Adding some flesh to the simple device manager.
diff --git a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java
index ce7c6c4..7038284 100644
--- a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java
+++ b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceManager.java
@@ -4,12 +4,20 @@
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Service;
+import org.onlab.onos.event.AbstractListenerManager;
+import org.onlab.onos.event.EventDispatchService;
+import org.onlab.onos.net.Device;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.MastershipRole;
+import org.onlab.onos.net.Port;
+import org.onlab.onos.net.PortNumber;
 import org.onlab.onos.net.device.DeviceDescription;
+import org.onlab.onos.net.device.DeviceEvent;
+import org.onlab.onos.net.device.DeviceListener;
 import org.onlab.onos.net.device.DeviceProvider;
 import org.onlab.onos.net.device.DeviceProviderBroker;
 import org.onlab.onos.net.device.DeviceProviderService;
+import org.onlab.onos.net.device.DeviceService;
 import org.onlab.onos.net.device.PortDescription;
 import org.onlab.onos.net.provider.AbstractProviderBroker;
 import org.onlab.onos.net.provider.AbstractProviderService;
@@ -18,47 +26,86 @@
 
 import java.util.List;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 /**
  * Provides basic implementation of the device SB & NB APIs.
  */
 @Component(immediate = true)
 @Service
-public class SimpleDeviceManager implements DeviceProviderBroker {
+public class SimpleDeviceManager
+        extends AbstractProviderBroker<DeviceProvider, DeviceProviderService>
+        implements DeviceService, DeviceProviderBroker {
+
+    public static final String DEVICE_ID_NULL = "Device ID cannot be null";
+    public static final String PORT_NUMBER_NULL = "Port number cannot be null";
+    public static final String DEVICE_DESCRIPTION_NULL = "Device description cannot be null";
+    public static final String PORT_DESCRIPTION_NULL = "Port description cannot be null";
 
     private Logger log = LoggerFactory.getLogger(SimpleDeviceManager.class);
 
-    private final DeviceProviderBroker broker = new InternalBroker();
+    private final AbstractListenerManager<DeviceEvent, DeviceListener>
+            listenerManager = new AbstractListenerManager<>();
+
+    private EventDispatchService eventDispatcher;
+
+    private final DeviceStore store = new DeviceStore();
 
     @Activate
     public void activate() {
+//        eventDispatcher.addSink(DeviceEvent.class, listenerManager);
         log.info("Started");
     }
 
     @Deactivate
     public void deactivate() {
+//        eventDispatcher.removeSink(DeviceEvent.class);
         log.info("Stopped");
     }
 
     @Override
-    public DeviceProviderService register(DeviceProvider provider) {
-        log.info("Registering provider {}", provider.id());
-        return broker.register(provider);
+    public MastershipRole getRole(DeviceId deviceId) {
+        checkNotNull(deviceId, DEVICE_ID_NULL);
+        return null;
     }
 
     @Override
-    public void unregister(DeviceProvider provider) {
-        log.info("Unregistering provider {}", provider.id());
-        broker.unregister(provider);
+    public Iterable<Device> getDevices() {
+        return null;
     }
 
-    // Internal delegate for tracking various providers and issuing them a
-    // personalized provider service.
-    private class InternalBroker extends AbstractProviderBroker<DeviceProvider, DeviceProviderService>
-            implements DeviceProviderBroker {
-        @Override
-        protected DeviceProviderService createProviderService(DeviceProvider provider) {
-            return new InternalDeviceProviderService(provider);
-        }
+    @Override
+    public Device getDevice(DeviceId deviceId) {
+        checkNotNull(deviceId, DEVICE_ID_NULL);
+        return null;
+    }
+
+    @Override
+    public List<Port> getPorts(DeviceId deviceId) {
+        checkNotNull(deviceId, DEVICE_ID_NULL);
+        return null;
+    }
+
+    @Override
+    public Port getPort(DeviceId deviceId, PortNumber portNumber) {
+        checkNotNull(deviceId, DEVICE_ID_NULL);
+        checkNotNull(portNumber, PORT_NUMBER_NULL);
+        return null;
+    }
+
+    @Override
+    public void addListener(DeviceListener listener) {
+        listenerManager.addListener(listener);
+    }
+
+    @Override
+    public void removeListener(DeviceListener listener) {
+        listenerManager.removeListener(listener);
+    }
+
+    @Override
+    protected DeviceProviderService createProviderService(DeviceProvider provider) {
+        return new InternalDeviceProviderService(provider);
     }
 
     // Personalized device provider service issued to the supplied provider.
@@ -71,26 +118,49 @@
 
         @Override
         public MastershipRole deviceConnected(DeviceId deviceId, DeviceDescription deviceDescription) {
+            checkNotNull(deviceId, DEVICE_ID_NULL);
+            checkNotNull(deviceDescription, DEVICE_DESCRIPTION_NULL);
             log.info("Device {} connected: {}", deviceId, deviceDescription);
+            DeviceEvent event = store.createOrUpdateDevice(deviceId, deviceDescription);
+            post(event);
             return MastershipRole.MASTER;
         }
 
         @Override
         public void deviceDisconnected(DeviceId deviceId) {
+            checkNotNull(deviceId, DEVICE_ID_NULL);
             log.info("Device {} disconnected", deviceId);
-
+            DeviceEvent event = store.removeDevice(deviceId);
+            post(event);
         }
 
         @Override
-        public void updatePorts(DeviceId deviceId, List<PortDescription> ports) {
+        public void updatePorts(DeviceId deviceId, List<PortDescription> portDescriptions) {
+            checkNotNull(deviceId, DEVICE_ID_NULL);
+            checkNotNull(portDescriptions, "Port descriptions list cannot be null");
             // FIXME: fix the interface to accept DeviceId separately
-            log.info("Device {} ports updated: {}", ports);
-
+            log.info("Device {} ports updated: {}", portDescriptions);
+            List<DeviceEvent> events = store.updatePorts(deviceId, portDescriptions);
+            for (DeviceEvent event : events) {
+                post(event);
+            }
         }
 
         @Override
-        public void portStatusChanged(DeviceId deviceId, PortDescription port) {
-            log.info("Device {} port status changed: {}", deviceId, port);
+        public void portStatusChanged(DeviceId deviceId, PortDescription portDescription) {
+            checkNotNull(deviceId, DEVICE_ID_NULL);
+            checkNotNull(portDescription, PORT_DESCRIPTION_NULL);
+            log.info("Device {} port status changed: {}", deviceId, portDescription);
+            DeviceEvent event = store.updatePortStatus(deviceId, portDescription);
+            post(event);
         }
     }
+
+    // Posts the specified event to a local event dispatcher
+    private void post(DeviceEvent event) {
+        if (event != null && eventDispatcher != null) {
+            eventDispatcher.post(event);
+        }
+    }
+
 }