Github user twalthr commented on a diff in the pull request:
https://github.com/apache/flink/pull/4710#discussion_r140778244
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/sources/definedTimeAttributes.scala
---
@@ -30,10 +30,16 @@ package org.apache.flink.table.sources
trait DefinedRowtimeAttribute {
/**
- * Defines a name of the event-time attribute that represents Flink's
- * event-time. Null if no rowtime should be available.
+ * Defines a name of the event-time attribute that represents Flink's
event-time, i.e., an
+ * attribute that is aligned with the watermarks of the table.
+ * An attribute with the given name must be present in the schema of
the [[TableSource]].
+ * The attribute must be of type [[Long]] or [[java.sql.Timestamp]].
*
- * The field will be appended to the schema provided by the
[[TableSource]].
+ * The method should return null if no rowtime attribute is defined.
+ *
+ * @return The name of the field that represents the event-time field
and which is aligned
+ * with the watermarks of the table. The field must be present
in the schema of the
--- End diff --
Some here.
---
