ONOS-4971: Synthetic Link Data -- WIP

- adding CLI commands for dumping Model Cache contents.

Change-Id: I28dfe179835de6cd0c5356faf87af46a239eb772
diff --git a/web/gui/src/main/java/org/onosproject/ui/impl/topo/cli/ListHosts.java b/web/gui/src/main/java/org/onosproject/ui/impl/topo/cli/ListHosts.java
new file mode 100644
index 0000000..9de0159
--- /dev/null
+++ b/web/gui/src/main/java/org/onosproject/ui/impl/topo/cli/ListHosts.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2016-present 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.ui.impl.topo.cli;
+
+import org.apache.karaf.shell.commands.Command;
+import org.onosproject.ui.impl.topo.model.UiSharedTopologyModel;
+
+/**
+ * CLI command to list the UiH0osts stored in the ModelCache.
+ */
+@Command(scope = "onos", name = "ui-cache-hosts",
+        description = "Lists UiHosts in the Model Cache")
+public class ListHosts extends AbstractElementCommand {
+
+    @Override
+    protected void execute() {
+        UiSharedTopologyModel model = get(UiSharedTopologyModel.class);
+        sorted(model.getHosts()).forEach(h -> print("%s", h));
+    }
+}