[ONOS-4015] Implement Region administration CLI

- Implement region add/update/remove CLI
- Implement devices add/remove CLI

Change-Id: I38b40b24df7f864b0725104f63347081257743ac
diff --git a/cli/src/main/java/org/onosproject/cli/net/RegionIdCompleter.java b/cli/src/main/java/org/onosproject/cli/net/RegionIdCompleter.java
new file mode 100644
index 0000000..60cacc9
--- /dev/null
+++ b/cli/src/main/java/org/onosproject/cli/net/RegionIdCompleter.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2016 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.cli.net;
+
+import org.onosproject.cli.AbstractChoicesCompleter;
+import org.onosproject.cli.AbstractShellCommand;
+import org.onosproject.net.region.RegionService;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * Region ID completer.
+ */
+public class RegionIdCompleter extends AbstractChoicesCompleter {
+    @Override
+    protected List<String> choices() {
+        RegionService service = AbstractShellCommand.get(RegionService.class);
+        return service.getRegions()
+                .stream()
+                .map(r -> r.id().toString())
+                .collect(Collectors.toList());
+    }
+}