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https://issues.apache.org/jira/browse/FLINK-3754?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15280151#comment-15280151
]
ASF GitHub Bot commented on FLINK-3754:
---------------------------------------
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.
> Add a validation phase before construct RelNode using TableAPI
> --------------------------------------------------------------
>
> Key: FLINK-3754
> URL: https://issues.apache.org/jira/browse/FLINK-3754
> Project: Flink
> Issue Type: Improvement
> Components: Table API
> Affects Versions: 1.0.0
> Reporter: Yijie Shen
> Assignee: Yijie Shen
>
> Unlike sql string's execution, which have a separate validation phase before
> RelNode construction, Table API lacks the counterparts and the validation is
> scattered in many places.
> I suggest to add a single validation phase and detect problems as early as
> possible.
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