Github user wuchong commented on a diff in the pull request: https://github.com/apache/flink/pull/2653#discussion_r88614200 --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/functions/utils/UserDefinedFunctionUtils.scala --- @@ -162,24 +191,107 @@ object UserDefinedFunctionUtils { } /** + * Internal method of [[ScalarFunction#getResultType()]] that does some pre-checking and uses + * [[TypeExtractor]] as default return type inference. + */ + def getResultType( + tableFunction: TableFunction[_], + signature: Array[Class[_]]) + : TypeInformation[_] = { + // find method for signature + val evalMethod = tableFunction.getEvalMethods + .find(m => signature.sameElements(m.getParameterTypes)) + .getOrElse(throw new ValidationException("Given signature is invalid.")) + + val userDefinedTypeInfo = tableFunction.getResultType + if (userDefinedTypeInfo != null) { + userDefinedTypeInfo + } else { + try { + TypeExtractor.getForClass(evalMethod.getReturnType) + } catch { + case ite: InvalidTypesException => + throw new ValidationException( + s"Return type of table function '$this' cannot be " + + s"automatically determined. Please provide type information manually.") + } + } + } + + /** * Returns the return type of the evaluation method matching the given signature. */ def getResultTypeClass( - scalarFunction: ScalarFunction, + function: EvaluableFunction, signature: Array[Class[_]]) : Class[_] = { // find method for signature - val evalMethod = scalarFunction.getEvalMethods + val evalMethod = function.getEvalMethods .find(m => signature.sameElements(m.getParameterTypes)) .getOrElse(throw new IllegalArgumentException("Given signature is invalid.")) evalMethod.getReturnType } /** - * Prints all signatures of a [[ScalarFunction]]. + * Prints all signatures of a [[EvaluableFunction]]. */ - def signaturesToString(scalarFunction: ScalarFunction): String = { - scalarFunction.getSignatures.map(signatureToString).mkString(", ") + def signaturesToString(function: EvaluableFunction): String = { + function.getSignatures.map(signatureToString).mkString(", ") } + /** + * Returns field names and field positions for a given [[TypeInformation]]. + * + * Field names are automatically extracted for + * [[org.apache.flink.api.common.typeutils.CompositeType]]. + * + * @param inputType The TypeInformation extract the field names and positions from. + * @return A tuple of two arrays holding the field names and corresponding field positions. + */ + def getFieldInfo(inputType: TypeInformation[_]) + : (Array[String], Array[Int]) = { + val fieldNames: Array[String] = inputType match { + case t: TupleTypeInfo[_] => t.getFieldNames --- End diff -- Yes, you are right. We can use `CompositeType` here.
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