Adding command to list mapping between intent class and compiler

Change-Id: Ie85801b6e924d8bf119d77a7dddd12020b2b1320

+/*
+ * 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.apache.karaf.shell.commands.Command;
+import org.onosproject.cli.AbstractShellCommand;
+import org.onosproject.net.intent.IntentExtensionService;
+
+import java.util.OptionalInt;
+
+/**
+ * Lists the inventory of intents and their states.
+ */
+@Command(scope = "onos", name = "intent-compilers",
+        description = "Lists the mapping from intent type to compiler component")
+public class IntentListCompilers extends AbstractShellCommand {
+
+    @Override
+    protected void execute() {
+        IntentExtensionService service = get(IntentExtensionService.class);
+        OptionalInt length = service.getCompilers().keySet().stream()
+                .mapToInt(s -> s.getName().length())
+                .max();
+        if (length.isPresent()) {
+            service.getCompilers().entrySet().forEach(e -> {
+                print("%-" + length.getAsInt() + "s\t%s",
+                      e.getKey().getName(),
+                      e.getValue().getClass().getName());
+            });
+        } else {
+            print("There are no compilers registered.");
+        }
+
+    }
+}

@@ -218,6 +218,9 @@
             <action class="org.onosproject.cli.net.IntentsListCommand"/>
         </command>
         <command>
+            <action class="org.onosproject.cli.net.IntentListCompilers"/>
+        </command>
+        <command>
             <action class="org.onosproject.cli.net.IntentRemoveCommand"/>
             <completers>
                 <ref component-id="appIdWithIntentNameCompleter"/>