public static T visit()

in amoro-format-mixed/amoro-mixed-spark/v3.3/amoro-mixed-spark-3.3/src/main/java/org/apache/iceberg/spark/data/AdaptHiveParquetWithSparkSchemaVisitor.java [46:170]
104 lines of code
10 McCabe index (conditional complexity)

  public static <T> T visit(
      DataType sType, Type type, AdaptHiveParquetWithSparkSchemaVisitor<T> visitor) {
    Preconditions.checkArgument(sType != null, "Invalid DataType: null");
    if (type instanceof MessageType) {
      Preconditions.checkArgument(
          sType instanceof StructType, "Invalid struct: %s is not a struct", sType);
      StructType struct = (StructType) sType;
      return visitor.message(
          struct, (MessageType) type, visitFields(struct, type.asGroupType(), visitor));

    } else if (type.isPrimitive()) {
      return visitor.primitive(sType, type.asPrimitiveType());

    } else {
      // if not a primitive, the typeId must be a group
      GroupType group = type.asGroupType();
      OriginalType annotation = group.getOriginalType();
      if (annotation != null) {
        switch (annotation) {
          case LIST:
            Preconditions.checkArgument(
                !group.isRepetition(Repetition.REPEATED),
                "Invalid list: top-level group is repeated: %s",
                group);
            Preconditions.checkArgument(
                group.getFieldCount() == 1,
                "Invalid list: does not contain single repeated field: %s",
                group);

            GroupType repeatedElement = group.getFields().get(0).asGroupType();
            Preconditions.checkArgument(
                repeatedElement.isRepetition(Repetition.REPEATED),
                "Invalid list: inner group is not repeated");
            Preconditions.checkArgument(
                repeatedElement.getFieldCount() <= 1,
                "Invalid list: repeated group is not a single field: %s",
                group);

            Preconditions.checkArgument(
                sType instanceof ArrayType, "Invalid list: %s is not an array", sType);
            ArrayType array = (ArrayType) sType;
            StructField element =
                new StructField(
                    "element", array.elementType(), array.containsNull(), Metadata.empty());

            visitor.fieldNames.push(repeatedElement.getName());
            try {
              T elementResult = null;
              if (repeatedElement.getFieldCount() > 0) {
                elementResult = visitField(element, repeatedElement.getType(0), visitor);
              }

              return visitor.list(array, group, elementResult);

            } finally {
              visitor.fieldNames.pop();
            }

          case MAP:
            Preconditions.checkArgument(
                !group.isRepetition(Repetition.REPEATED),
                "Invalid map: top-level group is repeated: %s",
                group);
            Preconditions.checkArgument(
                group.getFieldCount() == 1,
                "Invalid map: does not contain single repeated field: %s",
                group);

            GroupType repeatedKeyValue = group.getType(0).asGroupType();
            Preconditions.checkArgument(
                repeatedKeyValue.isRepetition(Repetition.REPEATED),
                "Invalid map: inner group is not repeated");
            Preconditions.checkArgument(
                repeatedKeyValue.getFieldCount() <= 2,
                "Invalid map: repeated group does not have 2 fields");

            Preconditions.checkArgument(
                sType instanceof MapType, "Invalid map: %s is not a map", sType);
            MapType map = (MapType) sType;
            StructField keyField = new StructField("key", map.keyType(), false, Metadata.empty());
            StructField valueField =
                new StructField(
                    "value", map.valueType(), map.valueContainsNull(), Metadata.empty());

            visitor.fieldNames.push(repeatedKeyValue.getName());
            try {
              T keyResult = null;
              T valueResult = null;
              switch (repeatedKeyValue.getFieldCount()) {
                case 2:
                  // if there are 2 fields, both key and value are projected
                  keyResult = visitField(keyField, repeatedKeyValue.getType(0), visitor);
                  valueResult = visitField(valueField, repeatedKeyValue.getType(1), visitor);
                  break;
                case 1:
                  // if there is just one, use the name to determine what it is
                  Type keyOrValue = repeatedKeyValue.getType(0);
                  if (keyOrValue.getName().equalsIgnoreCase("key")) {
                    keyResult = visitField(keyField, keyOrValue, visitor);
                    // value result remains null
                  } else {
                    valueResult = visitField(valueField, keyOrValue, visitor);
                    // key result remains null
                  }
                  break;
                default:
                  // both results will remain null
              }

              return visitor.map(map, group, keyResult, valueResult);

            } finally {
              visitor.fieldNames.pop();
            }

          default:
        }
      }

      Preconditions.checkArgument(
          sType instanceof StructType, "Invalid struct: %s is not a struct", sType);
      StructType struct = (StructType) sType;
      return visitor.struct(struct, group, visitFields(struct, group, visitor));
    }
  }