Merge into master from pull request #3770:

BSC-3926. Set switch's connectedSince when the switch is actually connected. Set to null otherwise. (https://github.com/bigswitch/bigswitchcontroller/pull/3770)

src/main/java/net/floodlightcontroller/core/OFSwitchBase.java

@@ -94,7 +94,8 @@ public abstract class OFSwitchBase implements IOFSwitch {
     protected IFloodlightProviderService floodlightProvider;
     protected IThreadPoolService threadPool;
     protected IDebugCounterService debugCounters;
-    protected Date connectedSince;
+    // FIXME: Don't use java.util.Date
+    protected volatile Date connectedSince;
 
     /* Switch features from initial featuresReply */
     protected int capabilities;
@@ -169,7 +170,7 @@ public abstract class OFSwitchBase implements IOFSwitch {
     public OFSwitchBase() {
         this.stringId = null;
         this.attributes = new ConcurrentHashMap<Object, Object>();
-        this.connectedSince = new Date();
+        this.connectedSince = null;
         this.transactionIdSource = new AtomicInteger();
         this.connected = false;
         this.statsFutureMap = new ConcurrentHashMap<Integer,OFStatisticsFuture>();
@@ -1093,6 +1094,10 @@ public abstract class OFSwitchBase implements IOFSwitch {
     @JsonIgnore
     public void setConnected(boolean connected) {
         // No lock needed since we use volatile
+        if (connected && this.connectedSince == null)
+            this.connectedSince = new Date();
+        else if (!connected)
+            this.connectedSince = null;
         this.connected = connected;
     }
 

src/main/java/net/floodlightcontroller/core/web/ControllerSwitchesResource.java

@@ -92,6 +92,8 @@ public class ControllerSwitchesResource extends ServerResource {
         }
 
         public long getConnectedSince() {
+            if (sw.getConnectedSince() == null)
+                return 0;
             return sw.getConnectedSince().getTime();
         }