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The java SDK for clickzetta's Lakehouse

There is a newer version: 2.0.0

package com.clickzetta.client.jdbc.arrow;

import com.clickzetta.client.jdbc.arrow.SqlTypes;
import org.apache.calcite.avatica.ColumnMetaData;
import org.apache.calcite.avatica.proto.Common;
import org.apache.calcite.avatica.proto.Common.ColumnMetaData.Builder;
import com.clickzetta.client.jdbc.core.CZColumnMetaData;

import java.sql.Types;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * Convert Fields To Column MetaData List functions.
 */
public final class ConvertUtils {

  private ConvertUtils() {
  }

  /**
   * Convert Fields To Column MetaData List functions.
   *
   * @param fields list of {@link CZColumnMetaData}.
   * @return list of {@link ColumnMetaData}.
   */
  public static List convertToColumnMetaDataList(final List fields) {
    return Stream.iterate(0, Math::incrementExact).limit(fields.size())
      .map(index -> {
        final CZColumnMetaData field = fields.get(index);

        final Builder builder = Common.ColumnMetaData.newBuilder()
          .setOrdinal(index)
          .setColumnName(field.getColumnName())
          .setLabel(field.getColumnName())
          .setNullable(field.isNullable());

        setOnColumnMetaDataBuilder(builder, field);

        builder.setType(Common.AvaticaType.newBuilder()
          .setId(SqlTypes.getSqlTypeIdFromCZColumnMetaData(field))
          .setName(SqlTypes.getSqlTypeNameFromCZColumnMetaData(field))
          .build());

        return ColumnMetaData.fromProto(builder.build());
      }).collect(Collectors.toList());
  }

  /**
   * Set on Column MetaData Builder.
   *
   * @param builder          {@link Builder}
   * @param czColumnMetaData {@link CZColumnMetaData}
   */
  public static void setOnColumnMetaDataBuilder(final Builder builder,
                                                final CZColumnMetaData czColumnMetaData) {
    int sqlType = czColumnMetaData.getColumnType();
    if (sqlType == Types.DECIMAL) {
      builder.setPrecision(czColumnMetaData.getPrecision());
      builder.setScale(czColumnMetaData.getScale());
    }
  }
}