BE: Clean some Sonar issues

api/pom.xml

@@ -329,7 +329,7 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-surefire-plugin</artifactId>
                 <configuration>
-                    <argLine>@{argLine} --illegal-access=permit</argLine>
+                    <argLine>@{argLine}</argLine>
                 </configuration>
             </plugin>
             <plugin>

api/src/main/java/io/kafbat/ui/exception/CelException.java

@@ -1,7 +1,10 @@
 package io.kafbat.ui.exception;
 
+import lombok.Getter;
+
+@Getter
 public class CelException extends CustomBaseException {
-  private String celOriginalExpression;
+  private final String celOriginalExpression;
 
   public CelException(String celOriginalExpression, String errorMessage) {
     super("CEL error. Original expression: %s. Error message: %s".formatted(celOriginalExpression, errorMessage));

api/src/main/java/io/kafbat/ui/exception/GlobalErrorWebExceptionHandler.java

@@ -54,18 +54,18 @@ private Mono<ServerResponse> renderErrorResponse(ServerRequest request) {
     Throwable throwable = getError(request);
 
     // validation and params binding errors
-    if (throwable instanceof WebExchangeBindException) {
-      return render((WebExchangeBindException) throwable, request);
+    if (throwable instanceof WebExchangeBindException webExchangeBindException) {
+      return render(webExchangeBindException, request);
     }
 
     // requests mapping & access errors
-    if (throwable instanceof ResponseStatusException) {
-      return render((ResponseStatusException) throwable, request);
+    if (throwable instanceof ResponseStatusException responseStatusException) {
+      return render(responseStatusException, request);
     }
 
     // custom exceptions
-    if (throwable instanceof CustomBaseException) {
-      return render((CustomBaseException) throwable, request);
+    if (throwable instanceof CustomBaseException customBaseException) {
+      return render(customBaseException, request);
     }
 
     return renderDefault(throwable, request);
@@ -151,9 +151,7 @@ private String requestId(ServerRequest request) {
   }
 
   private Consumer<HttpHeaders> headers(ServerRequest request) {
-    return (HttpHeaders headers) -> {
-      CorsGlobalConfiguration.fillCorsHeader(headers, request.exchange().getRequest());
-    };
+    return (HttpHeaders headers) -> CorsGlobalConfiguration.fillCorsHeader(headers, request.exchange().getRequest());
   }
 
   private BigDecimal currentTimestamp() {

api/src/main/java/io/kafbat/ui/model/rbac/provider/Provider.java

@@ -21,11 +21,11 @@ public static Provider fromString(String name) {
   }
 
   public static class Name {
-    public static String GOOGLE = "google";
-    public static String GITHUB = "github";
-    public static String COGNITO = "cognito";
+    public static final String GOOGLE = "google";
+    public static final String GITHUB = "github";
+    public static final String COGNITO = "cognito";
 
-    public static String OAUTH = "oauth";
+    public static final String OAUTH = "oauth";
   }
 
 }

api/src/main/java/io/kafbat/ui/serdes/builtin/Base64Serde.java

@@ -40,7 +40,7 @@ public Serde.Serializer serializer(String topic, Serde.Target type) {
     return inputString -> {
       inputString = inputString.trim();
       // it is actually a hack to provide ability to sent empty array as a key/value
-      if (inputString.length() == 0) {
+      if (inputString.isEmpty()) {
         return new byte[] {};
       }
       return decoder.decode(inputString);

api/src/main/java/io/kafbat/ui/serdes/builtin/HexSerde.java

@@ -62,7 +62,7 @@ public Serializer serializer(String topic, Target type) {
     return input -> {
       input = input.trim();
       // it is a hack to provide ability to sent empty array as a key/value
-      if (input.length() == 0) {
+      if (input.isEmpty()) {
         return new byte[] {};
       }
       return HexFormat.of().parseHex(prepareInputForParse(input));

api/src/main/java/io/kafbat/ui/serdes/builtin/ProtobufFileSerde.java

@@ -383,9 +383,9 @@ private ProtoFile loadKnownProtoFile(String path, Descriptors.FileDescriptor fil
       String protoFileString = null;
       // know type file contains either message or enum
       if (!fileDescriptor.getMessageTypes().isEmpty()) {
-        protoFileString = new ProtobufSchema(fileDescriptor.getMessageTypes().get(0)).canonicalString();
+        protoFileString = new ProtobufSchema(fileDescriptor.getMessageTypes().getFirst()).canonicalString();
       } else if (!fileDescriptor.getEnumTypes().isEmpty()) {
-        protoFileString = new ProtobufSchema(fileDescriptor.getEnumTypes().get(0)).canonicalString();
+        protoFileString = new ProtobufSchema(fileDescriptor.getEnumTypes().getFirst()).canonicalString();
       } else {
         throw new IllegalStateException();
       }

api/src/main/java/io/kafbat/ui/service/audit/AuditRecord.java

@@ -53,14 +53,12 @@ static OperationResult successful() {
     }
 
     static OperationResult error(Throwable th) {
-      OperationError err = OperationError.UNRECOGNIZED_ERROR;
-      if (th instanceof AccessDeniedException) {
-        err = OperationError.ACCESS_DENIED;
-      } else if (th instanceof ValidationException) {
-        err = OperationError.VALIDATION_ERROR;
-      } else if (th instanceof CustomBaseException) {
-        err = OperationError.EXECUTION_ERROR;
-      }
+      OperationError err = switch (th) {
+        case AccessDeniedException ignored -> OperationError.ACCESS_DENIED;
+        case ValidationException ignored -> OperationError.VALIDATION_ERROR;
+        case CustomBaseException ignored -> OperationError.EXECUTION_ERROR;
+        case null, default -> OperationError.UNRECOGNIZED_ERROR;
+      };
       return new OperationResult(false, err);
     }
 

api/src/main/java/io/kafbat/ui/service/integration/odd/ConnectorInfo.java

@@ -5,7 +5,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import java.util.function.Function;
+import java.util.function.UnaryOperator;
 import java.util.stream.Stream;
 import javax.annotation.Nullable;
 import org.apache.commons.collections.CollectionUtils;
@@ -22,7 +22,7 @@ static ConnectorInfo extract(String className,
                                ConnectorTypeDTO type,
                                Map<String, Object> config,
                                List<String> topicsFromApi, // can be empty for old Connect API versions
-                               Function<String, String> topicOddrnBuilder) {
+                               UnaryOperator<String> topicOddrnBuilder) {
     return switch (className) {
       case "org.apache.kafka.connect.file.FileStreamSinkConnector",
           "org.apache.kafka.connect.file.FileStreamSourceConnector",
@@ -43,7 +43,7 @@ static ConnectorInfo extract(String className,
   private static ConnectorInfo extractFileIoConnector(ConnectorTypeDTO type,
                                                       List<String> topics,
                                                       Map<String, Object> config,
-                                                      Function<String, String> topicOddrnBuilder) {
+                                                      UnaryOperator<String> topicOddrnBuilder) {
     return new ConnectorInfo(
         extractInputs(type, topics, config, topicOddrnBuilder),
         extractOutputs(type, topics, config, topicOddrnBuilder)
@@ -53,7 +53,7 @@ private static ConnectorInfo extractFileIoConnector(ConnectorTypeDTO type,
   private static ConnectorInfo extractJdbcSink(ConnectorTypeDTO type,
                                                List<String> topics,
                                                Map<String, Object> config,
-                                               Function<String, String> topicOddrnBuilder) {
+                                               UnaryOperator<String> topicOddrnBuilder) {
     String tableNameFormat = (String) config.getOrDefault("table.name.format", "${topic}");
     List<String> targetTables = extractTopicNamesBestEffort(topics, config)
         .map(topic -> tableNameFormat.replace("${kafka}", topic))
@@ -106,7 +106,7 @@ private static ConnectorInfo extractDebeziumMysql(Map<String, Object> config) {
   private static ConnectorInfo extractS3Sink(ConnectorTypeDTO type,
                                              List<String> topics,
                                              Map<String, Object> config,
-                                             Function<String, String> topicOrrdnBuilder) {
+                                             UnaryOperator<String> topicOrrdnBuilder) {
     String bucketName = (String) config.get("s3.bucket.name");
     String topicsDir = (String) config.getOrDefault("topics.dir", "topics");
     String directoryDelim = (String) config.getOrDefault("directory.delim", "/");
@@ -122,7 +122,7 @@ private static ConnectorInfo extractS3Sink(ConnectorTypeDTO type,
   private static List<String> extractInputs(ConnectorTypeDTO type,
                                             List<String> topicsFromApi,
                                             Map<String, Object> config,
-                                            Function<String, String> topicOrrdnBuilder) {
+                                            UnaryOperator<String> topicOrrdnBuilder) {
     return type == ConnectorTypeDTO.SINK
         ? extractTopicsOddrns(config, topicsFromApi, topicOrrdnBuilder)
         : List.of();
@@ -131,7 +131,7 @@ private static List<String> extractInputs(ConnectorTypeDTO type,
   private static List<String> extractOutputs(ConnectorTypeDTO type,
                                              List<String> topicsFromApi,
                                              Map<String, Object> config,
-                                             Function<String, String> topicOrrdnBuilder) {
+                                             UnaryOperator<String> topicOrrdnBuilder) {
     return type == ConnectorTypeDTO.SOURCE
         ? extractTopicsOddrns(config, topicsFromApi, topicOrrdnBuilder)
         : List.of();
@@ -158,7 +158,7 @@ private static Stream<String> extractTopicNamesBestEffort(
 
   private static List<String> extractTopicsOddrns(Map<String, Object> config,
                                                   List<String> topicsFromApi,
-                                                  Function<String, String> topicOrrdnBuilder) {
+                                                  UnaryOperator<String> topicOrrdnBuilder) {
     return extractTopicNamesBestEffort(topicsFromApi, config)
         .map(topicOrrdnBuilder)
         .toList();

api/src/main/java/io/kafbat/ui/service/integration/odd/schema/JsonSchemaExtractor.java

@@ -286,25 +286,17 @@ private static DataSetField createDataSetField(Schema schema,
   }
 
   private static DataSetFieldType.TypeEnum mapType(Schema type) {
-    if (type instanceof NumberSchema) {
-      return DataSetFieldType.TypeEnum.NUMBER;
-    }
-    if (type instanceof StringSchema) {
-      return DataSetFieldType.TypeEnum.STRING;
-    }
-    if (type instanceof BooleanSchema || type instanceof TrueSchema || type instanceof FalseSchema) {
-      return DataSetFieldType.TypeEnum.BOOLEAN;
-    }
-    if (type instanceof ObjectSchema) {
-      return DataSetFieldType.TypeEnum.STRUCT;
-    }
-    if (type instanceof ReferenceSchema s) {
-      return mapType(s.getReferredSchema());
-    }
-    if (type instanceof CombinedSchema) {
-      return DataSetFieldType.TypeEnum.UNION;
-    }
-    return DataSetFieldType.TypeEnum.UNKNOWN;
+    return switch (type) {
+      case NumberSchema ignored -> DataSetFieldType.TypeEnum.NUMBER;
+      case StringSchema ignored -> DataSetFieldType.TypeEnum.STRING;
+      case BooleanSchema ignored -> DataSetFieldType.TypeEnum.BOOLEAN;
+      case TrueSchema ignored -> DataSetFieldType.TypeEnum.BOOLEAN;
+      case FalseSchema ignored -> DataSetFieldType.TypeEnum.BOOLEAN;
+      case ObjectSchema ignored -> DataSetFieldType.TypeEnum.STRUCT;
+      case ReferenceSchema referenceSchema -> mapType(referenceSchema.getReferredSchema());
+      case CombinedSchema ignored -> DataSetFieldType.TypeEnum.UNION;
+      default -> DataSetFieldType.TypeEnum.UNKNOWN;
+    };
   }
 
 }

api/src/main/java/io/kafbat/ui/service/ksql/KsqlGrammar.java

@@ -74,13 +74,10 @@ public static CaseInsensitiveStream from(CharStream stream) {
         @Override
         public int LA(final int i) {
           final int result = stream.LA(i);
-          switch (result) {
-            case 0:
-            case IntStream.EOF:
-              return result;
-            default:
-              return Character.toUpperCase(result);
-          }
+          return switch (result) {
+            case 0, IntStream.EOF -> result;
+            default -> Character.toUpperCase(result);
+          };
         }
       };
     }

api/src/main/java/io/kafbat/ui/service/metrics/JmxMetricsFormatter.java

@@ -51,10 +51,10 @@ private static Optional<BigDecimal> convertNumericValue(Object value) {
       return Optional.empty();
     }
     try {
-      if (value instanceof Long) {
-        return Optional.of(new BigDecimal((Long) value));
-      } else if (value instanceof Integer) {
-        return Optional.of(new BigDecimal((Integer) value));
+      if (value instanceof Long longValue) {
+        return Optional.of(new BigDecimal(longValue));
+      } else if (value instanceof Integer integerValue) {
+        return Optional.of(new BigDecimal(integerValue));
       }
       return Optional.of(new BigDecimal(value.toString()));
     } catch (NumberFormatException nfe) {

api/src/main/java/io/kafbat/ui/util/jsonschema/AvroJsonSchemaConverter.java

@@ -153,12 +153,11 @@ private JsonType convertType(Schema schema) {
       case INT, LONG -> new SimpleJsonType(JsonType.Type.INTEGER);
       case MAP, RECORD -> new SimpleJsonType(JsonType.Type.OBJECT);
       case ENUM -> new EnumJsonType(schema.getEnumSymbols());
-      case BYTES, STRING -> new SimpleJsonType(JsonType.Type.STRING);
       case NULL -> new SimpleJsonType(JsonType.Type.NULL);
       case ARRAY -> new SimpleJsonType(JsonType.Type.ARRAY);
       case FIXED, FLOAT, DOUBLE -> new SimpleJsonType(JsonType.Type.NUMBER);
       case BOOLEAN -> new SimpleJsonType(JsonType.Type.BOOLEAN);
-      default -> new SimpleJsonType(JsonType.Type.STRING);
+      default -> new SimpleJsonType(JsonType.Type.STRING); // BYTES, STRING and the remaining possibilities
     };
   }
 }