[ONOS-5232] bits enum class generation modifications and code refactoring.

Change-Id: I67fb31c586802e9cf682aa6e707475ad8fdc096f
diff --git a/plugin/maven/src/test/resources/ChoiceCaseTranslator.yang b/plugin/maven/src/test/resources/ChoiceCaseTranslator.yang
index 35cbf19..5834795 100644
--- a/plugin/maven/src/test/resources/ChoiceCaseTranslator.yang
+++ b/plugin/maven/src/test/resources/ChoiceCaseTranslator.yang
@@ -2,7 +2,7 @@
     yang-version 1;
     namespace http://huawei.com;
     prefix Ant;
-    notification food {
+    container food {
        choice snack {
            case sports-arena {
                leaf pretzel {
@@ -18,5 +18,25 @@
                }
            }
        }
+       container dinner {
+           leaf cheese {
+               type string;
+           }
+       }
+       choice snack2 {
+                  case sports-arena {
+                      leaf pretzel {
+                          type string;
+                      }
+                      leaf beer {
+                          type string;
+                      }
+                  }
+                  case late-night {
+                      leaf chocolate {
+                          type string;
+                      }
+                  }
+              }
     }
 }