Github user twalthr commented on a diff in the pull request: https://github.com/apache/flink/pull/1958#discussion_r62852367 --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/expressions/cast.scala --- @@ -20,19 +20,55 @@ package org.apache.flink.api.table.expressions import org.apache.calcite.rex.RexNode import org.apache.calcite.tools.RelBuilder -import org.apache.flink.api.common.typeinfo.TypeInformation +import org.apache.flink.api.common.typeinfo.BasicTypeInfo._ +import org.apache.flink.api.common.typeinfo.{NumericTypeInfo, TypeInformation} import org.apache.flink.api.table.typeutils.TypeConverter +import org.apache.flink.api.table.validate._ -case class Cast(child: Expression, tpe: TypeInformation[_]) extends UnaryExpression { +case class Cast(child: Expression, resultType: TypeInformation[_]) extends UnaryExpression { - override def toString = s"$child.cast($tpe)" + override def toString = s"$child.cast($resultType)" override def toRexNode(implicit relBuilder: RelBuilder): RexNode = { - relBuilder.cast(child.toRexNode, TypeConverter.typeInfoToSqlType(tpe)) + relBuilder.cast(child.toRexNode, TypeConverter.typeInfoToSqlType(resultType)) } - override def makeCopy(anyRefs: Seq[AnyRef]): this.type = { + override def makeCopy(anyRefs: Array[AnyRef]): this.type = { val child: Expression = anyRefs.head.asInstanceOf[Expression] - copy(child, tpe).asInstanceOf[this.type] + copy(child, resultType).asInstanceOf[this.type] + } + + override def validateInput(): ExprValidationResult = { + if (Cast.canCast(child.resultType, resultType)) { + ValidationSuccess + } else { + ValidationFailure(s"Unsupported cast from ${child.resultType} to $resultType") + } + } +} + +object Cast { --- End diff -- I would also move this into `typeutils`. We'll may need it somewhere else too.
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