private List getInternalPartitionFields()

in xtable-core/src/main/java/org/apache/xtable/delta/DeltaPartitionExtractor.java [119:180]
56 lines of code
10 McCabe index (conditional complexity)

  private List<InternalPartitionField> getInternalPartitionFields(
      StructType partitionSchema, InternalSchema internalSchema) {
    PeekingIterator<StructField> itr =
        Iterators.peekingIterator(Arrays.stream(partitionSchema.fields()).iterator());
    List<InternalPartitionField> partitionFields = new ArrayList<>(partitionSchema.fields().length);
    while (itr.hasNext()) {
      StructField currPartitionField = itr.peek();
      if (!currPartitionField.metadata().contains(DELTA_GENERATION_EXPRESSION)) {
        partitionFields.add(
            InternalPartitionField.builder()
                .sourceField(
                    SchemaFieldFinder.getInstance()
                        .findFieldByPath(internalSchema, currPartitionField.name()))
                .transformType(PartitionTransformType.VALUE)
                .build());
        itr.next(); // consume the field.
      } else {
        // Partition contains generated expression.
        // if it starts with year we should consume until we hit field with no generated expression
        // or we hit a field with generated expression that is of cast or date format.
        String expr = currPartitionField.metadata().getString(DELTA_GENERATION_EXPRESSION);
        ParsedGeneratedExpr parsedGeneratedExpr =
            ParsedGeneratedExpr.buildFromString(currPartitionField.name(), expr);
        if (ParsedGeneratedExpr.GeneratedExprType.CAST == parsedGeneratedExpr.generatedExprType) {
          partitionFields.add(
              getPartitionWithDateTransform(
                  currPartitionField.name(), parsedGeneratedExpr, internalSchema));
          itr.next(); // consume the field.
        } else if (ParsedGeneratedExpr.GeneratedExprType.DATE_FORMAT
            == parsedGeneratedExpr.generatedExprType) {
          partitionFields.add(
              getPartitionWithDateFormatTransform(
                  currPartitionField.name(), parsedGeneratedExpr, internalSchema));
          itr.next(); // consume the field.
        } else {
          // consume until we hit field with no generated expression or generated expression
          // that is not of type cast or date format.
          List<ParsedGeneratedExpr> parsedGeneratedExprs = new ArrayList<>();
          while (itr.hasNext()
              && currPartitionField.metadata().contains(DELTA_GENERATION_EXPRESSION)) {
            expr = currPartitionField.metadata().getString(DELTA_GENERATION_EXPRESSION);
            parsedGeneratedExpr =
                ParsedGeneratedExpr.buildFromString(currPartitionField.name(), expr);

            if (ParsedGeneratedExpr.GeneratedExprType.CAST == parsedGeneratedExpr.generatedExprType
                || ParsedGeneratedExpr.GeneratedExprType.DATE_FORMAT
                    == parsedGeneratedExpr.generatedExprType) {
              break;
            }
            parsedGeneratedExprs.add(parsedGeneratedExpr);
            itr.next(); // consume the field
            if (itr.hasNext()) {
              currPartitionField = itr.peek();
            }
          }
          partitionFields.add(
              getPartitionColumnsForHourOrDayOrMonthOrYear(parsedGeneratedExprs, internalSchema));
        }
      }
    }
    return partitionFields;
  }