tech.mlsql.arrow.ArrowUtils.scala Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of pyjava-3.3_2.12 Show documentation
Communication between Python And Java with Apache Arrow.
The newest version!
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package tech.mlsql.arrow

import org.apache.arrow.memory.RootAllocator
import org.apache.arrow.vector.types.pojo.{ArrowType, Field, FieldType, Schema}
import org.apache.arrow.vector.types.{DateUnit, FloatingPointPrecision, TimeUnit}
import org.apache.spark.sql.SparkUtils
import org.apache.spark.sql.types._

import scala.collection.JavaConverters._

object ArrowUtils {

  val rootAllocator = new RootAllocator(Long.MaxValue)

  // todo: support more types.

  /** Maps data type from Spark to Arrow. NOTE: timeZoneId required for TimestampTypes */
  def toArrowType(dt: DataType, timeZoneId: String): ArrowType = {
    SparkUtils.isFixDecimal(dt).getOrElse {
      dt match {
        case BooleanType => ArrowType.Bool.INSTANCE
        case ByteType => new ArrowType.Int(8, true)
        case ShortType => new ArrowType.Int(8 * 2, true)
        case IntegerType => new ArrowType.Int(8 * 4, true)
        case LongType => new ArrowType.Int(8 * 8, true)
        case FloatType => new ArrowType.FloatingPoint(FloatingPointPrecision.SINGLE)
        case DoubleType => new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)
        case StringType => ArrowType.Utf8.INSTANCE
        case BinaryType => ArrowType.Binary.INSTANCE
        case DateType => new ArrowType.Date(DateUnit.DAY)
        case TimestampType =>
          if (timeZoneId == null) {
            throw new UnsupportedOperationException(
              s"${TimestampType.catalogString} must supply timeZoneId parameter")
          } else {
            new ArrowType.Timestamp(TimeUnit.MICROSECOND, timeZoneId)
          }
        case _ =>

          throw new UnsupportedOperationException(s"Unsupported data type: ${dt.catalogString}")
      }
    }

  }

  def fromArrowType(dt: ArrowType): DataType = dt match {
    case ArrowType.Bool.INSTANCE => BooleanType
    case int: ArrowType.Int if int.getIsSigned && int.getBitWidth == 8 => ByteType
    case int: ArrowType.Int if int.getIsSigned && int.getBitWidth == 8 * 2 => ShortType
    case int: ArrowType.Int if int.getIsSigned && int.getBitWidth == 8 * 4 => IntegerType
    case int: ArrowType.Int if int.getIsSigned && int.getBitWidth == 8 * 8 => LongType
    case float: ArrowType.FloatingPoint
      if float.getPrecision() == FloatingPointPrecision.SINGLE => FloatType
    case float: ArrowType.FloatingPoint
      if float.getPrecision() == FloatingPointPrecision.DOUBLE => DoubleType
    case ArrowType.Utf8.INSTANCE => StringType
    case ArrowType.Binary.INSTANCE => BinaryType
    case d: ArrowType.Decimal => DecimalType(d.getPrecision, d.getScale)
    case date: ArrowType.Date if date.getUnit == DateUnit.DAY => DateType
    case ts: ArrowType.Timestamp if ts.getUnit == TimeUnit.MICROSECOND => TimestampType
    case _ => throw new UnsupportedOperationException(s"Unsupported data type: $dt")
  }

  /** Maps field from Spark to Arrow. NOTE: timeZoneId required for TimestampType */
  def toArrowField(
                    name: String, dt: DataType, nullable: Boolean, timeZoneId: String): Field = {
    dt match {
      case ArrayType(elementType, containsNull) =>
        val fieldType = new FieldType(nullable, ArrowType.List.INSTANCE, null)
        new Field(name, fieldType,
          Seq(toArrowField("element", elementType, containsNull, timeZoneId)).asJava)
      case StructType(fields) =>
        val fieldType = new FieldType(nullable, ArrowType.Struct.INSTANCE, null)
        new Field(name, fieldType,
          fields.map { field =>
            toArrowField(field.name, field.dataType, field.nullable, timeZoneId)
          }.toSeq.asJava)
      case dataType =>
        val fieldType = new FieldType(nullable, toArrowType(dataType, timeZoneId), null)
        new Field(name, fieldType, Seq.empty[Field].asJava)
    }
  }

  def fromArrowField(field: Field): DataType = {
    field.getType match {
      case ArrowType.List.INSTANCE =>
        val elementField = field.getChildren().get(0)
        val elementType = fromArrowField(elementField)
        ArrayType(elementType, containsNull = elementField.isNullable)
      case ArrowType.Struct.INSTANCE =>
        val fields = field.getChildren().asScala.map { child =>
          val dt = fromArrowField(child)
          StructField(child.getName, dt, child.isNullable)
        }
        StructType(fields)
      case arrowType => fromArrowType(arrowType)
    }
  }

  /** Maps schema from Spark to Arrow. NOTE: timeZoneId required for TimestampType in StructType */
  def toArrowSchema(schema: StructType, timeZoneId: String): Schema = {
    new Schema(schema.map { field =>
      toArrowField(field.name, field.dataType, field.nullable, timeZoneId)
    }.asJava)
  }

  def fromArrowSchema(schema: Schema): StructType = {
    StructType(schema.getFields.asScala.map { field =>
      val dt = fromArrowField(field)
      StructField(field.getName, dt, field.isNullable)
    })
  }


}