaylight.controller.sal.binding.api.data.DataChangeListener;
 import org.opendaylight.controller.sal.binding.api.data.DataModificationTransaction;
 import org.opendaylight.controller.sal.binding.api.data.DataProviderService;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowCapableNode;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowCapableNodeConnector;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.meters.Meter;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.Table;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.TableKey;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.Flow;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.statistics.rev130819.GetAggregateFlowStatisticsFromFlowTableForAllFlowsInputBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.statistics.rev130819.GetAggregateFlowStatisticsFromFlowTableForAllFlowsOutput;
@@ -63,6 +67,7 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.queue.statistics.rev131216.
 import org.opendaylight.yang.gen.v1.urn.opendaylight.queue.statistics.rev131216.GetQueueStatisticsFromGivenPortInputBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.queue.statistics.rev131216.GetQueueStatisticsFromGivenPortOutput;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.queue.statistics.rev131216.OpendaylightQueueStatisticsService;
+import org.opendaylight.yangtools.concepts.ListenerRegistration;
 import org.opendaylight.yangtools.concepts.Registration;
 import org.opendaylight.yangtools.yang.binding.DataObject;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
@@ -71,6 +76,8 @@ import org.opendaylight.yangtools.yang.common.RpcResult;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import com.google.common.base.Preconditions;
+
 /**
  * Following are main responsibilities of the class:
  * 1) Invoke statistics request thread to send periodic statistics request to all the
@@ -84,14 +91,14 @@ import org.slf4j.LoggerFactory;
  *
  */
 public class StatisticsProvider implements AutoCloseable {
+    public static final long STATS_COLLECTION_MILLIS = TimeUnit.SECONDS.toMillis(15);
 
-    public final static Logger spLogger = LoggerFactory.getLogger(StatisticsProvider.class);
-
-    private DataProviderService dps;
+    private static final Logger spLogger = LoggerFactory.getLogger(StatisticsProvider.class);
 
-    private DataBrokerService dbs;
-
-    private NotificationProviderService nps;
+    private final ConcurrentMap<NodeId, NodeStatisticsHandler> handlers = new ConcurrentHashMap<>();
+    private final MultipartMessageManager multipartMessageManager = new MultipartMessageManager();
+    private final Timer timer = new Timer("statistics-manager", true);
+    private final DataProviderService dps;
 
     private OpendaylightGroupStatisticsService groupStatsService;
 
@@ -105,134 +112,72 @@ public class StatisticsProvider implements AutoCloseable {
 
     private OpendaylightQueueStatisticsService queueStatsService;
 
-    private final MultipartMessageManager multipartMessageManager = new MultipartMessageManager();
-
     private StatisticsUpdateHandler statsUpdateHandler;
 
-    private Thread statisticsRequesterThread;
-
-    private Thread statisticsAgerThread;
-
-    private final  InstanceIdentifier<Nodes> nodesIdentifier = InstanceIdentifier.builder(Nodes.class).toInstance();
-
-    public static final int STATS_THREAD_EXECUTION_TIME= 15000;
-    //Local caching of stats
-
-    private final ConcurrentMap<NodeId,NodeStatisticsAger> statisticsCache =
-            new ConcurrentHashMap<NodeId,NodeStatisticsAger>();
-
-    public DataProviderService getDataService() {
-      return this.dps;
-    }
-
-    public void setDataService(final DataProviderService dataService) {
-      this.dps = dataService;
-    }
-
-    public DataBrokerService getDataBrokerService() {
-        return this.dbs;
-    }
-
-    public void setDataBrokerService(final DataBrokerService dataBrokerService) {
-        this.dbs = dataBrokerService;
-    }
-
-    public NotificationProviderService getNotificationService() {
-      return this.nps;
-    }
-
-    public void setNotificationService(final NotificationProviderService notificationService) {
-      this.nps = notificationService;
+    public StatisticsProvider(final DataProviderService dataService) {
+        this.dps = Preconditions.checkNotNull(dataService);
     }
 
     public MultipartMessageManager getMultipartMessageManager() {
         return multipartMessageManager;
     }
 
-    private final StatisticsUpdateCommiter updateCommiter = new StatisticsUpdateCommiter(StatisticsProvider.this);
+    private final StatisticsListener updateCommiter = new StatisticsListener(StatisticsProvider.this);
 
     private Registration<NotificationListener> listenerRegistration;
 
-    public void start() {
-
-        NotificationProviderService nps = this.getNotificationService();
-        Registration<NotificationListener> registerNotificationListener = nps.registerNotificationListener(this.updateCommiter);
-        this.listenerRegistration = registerNotificationListener;
-
-        statsUpdateHandler = new StatisticsUpdateHandler(StatisticsProvider.this);
-
-        registerDataStoreUpdateListener(this.getDataBrokerService());
+    private ListenerRegistration<DataChangeListener> flowCapableTrackerRegistration;
 
-        // Get Group/Meter statistics service instance
-        groupStatsService = StatisticsManagerActivator.getProviderContext().
-                getRpcService(OpendaylightGroupStatisticsService.class);
+    public void start(final DataBrokerService dbs, final NotificationProviderService nps, final RpcConsumerRegistry rpcRegistry) {
 
-        meterStatsService = StatisticsManagerActivator.getProviderContext().
-                getRpcService(OpendaylightMeterStatisticsService.class);
+        // Get Group/Meter statistics service instances
+        groupStatsService = rpcRegistry.getRpcService(OpendaylightGroupStatisticsService.class);
+        meterStatsService = rpcRegistry.getRpcService(OpendaylightMeterStatisticsService.class);
+        flowStatsService = rpcRegistry.getRpcService(OpendaylightFlowStatisticsService.class);
+        portStatsService = rpcRegistry.getRpcService(OpendaylightPortStatisticsService.class);
+        flowTableStatsService = rpcRegistry.getRpcService(OpendaylightFlowTableStatisticsService.class);
+        queueStatsService = rpcRegistry.getRpcService(OpendaylightQueueStatisticsService.class);
 
-        flowStatsService = StatisticsManagerActivator.getProviderContext().
-                getRpcService(OpendaylightFlowStatisticsService.class);
+        // Start receiving notifications
+        this.listenerRegistration = nps.registerNotificationListener(this.updateCommiter);
 
-        portStatsService = StatisticsManagerActivator.getProviderContext().
-                getRpcService(OpendaylightPortStatisticsService.class);
+        // Register for switch connect/disconnect notifications
+        final InstanceIdentifier<FlowCapableNode> fcnId = InstanceIdentifier.builder(Nodes.class)
+                .child(Node.class).augmentation(FlowCapableNode.class).build();
+        spLogger.debug("Registering FlowCapable tracker to {}", fcnId);
+        this.flowCapableTrackerRegistration = dbs.registerDataChangeListener(fcnId,
+                new FlowCapableTracker(this, fcnId));
 
-        flowTableStatsService = StatisticsManagerActivator.getProviderContext().
-                getRpcService(OpendaylightFlowTableStatisticsService.class);
-
-        queueStatsService = StatisticsManagerActivator.getProviderContext().
-                getRpcService(OpendaylightQueueStatisticsService.class);
-
-        statisticsRequesterThread = new Thread( new Runnable(){
+        statsUpdateHandler = new StatisticsUpdateHandler(StatisticsProvider.this);
+        registerDataStoreUpdateListener(dbs);
 
+        timer.schedule(new TimerTask() {
             @Override
             public void run() {
-                while(true){
-                    try {
-                        statsRequestSender();
-
-                        Thread.sleep(STATS_THREAD_EXECUTION_TIME);
-                    }catch (Exception e){
-                        spLogger.error("Exception occurred while sending stats request : {}",e);
+                try {
+                    // Send stats requests
+                    for (NodeStatisticsHandler h : handlers.values()) {
+                        sendStatisticsRequestsToNode(h);
                     }
-                }
-            }
-        });
-
-        spLogger.debug("Statistics requester thread started with timer interval : {}",STATS_THREAD_EXECUTION_TIME);
 
-        statisticsRequesterThread.start();
-
-        statisticsAgerThread = new Thread( new Runnable(){
-
-            @Override
-            public void run() {
-                while(true){
-                    try {
-                        for(NodeStatisticsAger nodeStatisticsAger : statisticsCache.values()){
-                            nodeStatisticsAger.cleanStaleStatistics();
-                        }
-                        multipartMessageManager.cleanStaleTransactionIds();
-
-                        Thread.sleep(STATS_THREAD_EXECUTION_TIME);
-                    }catch (Exception e){
-                        spLogger.error("Exception occurred while sending stats request : {}",e);
+                    // Perform cleanup
+                    for(NodeStatisticsHandler nodeStatisticsAger : handlers.values()){
+                        nodeStatisticsAger.cleanStaleStatistics();
                     }
+
+                    multipartMessageManager.cleanStaleTransactionIds();
+                } catch (RuntimeException e) {
+                    spLogger.warn("Failed to request statistics", e);
                 }
             }
-        });
-
-        spLogger.debug("Statistics ager thread started with timer interval : {}",STATS_THREAD_EXECUTION_TIME);
-
-        statisticsAgerThread.start();
+        }, 0, STATS_COLLECTION_MILLIS);
 
+        spLogger.debug("Statistics timer task with timer interval : {}ms", STATS_COLLECTION_MILLIS);
         spLogger.info("Statistics Provider started.");
     }
 
     private void registerDataStoreUpdateListener(DataBrokerService dbs) {
-        //Register for Node updates
-        InstanceIdentifier<? extends DataObject> pathNode = InstanceIdentifier.builder(Nodes.class)
-                                                                        .child(Node.class).toInstance();
-        dbs.registerDataChangeListener(pathNode, statsUpdateHandler);
+        // FIXME: the below should be broken out into StatisticsUpdateHandler
 
         //Register for flow updates
         InstanceIdentifier<? extends DataObject> pathFlow = InstanceIdentifier.builder(Nodes.class).child(Node.class)
@@ -263,56 +208,37 @@ public class StatisticsProvider implements AutoCloseable {
     }
 
     protected DataModificationTransaction startChange() {
-
-        DataProviderService dps = this.getDataService();
         return dps.beginTransaction();
     }
 
-    private void statsRequestSender(){
-
-        List<Node> targetNodes = getAllConnectedNodes();
-
-        if(targetNodes == null)
-            return;
-
-
-        for (Node targetNode : targetNodes){
-
-            if(targetNode.getAugmentation(FlowCapableNode.class) != null){
-                sendStatisticsRequestsToNode(targetNode);
-            }
-        }
-    }
-
-    public void sendStatisticsRequestsToNode(Node targetNode){
-
-        spLogger.debug("Send requests for statistics collection to node : {})",targetNode.getId());
-
-        InstanceIdentifier<Node> targetInstanceId = InstanceIdentifier.builder(Nodes.class).child(Node.class,targetNode.getKey()).toInstance();
-
-        NodeRef targetNodeRef = new NodeRef(targetInstanceId);
+    private void sendStatisticsRequestsToNode(final NodeStatisticsHandler h) {
+        NodeKey targetNode = h.getTargetNodeKey();
+        spLogger.debug("Send requests for statistics collection to node : {}", targetNode.getId());
 
         try{
-            if(flowStatsService != null){
-                sendAggregateFlowsStatsFromAllTablesRequest(targetNode.getKey());
-                sendAllFlowsStatsFromAllTablesRequest(targetNodeRef);
-            }
             if(flowTableStatsService != null){
-                sendAllFlowTablesStatisticsRequest(targetNodeRef);
+                sendAllFlowTablesStatisticsRequest(h);
+            }
+            if(flowStatsService != null){
+                // FIXME: it does not make sense to trigger this before sendAllFlowTablesStatisticsRequest()
+                //        comes back -- we do not have any tables anyway.
+                sendAggregateFlowsStatsFromAllTablesRequest(h);
+
+                sendAllFlowsStatsFromAllTablesRequest(h);
             }
             if(portStatsService != null){
-                sendAllNodeConnectorsStatisticsRequest(targetNodeRef);
+                sendAllNodeConnectorsStatisticsRequest(h);
             }
             if(groupStatsService != null){
-                sendAllGroupStatisticsRequest(targetNodeRef);
-                sendGroupDescriptionRequest(targetNodeRef);
+                sendAllGroupStatisticsRequest(h);
+                sendGroupDescriptionRequest(h);
             }
             if(meterStatsService != null){
-                sendAllMeterStatisticsRequest(targetNodeRef);
-                sendMeterConfigStatisticsRequest(targetNodeRef);
+                sendAllMeterStatisticsRequest(h);
+                sendMeterConfigStatisticsRequest(h);
             }
             if(queueStatsService != null){
-                sendAllQueueStatsFromAllNodeConnector (targetNodeRef);
+                sendAllQueueStatsFromAllNodeConnector(h);
             }
         }catch(Exception e){
             spLogger.error("Exception occured while sending statistics requests : {}", e);
@@ -320,64 +246,65 @@ public class StatisticsProvider implements AutoCloseable {
     }
 
 
-    public void sendAllFlowTablesStatisticsRequest(NodeRef targetNodeRef) throws InterruptedException, ExecutionException {
+    private void sendAllFlowTablesStatisticsRequest(NodeStatisticsHandler h) throws InterruptedException, ExecutionException {
         final GetFlowTablesStatisticsInputBuilder input =
                 new GetFlowTablesStatisticsInputBuilder();
 
-        input.setNode(targetNodeRef);
+        input.setNode(h.getTargetNodeRef());
 
         Future<RpcResult<GetFlowTablesStatisticsOutput>> response =
                 flowTableStatsService.getFlowTablesStatistics(input.build());
 
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNodeRef),response.get().getResult().getTransactionId()
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(),response.get().getResult().getTransactionId()
                 , StatsRequestType.ALL_FLOW_TABLE);
 
     }
 
-    public void sendAllFlowsStatsFromAllTablesRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
+    private void sendAllFlowsStatsFromAllTablesRequest(NodeStatisticsHandler h) throws InterruptedException, ExecutionException{
         final GetAllFlowsStatisticsFromAllFlowTablesInputBuilder input =
                 new GetAllFlowsStatisticsFromAllFlowTablesInputBuilder();
 
-        input.setNode(targetNode);
+        input.setNode(h.getTargetNodeRef());
 
         Future<RpcResult<GetAllFlowsStatisticsFromAllFlowTablesOutput>> response =
                 flowStatsService.getAllFlowsStatisticsFromAllFlowTables(input.build());
 
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(), response.get().getResult().getTransactionId()
                 , StatsRequestType.ALL_FLOW);
 
     }
 
-    public void sendFlowStatsFromTableRequest(NodeRef targetNode,Flow flow) throws InterruptedException, ExecutionException{
+    public void sendFlowStatsFromTableRequest(NodeKey node, Flow flow) throws InterruptedException, ExecutionException {
+        final NodeStatisticsHandler h = getStatisticsHandler(node.getId());
+        if (h != null) {
+            sendFlowStatsFromTableRequest(h, flow);
+        }
+    }
+
+    private void sendFlowStatsFromTableRequest(NodeStatisticsHandler h, Flow flow) throws InterruptedException, ExecutionException{
         final GetFlowStatisticsFromFlowTableInputBuilder input =
                 new GetFlowStatisticsFromFlowTableInputBuilder();
 
-        input.setNode(targetNode);
+        input.setNode(h.getTargetNodeRef());
         input.fieldsFrom(flow);
 
         Future<RpcResult<GetFlowStatisticsFromFlowTableOutput>> response =
                 flowStatsService.getFlowStatisticsFromFlowTable(input.build());
 
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_FLOW);
-
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(),
+                response.get().getResult().getTransactionId(), StatsRequestType.ALL_FLOW);
     }
 
-    public void sendAggregateFlowsStatsFromAllTablesRequest(NodeKey targetNodeKey) throws InterruptedException, ExecutionException{
-
-        List<Short> tablesId = getTablesFromNode(targetNodeKey);
+    private void sendAggregateFlowsStatsFromAllTablesRequest(final NodeStatisticsHandler h) throws InterruptedException, ExecutionException{
+        final Collection<TableKey> tables = h.getKnownTables();
+        spLogger.debug("Node {} supports {} table(s)", h, tables.size());
 
-        if(tablesId.size() != 0){
-            for(Short id : tablesId){
-
-                sendAggregateFlowsStatsFromTableRequest(targetNodeKey,id);
-            }
-        }else{
-            spLogger.debug("No details found in data store for flow tables associated with Node {}",targetNodeKey);
+        for (TableKey key : h.getKnownTables()) {
+            sendAggregateFlowsStatsFromTableRequest(h.getTargetNodeKey(), key.getId().shortValue());
         }
     }
 
-    public void sendAggregateFlowsStatsFromTableRequest(NodeKey targetNodeKey,Short tableId) throws InterruptedException, ExecutionException{
+    private void sendAggregateFlowsStatsFromTableRequest(NodeKey targetNodeKey,Short tableId) throws InterruptedException, ExecutionException{
 
         spLogger.debug("Send aggregate stats request for flow table {} to node {}",tableId,targetNodeKey);
         GetAggregateFlowStatisticsFromFlowTableForAllFlowsInputBuilder input =
@@ -393,159 +320,182 @@ public class StatisticsProvider implements AutoCloseable {
                 , StatsRequestType.AGGR_FLOW);
     }
 
-    public void sendAllNodeConnectorsStatisticsRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
+    private void sendAllNodeConnectorsStatisticsRequest(NodeStatisticsHandler h) throws InterruptedException, ExecutionException{
 
         final GetAllNodeConnectorsStatisticsInputBuilder input = new GetAllNodeConnectorsStatisticsInputBuilder();
 
-        input.setNode(targetNode);
+        input.setNode(h.getTargetNodeRef());
 
         Future<RpcResult<GetAllNodeConnectorsStatisticsOutput>> response =
                 portStatsService.getAllNodeConnectorsStatistics(input.build());
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(), response.get().getResult().getTransactionId()
                 , StatsRequestType.ALL_PORT);
 
     }
 
-    public void sendAllGroupStatisticsRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
+    private void sendAllGroupStatisticsRequest(NodeStatisticsHandler h) throws InterruptedException, ExecutionException{
 
         final GetAllGroupStatisticsInputBuilder input = new GetAllGroupStatisticsInputBuilder();
 
-        input.setNode(targetNode);
+        input.setNode(h.getTargetNodeRef());
 
         Future<RpcResult<GetAllGroupStatisticsOutput>> response =
                 groupStatsService.getAllGroupStatistics(input.build());
 
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(), response.get().getResult().getTransactionId()
                 , StatsRequestType.ALL_GROUP);
 
     }
 
-    public void sendGroupDescriptionRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
+    public void sendGroupDescriptionRequest(NodeKey node) throws InterruptedException, ExecutionException{
+        final NodeStatisticsHandler h = getStatisticsHandler(node.getId());
+        if (h != null) {
+            sendGroupDescriptionRequest(h);
+        }
+    }
+
+    private void sendGroupDescriptionRequest(NodeStatisticsHandler h) throws InterruptedException, ExecutionException{
         final GetGroupDescriptionInputBuilder input = new GetGroupDescriptionInputBuilder();
 
-        input.setNode(targetNode);
+        input.setNode(h.getTargetNodeRef());
 
         Future<RpcResult<GetGroupDescriptionOutput>> response =
                 groupStatsService.getGroupDescription(input.build());
 
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.GROUP_DESC);
-
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(),
+                response.get().getResult().getTransactionId(), StatsRequestType.GROUP_DESC);
     }
 
-    public void sendAllMeterStatisticsRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
+    private void sendAllMeterStatisticsRequest(NodeStatisticsHandler h) throws InterruptedException, ExecutionException{
 
         GetAllMeterStatisticsInputBuilder input = new GetAllMeterStatisticsInputBuilder();
 
-        input.setNode(targetNode);
+        input.setNode(h.getTargetNodeRef());
 
         Future<RpcResult<GetAllMeterStatisticsOutput>> response =
                 meterStatsService.getAllMeterStatistics(input.build());
 
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(), response.get().getResult().getTransactionId()
                 , StatsRequestType.ALL_METER);;
 
     }
 
-    public void sendMeterConfigStatisticsRequest(NodeRef targetNode) throws InterruptedException, ExecutionException{
+    public void sendMeterConfigStatisticsRequest(NodeKey node) throws InterruptedException, ExecutionException {
+        final NodeStatisticsHandler h = getStatisticsHandler(node.getId());
+        if (h != null) {
+            sendMeterConfigStatisticsRequest(h);
+        }
+    }
+
+    private void sendMeterConfigStatisticsRequest(NodeStatisticsHandler h) throws InterruptedException, ExecutionException{
 
         GetAllMeterConfigStatisticsInputBuilder input = new GetAllMeterConfigStatisticsInputBuilder();
 
-        input.setNode(targetNode);
+        input.setNode(h.getTargetNodeRef());
 
         Future<RpcResult<GetAllMeterConfigStatisticsOutput>> response =
                 meterStatsService.getAllMeterConfigStatistics(input.build());
 
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.METER_CONFIG);;
-
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(),
+                response.get().getResult().getTransactionId(), StatsRequestType.METER_CONFIG);;
     }
 
-    public void sendAllQueueStatsFromAllNodeConnector(NodeRef targetNode) throws InterruptedException, ExecutionException {
+    private void sendAllQueueStatsFromAllNodeConnector(NodeStatisticsHandler h) throws InterruptedException, ExecutionException {
         GetAllQueuesStatisticsFromAllPortsInputBuilder input = new GetAllQueuesStatisticsFromAllPortsInputBuilder();
 
-        input.setNode(targetNode);
+        input.setNode(h.getTargetNodeRef());
 
         Future<RpcResult<GetAllQueuesStatisticsFromAllPortsOutput>> response =
                 queueStatsService.getAllQueuesStatisticsFromAllPorts(input.build());
 
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_QUEUE_STATS);;
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(),
+                response.get().getResult().getTransactionId(), StatsRequestType.ALL_QUEUE_STATS);;
+    }
 
+    public void sendQueueStatsFromGivenNodeConnector(NodeKey node,NodeConnectorId nodeConnectorId, QueueId queueId) throws InterruptedException, ExecutionException {
+        final NodeStatisticsHandler h = getStatisticsHandler(node.getId());
+        if (h != null) {
+            sendQueueStatsFromGivenNodeConnector(h, nodeConnectorId, queueId);
+        }
     }
 
-    public void sendQueueStatsFromGivenNodeConnector(NodeRef targetNode,NodeConnectorId nodeConnectorId, QueueId queueId) throws InterruptedException, ExecutionException {
+    private void sendQueueStatsFromGivenNodeConnector(NodeStatisticsHandler h, NodeConnectorId nodeConnectorId, QueueId queueId) throws InterruptedException, ExecutionException {
         GetQueueStatisticsFromGivenPortInputBuilder input = new GetQueueStatisticsFromGivenPortInputBuilder();
 
-        input.setNode(targetNode);
+        input.setNode(h.getTargetNodeRef());
         input.setNodeConnectorId(nodeConnectorId);
         input.setQueueId(queueId);
         Future<RpcResult<GetQueueStatisticsFromGivenPortOutput>> response =
                 queueStatsService.getQueueStatisticsFromGivenPort(input.build());
 
-        this.multipartMessageManager.addTxIdToRequestTypeEntry(getNodeId(targetNode), response.get().getResult().getTransactionId()
-                , StatsRequestType.ALL_QUEUE_STATS);;
-
+        this.multipartMessageManager.addTxIdToRequestTypeEntry(h.getTargetNodeKey().getId(),
+                response.get().getResult().getTransactionId(), StatsRequestType.ALL_QUEUE_STATS);;
     }
 
-    public final NodeStatisticsAger getStatisticsAger(final NodeId nodeId) {
-        NodeStatisticsAger ager = statisticsCache.get(nodeId);
-        if (ager == null) {
-            ager = new NodeStatisticsAger(this, new NodeKey(nodeId));
-            statisticsCache.put(nodeId, ager);
+    /**
+     * Get the handler for a particular node.
+     *
+     * @param nodeId source node
+     * @return Node statistics handler for that node. Null if the statistics should
+     *         not handled.
+     */
+    public final NodeStatisticsHandler getStatisticsHandler(final NodeId nodeId) {
+        Preconditions.checkNotNull(nodeId);
+        NodeStatisticsHandler handler = handlers.get(nodeId);
+        if (handler == null) {
+            spLogger.info("Attempted to get non-existing handler for {}", nodeId);
         }
-
-        return ager;
+        return handler;
     }
 
-    private List<Node> getAllConnectedNodes(){
-        Nodes nodes = (Nodes) dps.readOperationalData(nodesIdentifier);
-        if(nodes == null)
-            return null;
-
-        spLogger.debug("Number of connected nodes : {}",nodes.getNode().size());
-        return nodes.getNode();
-    }
-
-    private List<Short> getTablesFromNode(NodeKey nodeKey){
-        InstanceIdentifier<FlowCapableNode> nodesIdentifier = InstanceIdentifier.builder(Nodes.class).child(Node.class,nodeKey).augmentation(FlowCapableNode.class).toInstance();
-
-        FlowCapableNode node = (FlowCapableNode)dps.readOperationalData(nodesIdentifier);
-        List<Short> tablesId = new ArrayList<Short>();
-        if(node != null && node.getTable()!=null){
-            spLogger.debug("Number of tables {} supported by node {}",node.getTable().size(),nodeKey);
-            for(Table table: node.getTable()){
-                tablesId.add(table.getId());
-            }
-        }
-        return tablesId;
-    }
-
-    @SuppressWarnings("unchecked")
-    private NodeId getNodeId(NodeRef nodeRef){
-        InstanceIdentifier<Node> nodeII = (InstanceIdentifier<Node>) nodeRef.getValue();
-        NodeKey nodeKey = InstanceIdentifier.keyOf(nodeII);
-        return nodeKey.getId();
-    }
-
-    @SuppressWarnings("deprecation")
     @Override
-    public void close(){
-
+    public void close() {
         try {
-            spLogger.info("Statistics Provider stopped.");
             if (this.listenerRegistration != null) {
-
                 this.listenerRegistration.close();
+                this.listenerRegistration = null;
+            }
+            if (this.flowCapableTrackerRegistration != null) {
+                this.flowCapableTrackerRegistration.close();
+                this.flowCapableTrackerRegistration = null;
+            }
+            timer.cancel();
+        } catch (Exception e) {
+            spLogger.warn("Failed to stop Statistics Provider completely", e);
+        } finally {
+            spLogger.info("Statistics Provider stopped.");
+        }
+    }
 
-                this.statisticsRequesterThread.destroy();
+    void startNodeHandlers(final Collection<NodeKey> addedNodes) {
+        for (NodeKey key : addedNodes) {
+            if (handlers.containsKey(key.getId())) {
+                spLogger.warn("Attempted to start already-existing handler for {}, very strange", key.getId());
+                continue;
+            }
 
-                this.statisticsAgerThread.destroy();
+            final NodeStatisticsHandler h = new NodeStatisticsHandler(dps, key);
+            final NodeStatisticsHandler old = handlers.putIfAbsent(key.getId(), h);
+            if (old == null) {
+                spLogger.debug("Started node handler for {}", key.getId());
 
+                // FIXME: this should be in the NodeStatisticsHandler itself
+                sendStatisticsRequestsToNode(h);
+            } else {
+                spLogger.debug("Prevented race on handler for {}", key.getId());
             }
-          } catch (Throwable e) {
-            throw Exceptions.sneakyThrow(e);
-          }
+        }
     }
 
+    void stopNodeHandlers(final Collection<NodeKey> removedNodes) {
+        for (NodeKey key : removedNodes) {
+            final NodeStatisticsHandler s = handlers.remove(key.getId());
+            if (s != null) {
+                spLogger.debug("Stopping node handler for {}", key.getId());
+                s.close();
+            } else {
+                spLogger.warn("Attempted to remove non-existing handler for {}, very strange", key.getId());
+            }
+        }
+    }
 }