Add Null/ClassCastException checks to the event history REST APIs.

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

@@ -10,12 +10,17 @@ import net.floodlightcontroller.util.EventHistory;
 
 import org.restlet.resource.ServerResource;
 import org.restlet.resource.Get;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * @author subrata
  *
  */
 public class EventHistoryAttachmentPointResource extends ServerResource {
+    // TODO - Move this to the DeviceManager Rest API
+    protected static Logger log = 
+            LoggerFactory.getLogger(EventHistoryAttachmentPointResource.class);
     /***
      * Event History Names:
      *     (a) attachment-point
@@ -42,11 +47,18 @@ public class EventHistoryAttachmentPointResource extends ServerResource {
             // Invalid input for event count - use default value
         }
 
-        DeviceManagerImpl deviceManager = 
-           (DeviceManagerImpl)getContext().getAttributes().
-               get(IDeviceManagerService.class.getCanonicalName());
+        try {
+            DeviceManagerImpl deviceManager = 
+               (DeviceManagerImpl)getContext().getAttributes().
+                   get(IDeviceManagerService.class.getCanonicalName());
+            if (deviceManager != null) {
+                return new EventHistory<EventHistoryAttachmentPoint>(
+                        deviceManager.evHistDevMgrAttachPt, count);
+            }
+        } catch (ClassCastException e) {
+            log.error(e.toString());
+        }
 
-        return new EventHistory<EventHistoryAttachmentPoint>(
-                deviceManager.evHistDevMgrAttachPt, count);
+        return null;
     }
 }

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

@@ -10,17 +10,20 @@ import net.floodlightcontroller.util.EventHistory;
 import org.openflow.protocol.OFMatch;
 import org.restlet.resource.Get;
 import org.restlet.resource.ServerResource;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * @author subrata
  *
  */
 public class EventHistoryPacketInResource extends ServerResource {
-
+    // TODO - Move this to the DeviceManager rest API
+    protected static Logger log = 
+            LoggerFactory.getLogger(EventHistoryPacketInResource.class);
+    
     @Get("json")
     public EventHistory<OFMatch> handleEvHistReq() {
-
-        EventHistory<OFMatch> ofm = null;
         // Get the count (number of latest events requested), zero means all
         String evHistCount = (String)getRequestAttributes().get("count");
         int    count = EventHistory.EV_HISTORY_DEFAULT_SIZE;
@@ -31,12 +34,19 @@ public class EventHistoryPacketInResource extends ServerResource {
             // Invalid input for event count - use default value
         }
 
-        DeviceManagerImpl deviceManager = 
-           (DeviceManagerImpl)getContext().getAttributes().
-               get(IDeviceManagerService.class.getCanonicalName());
-
-        ofm =  new EventHistory<OFMatch>(deviceManager.evHistDevMgrPktIn,count);
-        return ofm;
+        try {
+            DeviceManagerImpl deviceManager = 
+               (DeviceManagerImpl)getContext().getAttributes().
+                   get(IDeviceManagerService.class.getCanonicalName());
+    
+            if (deviceManager != null) {
+                return new EventHistory<OFMatch>(deviceManager.evHistDevMgrPktIn,count);
+            }
+        } catch (ClassCastException e) {
+            log.error(e.toString());
+        }
+        
+        return null;
     }
 
 }

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

@@ -7,12 +7,17 @@ import net.floodlightcontroller.util.EventHistory;
 
 import org.restlet.resource.Get;
 import org.restlet.resource.ServerResource;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * @author subrata
  *
  */
 public class EventHistoryTopologyClusterResource extends ServerResource {
+    // TODO - Move this to the LinkDiscovery rest API
+    protected static Logger log = 
+            LoggerFactory.getLogger(EventHistoryTopologyClusterResource.class);
 
     @Get("json")
     public EventHistory<EventHistoryTopologyCluster> handleEvHistReq() {
@@ -27,11 +32,18 @@ public class EventHistoryTopologyClusterResource extends ServerResource {
             // Invalid input for event count - use default value
         }
 
-        LinkDiscoveryManager topoManager =
-           (LinkDiscoveryManager)getContext().getAttributes().
-               get(ILinkDiscoveryService.class.getCanonicalName());
-
-        return new EventHistory<EventHistoryTopologyCluster>(
-                                topoManager.evHistTopologyCluster, count);
+        try {
+            LinkDiscoveryManager topoManager =
+               (LinkDiscoveryManager)getContext().getAttributes().
+                   get(ILinkDiscoveryService.class.getCanonicalName());
+            if (topoManager != null) {
+                return new EventHistory<EventHistoryTopologyCluster>(
+                        topoManager.evHistTopologyCluster, count);
+            }
+        } catch (ClassCastException e) {
+            log.error(e.toString());
+        }
+        
+        return null;
     }
 }

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

@@ -7,12 +7,17 @@ import net.floodlightcontroller.util.EventHistory;
 
 import org.restlet.resource.Get;
 import org.restlet.resource.ServerResource;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * @author subrata
  *
  */
 public class EventHistoryTopologyLinkResource extends ServerResource {
+    // TODO - Move this to the DeviceManager Rest API
+    protected static Logger log = 
+            LoggerFactory.getLogger(EventHistoryTopologyLinkResource.class);
 
     @Get("json")
     public EventHistory<EventHistoryTopologyLink> handleEvHistReq() {
@@ -27,11 +32,18 @@ public class EventHistoryTopologyLinkResource extends ServerResource {
             // Invalid input for event count - use default value
         }
 
-        LinkDiscoveryManager topoManager =
-           (LinkDiscoveryManager)getContext().getAttributes().
-               get(ILinkDiscoveryService.class.getCanonicalName());
-
-        return new EventHistory<EventHistoryTopologyLink>(
-                                    topoManager.evHistTopologyLink, count);
+        try {
+            LinkDiscoveryManager topoManager =
+               (LinkDiscoveryManager)getContext().getAttributes().
+                   get(ILinkDiscoveryService.class.getCanonicalName());
+            if (topoManager != null) {
+                return new EventHistory<EventHistoryTopologyLink>(
+                                        topoManager.evHistTopologyLink, count);
+            }
+        } catch (ClassCastException e) {
+            log.error(e.toString());
+        }
+        
+        return null;
     }
 }