Displayed message when no resource to display (#197)

* Migrate schemas get all to reactive

* Retrieve all information on get all

* Fix some Sonar

* Fix unit tests

* Display a message when there is no resource to display

Author: Loïc GREFFIER

cli/src/main/java/com/michelin/ns4kafka/cli/DeleteSubcommand.java

@@ -164,7 +164,7 @@ public Integer call() {
                             .findFirst()
                             .orElseThrow();
                     boolean success = resourceService.delete(apiResource, namespace, resource.getMetadata().getName(), dryRun);
-                    if(success) {
+                    if (success) {
                         System.out.println(CommandLine.Help.Ansi.AUTO.string("@|bold,green Success |@") + apiResource.getKind() + "/" + resource.getMetadata().getName() + " (deleted)");
                     }
                     return success;

cli/src/main/java/com/michelin/ns4kafka/cli/GetSubcommand.java

@@ -126,11 +126,16 @@ public Integer call() throws Exception {
             try {
                 // List all resources for given types (k get all, k get topics)
                 Map<ApiResource, List<Resource>> resources = resourceService.listAll(apiResources, namespace);
-                // Display all resources by type
-                resources.entrySet()
-                        .stream()
-                        .filter(kv -> !kv.getValue().isEmpty())
-                        .forEach(kv -> formatService.displayList(kv.getKey().getKind(), kv.getValue(), output));
+
+                if (resources.entrySet().size() == 1 && resources.get(resources.keySet().iterator().next()).isEmpty()) {
+                    System.out.println("No resource to display.");
+                } else {
+                    // Display all resources by type
+                    resources.entrySet()
+                            .stream()
+                            .filter(kv -> !kv.getValue().isEmpty())
+                            .forEach(kv -> formatService.displayList(kv.getKey().getKind(), kv.getValue(), output));
+                }
             } catch (HttpClientResponseException e) {
                 formatService.displayError(e, apiResources.get(0).getKind(), null);
             } catch (Exception e) {