org.apache.flink.table.expressions.Cast.scala Maven / Gradle / Ivy
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package org.apache.flink.table.expressions
import org.apache.flink.table.calcite.FlinkTypeFactory
import org.apache.flink.table.plan.logical.LogicalExprVisitor
import org.apache.flink.table.types.InternalType
import org.apache.flink.table.typeutils.TypeCoercion
import org.apache.flink.table.validate._
import org.apache.calcite.rex.RexNode
import org.apache.calcite.tools.RelBuilder
case class Cast(child: Expression, resultType: InternalType) extends UnaryExpression {
override def toString = s"$child.cast($resultType)"
override private[flink] def toRexNode(implicit relBuilder: RelBuilder): RexNode = {
val typeFactory = relBuilder.getTypeFactory.asInstanceOf[FlinkTypeFactory]
val childRexNode = child.toRexNode
relBuilder
.getRexBuilder
// we use abstract cast here because RelBuilder.cast() has to many side effects
.makeAbstractCast(
typeFactory.createTypeFromInternalType(resultType, childRexNode.getType.isNullable),
childRexNode)
}
override private[flink] def makeCopy(anyRefs: Array[AnyRef]): this.type = {
val child: Expression = anyRefs.head.asInstanceOf[Expression]
copy(child, resultType).asInstanceOf[this.type]
}
override private[flink] def validateInput(): ValidationResult = {
if (TypeCoercion.canCast(child.resultType, resultType)) {
ValidationSuccess
} else {
ValidationFailure(s"Unsupported cast from ${child.resultType} to $resultType")
}
}
override def accept[T](logicalExprVisitor: LogicalExprVisitor[T]): T =
logicalExprVisitor.visit(this)
}