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Hyukjin Kwon resolved SPARK-28889. ---------------------------------- Resolution: Later > Allow UDTs to define custom casting behavior > -------------------------------------------- > > Key: SPARK-28889 > URL: https://issues.apache.org/jira/browse/SPARK-28889 > Project: Spark > Issue Type: Improvement > Components: SQL > Affects Versions: 2.4.3 > Reporter: Zachary S Ennenga > Priority: Minor > > Looking at `org.apache.spark.sql.catalyst.expressions.Cast`, UDTs do not > support any sort of casting except for identity casts, IE: > {code:java} > case (udt1: UserDefinedType[_], udt2: UserDefinedType[_]) if udt1.userClass > == udt2.userClass => > true > {code} > I propose we add an additional piece of functionality here to allow UDTs to > define their own canCast and cast functions to allow users to define their > own cast mechanisms. > An example of how this might look: > {code:java} > case (fromType, toType: UserDefinedType[_]) => > toType.canCast(fromType) // Returns boolean > {code} > {code:java} > case (fromType, toType: UserDefinedType[_]) => > toType.cast(fromType) // Returns Casting function > {code} > The UDT base class would contain a default implementation that replicates > current behavior (IE no casting). -- This message was sent by Atlassian Jira (v8.3.2#803003) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org