[ONOS-7054] Implement prototype of ISSU protocol

Change-Id: Id543c0de9c97b68f977c824cbc987b35d81beb2d
diff --git a/cli/src/main/java/org/onosproject/cli/IssuCommand.java b/cli/src/main/java/org/onosproject/cli/IssuCommand.java
new file mode 100644
index 0000000..1f0cb36
--- /dev/null
+++ b/cli/src/main/java/org/onosproject/cli/IssuCommand.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+ *
+ * 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.cli;
+
+import org.apache.karaf.shell.commands.Argument;
+import org.apache.karaf.shell.commands.Command;
+import org.onosproject.upgrade.UpgradeAdminService;
+import org.onosproject.upgrade.UpgradeService;
+
+/**
+ * Commands for managing upgrades.
+ */
+@Command(scope = "onos", name = "issu",
+        description = "Manages upgrades")
+public class IssuCommand extends AbstractShellCommand {
+
+    static final String INIT = "init";
+    static final String UPGRADE = "upgrade";
+    static final String COMMIT = "commit";
+    static final String ROLLBACK = "rollback";
+    static final String RESET = "reset";
+    static final String STATUS = "status";
+    static final String VERSION = "version";
+
+    @Argument(index = 0, name = "command",
+            description = "Command name (init|upgrade|commit|rollback|status|version)",
+            required = false, multiValued = false)
+    String command = null;
+
+    @Override
+    protected void execute() {
+        UpgradeService upgradeService = get(UpgradeService.class);
+        UpgradeAdminService upgradeAdminService = get(UpgradeAdminService.class);
+        if (command == null) {
+            print("source=%s, target=%s, status=%s, upgraded=%b, active=%b",
+                    upgradeService.getState().source(),
+                    upgradeService.getState().target(),
+                    upgradeService.getState().status(),
+                    upgradeService.isLocalUpgraded(),
+                    upgradeService.isLocalActive());
+        } else if (command.equals(INIT)) {
+            upgradeAdminService.initialize();
+            print("Initialized");
+        } else if (command.equals(UPGRADE)) {
+            upgradeAdminService.upgrade();
+            print("Upgraded");
+        } else if (command.equals(COMMIT)) {
+            upgradeAdminService.commit();
+            print("Committed version %s", upgradeService.getVersion());
+        } else if (command.equals(ROLLBACK)) {
+            upgradeAdminService.rollback();
+            print("Rolled back to version %s", upgradeService.getVersion());
+        } else if (command.equals(RESET)) {
+            upgradeAdminService.reset();
+            print("Reset version %s", upgradeService.getVersion());
+        } else if (command.equals(STATUS)) {
+            print("%s", upgradeService.getState().status());
+        } else if (command.equals(VERSION)) {
+            print("%s", upgradeService.getVersion());
+        } else {
+            print("Unsupported command: %s", command);
+        }
+    }
+
+}