Implement CLI and REST API for Xconnect

Deprecate the old way of configuring Xconnect via network config

Change-Id: I5b9ac7852517c25805bcbfc0e7b3bec3a52eed9f
diff --git a/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/cli/XconnectListCommand.java b/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/cli/XconnectListCommand.java
new file mode 100644
index 0000000..43919c4
--- /dev/null
+++ b/apps/segmentrouting/app/src/main/java/org/onosproject/segmentrouting/cli/XconnectListCommand.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2018-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.segmentrouting.cli;
+
+import org.apache.karaf.shell.commands.Command;
+import org.onosproject.cli.AbstractShellCommand;
+import org.onosproject.segmentrouting.xconnect.api.XconnectService;
+
+/**
+ * Lists Xconnects.
+ */
+@Command(scope = "onos", name = "sr-xconnect", description = "Lists all Xconnects")
+public class XconnectListCommand extends AbstractShellCommand {
+    @Override
+    protected void execute() {
+        XconnectService xconnectService = get(XconnectService.class);
+        xconnectService.getXconnects().forEach(desc -> print("%s", desc));
+    }
+}