[ONOS-3203] End-to-end demo of Fault Management via SNMP.

This adds SNMP device-discovery, and a Fault Management app which makes alarms available to users via REST/GUI/CLI interfaces.
There is still code cleanup that could be done, but aim of this commit is an end-to-end proof of concept.

To demonstrate :

1) /opt/onos/bin/onos-service
onos> app activate org.onosproject.snmp
onos> app activate org.onosproject.faultmanagement

2) SNMP devices are seeded via config file. The default seed file contains connection details for devices (SNMP agents) available via internet  e.g. demo.snmplabs.com
cp /opt/onos/apache-karaf-3.0.3/etc/samples/org.onosproject.provider.snmp.device.impl.SnmpDeviceProvider.cfg   /opt/onos/apache-karaf-3.0.3/etc/

3) ONOS will poll these SNMP devices and store their alarms.

4) You can now manipulate the alarms via REST  e.g. http://<onos>:8181/onos/v1/fm/alarms , via CLI  via various "alarm-*” commands or in UI with an Alarms Overlay.

More info at https://wiki.onosproject.org/display/ONOS/Fault+Management

15/Dec/15: Updated regarding review comments from Thomas Vachuska.
17/Dec/15: Updated coreService.registerApplication(name) as per https://gerrit.onosproject.org/#/c/6878/

Change-Id: I886f8511f178dc4600ab96e5ff10cc90329cabec
diff --git a/apps/faultmanagement/fmgui/src/main/java/org/onosproject/faultmanagement/alarms/gui/AlarmTopovMessageHandler.java b/apps/faultmanagement/fmgui/src/main/java/org/onosproject/faultmanagement/alarms/gui/AlarmTopovMessageHandler.java
new file mode 100644
index 0000000..adeb9d5
--- /dev/null
+++ b/apps/faultmanagement/fmgui/src/main/java/org/onosproject/faultmanagement/alarms/gui/AlarmTopovMessageHandler.java
@@ -0,0 +1,224 @@
+/*
+ * Copyright 2014,2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.faultmanagement.alarms.gui;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableSet;
+import org.onlab.osgi.ServiceDirectory;
+import org.onosproject.net.Device;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Element;
+import org.onosproject.net.HostId;
+import org.onosproject.net.device.DeviceService;
+import org.onosproject.net.host.HostService;
+import org.onosproject.ui.RequestHandler;
+import org.onosproject.ui.UiConnection;
+import org.onosproject.ui.UiMessageHandler;
+import org.onosproject.ui.topo.DeviceHighlight;
+import org.onosproject.ui.topo.Highlights;
+import org.onosproject.ui.topo.NodeBadge;
+import org.onosproject.ui.topo.NodeBadge.Status;
+import org.onosproject.ui.topo.TopoJson;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collection;
+import java.util.Set;
+import org.onosproject.incubator.net.faultmanagement.alarm.Alarm;
+import org.onosproject.incubator.net.faultmanagement.alarm.AlarmService;
+
+/**
+ * Skeletal ONOS UI Topology-Overlay message handler.
+ */
+public class AlarmTopovMessageHandler extends UiMessageHandler {
+
+    private static final String ALARM_TOPOV_DISPLAY_START = "alarmTopovDisplayStart";
+    private static final String ALARM_TOPOV_DISPLAY_UPDATE = "alarmTopovDisplayUpdate";
+    private static final String ALARM_TOPOV_DISPLAY_STOP = "alarmTopovDisplayStop";
+
+    private static final String ID = "id";
+    private static final String MODE = "mode";
+
+    private enum Mode {
+
+        IDLE, MOUSE
+    }
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private DeviceService deviceService;
+    private HostService hostService;
+    private AlarmService alarmService;
+
+    private Mode currentMode = Mode.IDLE;
+    private Element elementOfNote;
+
+    // ===============-=-=-=-=-=-======================-=-=-=-=-=-=-================================
+    @Override
+    public void init(UiConnection connection, ServiceDirectory directory) {
+        super.init(connection, directory);
+        deviceService = directory.get(DeviceService.class);
+        hostService = directory.get(HostService.class);
+        alarmService = directory.get(AlarmService.class);
+    }
+
+    @Override
+    protected Collection<RequestHandler> createRequestHandlers() {
+        return ImmutableSet.of(
+                new DisplayStartHandler(),
+                new DisplayUpdateHandler(),
+                new DisplayStopHandler()
+        );
+    }
+
+    // === -------------------------
+    // === Handler classes
+    private final class DisplayStartHandler extends RequestHandler {
+
+        public DisplayStartHandler() {
+            super(ALARM_TOPOV_DISPLAY_START);
+        }
+
+        @Override
+        public void process(long sid, ObjectNode payload) {
+            String mode = string(payload, MODE);
+
+            log.debug("Start Display: mode [{}]", mode);
+            clearState();
+            clearForMode();
+
+            switch (mode) {
+                case "mouse":
+                    currentMode = Mode.MOUSE;
+
+                    sendMouseData();
+                    break;
+
+                default:
+                    currentMode = Mode.IDLE;
+
+                    break;
+            }
+        }
+    }
+
+    private final class DisplayUpdateHandler extends RequestHandler {
+
+        public DisplayUpdateHandler() {
+            super(ALARM_TOPOV_DISPLAY_UPDATE);
+        }
+
+        @Override
+        public void process(long sid, ObjectNode payload) {
+            String id = string(payload, ID);
+            log.debug("Update Display: id [{}]", id);
+            if (!Strings.isNullOrEmpty(id)) {
+                updateForMode(id);
+            } else {
+                clearForMode();
+            }
+        }
+    }
+
+    private final class DisplayStopHandler extends RequestHandler {
+
+        public DisplayStopHandler() {
+            super(ALARM_TOPOV_DISPLAY_STOP);
+        }
+
+        @Override
+        public void process(long sid, ObjectNode payload) {
+            log.debug("Stop Display");
+            clearState();
+            clearForMode();
+        }
+    }
+
+    // === ------------
+    private void clearState() {
+        currentMode = Mode.IDLE;
+        elementOfNote = null;
+    }
+
+    private void updateForMode(String id) {
+        log.debug("host service: {}", hostService);
+        log.debug("device service: {}", deviceService);
+
+        try {
+            HostId hid = HostId.hostId(id);
+            log.debug("host id {}", hid);
+            elementOfNote = hostService.getHost(hid);
+            log.debug("host element {}", elementOfNote);
+
+        } catch (RuntimeException e) {
+            try {
+                DeviceId did = DeviceId.deviceId(id);
+                log.debug("device id {}", did);
+                elementOfNote = deviceService.getDevice(did);
+                log.debug("device element {}", elementOfNote);
+
+            } catch (RuntimeException e2) {
+                log.debug("Unable to process ID [{}]", id);
+                elementOfNote = null;
+            }
+        }
+
+        switch (currentMode) {
+            case MOUSE:
+                sendMouseData();
+                break;
+
+            default:
+                break;
+        }
+
+    }
+
+    private void clearForMode() {
+        sendHighlights(new Highlights());
+    }
+
+    private void sendHighlights(Highlights highlights) {
+        sendMessage(TopoJson.highlightsMessage(highlights));
+    }
+
+    private void sendMouseData() {
+        if (elementOfNote != null && elementOfNote instanceof Device) {
+            DeviceId devId = (DeviceId) elementOfNote.id();
+            Set<Alarm> alarmsOnDevice = alarmService.getAlarms(devId);
+            Highlights highlights = new Highlights();
+
+            addDeviceBadge(highlights, devId, alarmsOnDevice.size());
+            sendHighlights(highlights);
+        }
+        // Note: could also process Host, if available
+    }
+
+    private void addDeviceBadge(Highlights h, DeviceId devId, int n) {
+        DeviceHighlight dh = new DeviceHighlight(devId.toString());
+        dh.setBadge(createBadge(n));
+        h.add(dh);
+    }
+
+    private NodeBadge createBadge(int n) {
+        Status status = n > 0 ? Status.ERROR : Status.INFO;
+        String noun = n > 0 ? "(Alarmed)" : "(Normal)";
+        String msg = "Alarms: " + n + " " + noun;
+        return NodeBadge.number(status, n, msg);
+    }
+
+}