Replacing regular with enhanced switches in GitHubAPIConnector

src/main/java/usi/si/seart/github/GitHubAPIConnector.java

@@ -348,20 +348,12 @@ public FetchCallback.Result doWithRetry(RetryContext context) throws Exception {
             String body = response.body().string();
             JsonElement element = conversionService.convert(body, JsonElement.class);
 
-            switch (series) {
-                case SUCCESSFUL:
-                    return new Result(status, headers, element);
-                case INFORMATIONAL:
-                case REDIRECTION:
-                    return new Result(status, headers, JsonNull.INSTANCE);
-                case CLIENT_ERROR:
-                    return handleClientError(status, headers, element.getAsJsonObject());
-                case SERVER_ERROR:
-                    return handleServerError(status, element.getAsJsonObject());
-                default:
-            }
-
-            throw new IllegalStateException("This line should never be reached");
+            return switch (series) {
+                case SUCCESSFUL -> new Result(status, headers, element);
+                case CLIENT_ERROR -> handleClientError(status, headers, element.getAsJsonObject());
+                case SERVER_ERROR -> handleServerError(status, element.getAsJsonObject());
+                case INFORMATIONAL, REDIRECTION -> new Result(status, headers, JsonNull.INSTANCE);
+            };
         }
 
         private FetchCallback.Result handleServerError(HttpStatus status, JsonObject json) {
@@ -375,19 +367,15 @@ private FetchCallback.Result handleClientError(
         ) throws InterruptedException {
             ErrorResponse errorResponse = conversionService.convert(json, ErrorResponse.class);
             switch (status) {
-                case UNAUTHORIZED:
-                    /*
-                     * Here we should not call `replaceTokenIfExpired()`
-                     * since it would lead to an infinite loop,
-                     * because we are checking the Rate Limit API
-                     * with the very same unauthorized token.
-                     */
-                    gitHubTokenManager.replaceToken();
-                    break;
-                case TOO_MANY_REQUESTS:
-                    TimeUnit.MINUTES.sleep(5);
-                    break;
-                case FORBIDDEN:
+                /*
+                 * Here we should not call `replaceTokenIfExpired()`
+                 * since it would lead to an infinite loop,
+                 * because we are checking the Rate Limit API
+                 * with the very same unauthorized token.
+                 */
+                case UNAUTHORIZED -> gitHubTokenManager.replaceToken();
+                case TOO_MANY_REQUESTS -> TimeUnit.MINUTES.sleep(5);
+                case FORBIDDEN -> {
                     /*
                      * Response status code 403, two possibilities:
                      * (1) The rate limit for the current token is exceeded
@@ -404,16 +392,17 @@ private FetchCallback.Result handleClientError(
                         throw new IllegalStateException(message);
                     } else if (remaining == 0) {
                         gitHubTokenManager.replaceTokenIfExpired();
-                        break;
                     } else {
                         /*
                          * Case (2) encountered, so we propagate error upwards
                          * @see fetchLastPageNumberFromHeader
                          */
                         return new Result(status, headers, json);
                     }
-                default:
+                }
+                default -> {
                     // TODO: 30.07.23 Add any other special logic here
+                }
             }
             throw new HttpClientErrorException(status, errorResponse.getMessage());
         }