iRakson commented on a change in pull request #27759: [SPARK-31008][SQL] Support json_array_length function URL: https://github.com/apache/spark/pull/27759#discussion_r403477043
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/jsonExpressions.scala ########## @@ -781,3 +781,68 @@ case class SchemaOfJson( override def prettyName: String = "schema_of_json" } + +/** + * A function that returns the number of elements in outer JSON array. + */ +@ExpressionDescription( + usage = "_FUNC_(jsonArray) - Returns the number of elements in outer JSON array.", + arguments = """ + Arguments: + * jsonArray - A JSON array. An Exception is thrown if any other valid JSON strings are passed. + `NULL` is returned in case of invalid JSON. + """, + examples = """ + Examples: + > SELECT _FUNC_('[1,2,3,4]'); + 4 + > SELECT _FUNC_('[1,2,3,{"f1":1,"f2":[5,6]},4]'); + 5 + > SELECT _FUNC_('[1,2'); + NULL + """, + since = "3.1.0" +) +case class LengthOfJsonArray(child: Expression) + extends UnaryExpression with CodegenFallback { + override def dataType: DataType = IntegerType + override def nullable: Boolean = true + override def prettyName: String = "json_array_length" + + override def eval(input: InternalRow): Any = { + val json = child.eval(input).asInstanceOf[UTF8String] + try { + Utils.tryWithResource(CreateJacksonParser.utf8String(SharedFactory.jsonFactory, json)) { + parser => { + // return null if null array is encountered. + if (parser.nextToken() == null) { + return null + } + // Parse the array to compute its length. + parseCounter(parser, input) + } + } + } catch { + case _: JsonProcessingException | _: IOException => null Review comment: I think we do not need to catch `NullPointerException` here. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org