org.apache.spark.sql.catalyst.expressions.misc.scala Maven / Gradle / Ivy

/*
 * 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 org.apache.spark.sql.catalyst.expressions

import java.util.UUID

import org.apache.spark.sql.catalyst.InternalRow
import org.apache.spark.sql.catalyst.expressions.codegen._
import org.apache.spark.sql.catalyst.expressions.codegen.Block._
import org.apache.spark.sql.catalyst.util.RandomUUIDGenerator
import org.apache.spark.sql.types._
import org.apache.spark.unsafe.types.UTF8String

/**
 * Print the result of an expression to stderr (used for debugging codegen).
 */
case class PrintToStderr(child: Expression) extends UnaryExpression {

  override def dataType: DataType = child.dataType

  protected override def nullSafeEval(input: Any): Any = {
    // scalastyle:off println
    System.err.println(outputPrefix + input)
    // scalastyle:on println
    input
  }

  private val outputPrefix = s"Result of ${child.simpleString} is "

  override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
    val outputPrefixField = ctx.addReferenceObj("outputPrefix", outputPrefix)
    nullSafeCodeGen(ctx, ev, c =>
      s"""
         | System.err.println($outputPrefixField + $c);
         | ${ev.value} = $c;
       """.stripMargin)
  }
}

/**
 * A function throws an exception if 'condition' is not true.
 */
@ExpressionDescription(
  usage = "_FUNC_(expr) - Throws an exception if `expr` is not true.",
  examples = """
    Examples:
      > SELECT _FUNC_(0 < 1);
       NULL
  """)
case class AssertTrue(child: Expression) extends UnaryExpression with ImplicitCastInputTypes {

  override def nullable: Boolean = true

  override def inputTypes: Seq[DataType] = Seq(BooleanType)

  override def dataType: DataType = NullType

  override def prettyName: String = "assert_true"

  private val errMsg = s"'${child.simpleString}' is not true!"

  override def eval(input: InternalRow) : Any = {
    val v = child.eval(input)
    if (v == null || java.lang.Boolean.FALSE.equals(v)) {
      throw new RuntimeException(errMsg)
    } else {
      null
    }
  }

  override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
    val eval = child.genCode(ctx)

    // Use unnamed reference that doesn't create a local field here to reduce the number of fields
    // because errMsgField is used only when the value is null or false.
    val errMsgField = ctx.addReferenceObj("errMsg", errMsg)
    ExprCode(code = code"""${eval.code}
       |if (${eval.isNull} || !${eval.value}) {
       |  throw new RuntimeException($errMsgField);
       |}""".stripMargin, isNull = TrueLiteral,
      value = JavaCode.defaultLiteral(dataType))
  }

  override def sql: String = s"assert_true(${child.sql})"
}

/**
 * Returns the current database of the SessionCatalog.
 */
@ExpressionDescription(
  usage = "_FUNC_() - Returns the current database.",
  examples = """
    Examples:
      > SELECT _FUNC_();
       default
  """)
case class CurrentDatabase() extends LeafExpression with Unevaluable {
  override def dataType: DataType = StringType
  override def foldable: Boolean = true
  override def nullable: Boolean = false
  override def prettyName: String = "current_database"
}

// scalastyle:off line.size.limit
@ExpressionDescription(
  usage = """_FUNC_() - Returns an universally unique identifier (UUID) string. The value is returned as a canonical UUID 36-character string.""",
  examples = """
    Examples:
      > SELECT _FUNC_();
       46707d92-02f4-4817-8116-a4c3b23e6266
  """,
  note = "The function is non-deterministic.")
// scalastyle:on line.size.limit
case class Uuid(randomSeed: Option[Long] = None) extends LeafExpression with Stateful
    with ExpressionWithRandomSeed {

  def this() = this(None)

  override def withNewSeed(seed: Long): Uuid = Uuid(Some(seed))

  override lazy val resolved: Boolean = randomSeed.isDefined

  override def nullable: Boolean = false

  override def dataType: DataType = StringType

  @transient private[this] var randomGenerator: RandomUUIDGenerator = _

  override protected def initializeInternal(partitionIndex: Int): Unit =
    randomGenerator = RandomUUIDGenerator(randomSeed.get + partitionIndex)

  override protected def evalInternal(input: InternalRow): Any =
    randomGenerator.getNextUUIDUTF8String()

  override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
    val randomGen = ctx.freshName("randomGen")
    ctx.addMutableState("org.apache.spark.sql.catalyst.util.RandomUUIDGenerator", randomGen,
      forceInline = true,
      useFreshName = false)
    ctx.addPartitionInitializationStatement(s"$randomGen = " +
      "new org.apache.spark.sql.catalyst.util.RandomUUIDGenerator(" +
      s"${randomSeed.get}L + partitionIndex);")
    ev.copy(code = code"final UTF8String ${ev.value} = $randomGen.getNextUUIDUTF8String();",
      isNull = FalseLiteral)
  }

  override def freshCopy(): Uuid = Uuid(randomSeed)
}