DayTimeIntervalType.scala

/*
 * 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.
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package org.apache.spark.sql.types

import scala.math.Ordering
import scala.reflect.runtime.universe.typeTag

import org.apache.spark.annotation.Unstable
import org.apache.spark.sql.errors.QueryCompilationErrors
import org.apache.spark.sql.types.DayTimeIntervalType.fieldToString

/**
 * The type represents day-time intervals of the SQL standard. A day-time interval is made up
 * of a contiguous subset of the following fields:
 *   - SECOND, seconds within minutes and possibly fractions of a second [0..59.999999],
 *   - MINUTE, minutes within hours [0..59],
 *   - HOUR, hours within days [0..23],
 *   - DAY, days in the range [0..106751991].
 *
 * `DayTimeIntervalType` represents positive as well as negative day-time intervals.
 *
 * @param startField The leftmost field which the type comprises of. Valid values:
 *                   0 (DAY), 1 (HOUR), 2 (MINUTE), 3 (SECOND).
 * @param endField The rightmost field which the type comprises of. Valid values:
 *                 0 (DAY), 1 (HOUR), 2 (MINUTE), 3 (SECOND).
 *
 * @since 3.2.0
 */
@Unstable
case class DayTimeIntervalType(startField: Byte, endField: Byte) extends AtomicType {
  /**
   * Internally, values of day-time intervals are stored in `Long` values as amount of time in terms
   * of microseconds that are calculated by the formula:
   *   -/+ (24*60*60 * DAY + 60*60 * HOUR + 60 * MINUTE + SECOND) * 1000000
   */
  private[sql] type InternalType = Long

  @transient private[sql] lazy val tag = typeTag[InternalType]

  private[sql] val ordering = implicitly[Ordering[InternalType]]

  /**
   * The day-time interval type has constant precision. A value of the type always occupies 8 bytes.
   * The DAY field is constrained by the upper bound 106751991 to fit to `Long`.
   */
  override def defaultSize: Int = 8

  private[spark] override def asNullable: DayTimeIntervalType = this

  override val typeName: String = {
    val startFieldName = fieldToString(startField)
    val endFieldName = fieldToString(endField)
    if (startFieldName == endFieldName) {
      s"interval $startFieldName"
    } else if (startField < endField) {
      s"interval $startFieldName to $endFieldName"
    } else {
      throw QueryCompilationErrors.invalidDayTimeIntervalType(startFieldName, endFieldName)
    }
  }
}

/**
 * Extra factory methods and pattern matchers for DayTimeIntervalType.
 *
 * @since 3.2.0
 */
@Unstable
case object DayTimeIntervalType extends AbstractDataType {
  val DAY: Byte = 0
  val HOUR: Byte = 1
  val MINUTE: Byte = 2
  val SECOND: Byte = 3
  val dayTimeFields = Seq(DAY, HOUR, MINUTE, SECOND)

  def fieldToString(field: Byte): String = field match {
    case DAY => "day"
    case HOUR => "hour"
    case MINUTE => "minute"
    case SECOND => "second"
    case invalid => throw QueryCompilationErrors.invalidDayTimeField(invalid)
  }

  val DEFAULT = DayTimeIntervalType(DAY, SECOND)

  def apply(): DayTimeIntervalType = DEFAULT

  override private[sql] def defaultConcreteType: DataType = DEFAULT

  override private[sql] def acceptsType(other: DataType): Boolean = {
    other.isInstanceOf[DayTimeIntervalType]
  }

  override private[sql] def simpleString: String = defaultConcreteType.simpleString
}