Refactor k8s-node and k8s-networking command line interfaces

Change-Id: I1eb20ccea5238893a1c58e7faeb4c3a06accd2a9
diff --git a/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/util/K8sNetworkingUtil.java b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/util/K8sNetworkingUtil.java
index 7d20b65..17240fb 100644
--- a/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/util/K8sNetworkingUtil.java
+++ b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/util/K8sNetworkingUtil.java
@@ -55,6 +55,7 @@
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
@@ -546,6 +547,22 @@
         }
     }
 
+    /**
+     * Generates string format based on the given string length list.
+     *
+     * @param stringLengths a list of string lengths
+     * @return string format (e.g., %-28s%-15s%-24s%-20s%-15s)
+     */
+    public static String genFormatString(List<Integer> stringLengths) {
+        StringBuilder fsb = new StringBuilder();
+        stringLengths.forEach(length -> {
+            fsb.append("%-");
+            fsb.append(length);
+            fsb.append("s");
+        });
+        return fsb.toString();
+    }
+
     private static int binLower(String binStr, int bits) {
         StringBuilder outBin = new StringBuilder(
                 binStr.substring(MASK_BEGIN_IDX, MASK_MAX_IDX - bits));