Github user cloud-fan commented on a diff in the pull request: https://github.com/apache/spark/pull/14102#discussion_r74393971 --- Diff: sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/json/JacksonParser.scala --- @@ -35,184 +34,303 @@ import org.apache.spark.util.Utils private[json] class SparkSQLJsonProcessingException(msg: String) extends RuntimeException(msg) -object JacksonParser extends Logging { +class JacksonParser( + schema: StructType, + columnNameOfCorruptRecord: String, + options: JSONOptions) extends Logging { - def parse( - input: RDD[String], - schema: StructType, - columnNameOfCorruptRecords: String, - configOptions: JSONOptions): RDD[InternalRow] = { + import com.fasterxml.jackson.core.JsonToken._ + + // A `ValueConverter` is responsible for converting a value from `JsonParser` + // to a value in a field for `InternalRow`. + private type ValueConverter = (JsonParser) => Any + + // `ValueConverter`s for the root schema for all fields in the schema + private val rootConverter: ValueConverter = makeRootConverter(schema) - input.mapPartitions { iter => - parseJson(iter, schema, columnNameOfCorruptRecords, configOptions) + private val factory = new JsonFactory() + options.setJacksonOptions(factory) + + /** + * This function deals with the cases it fails to parse. This function will be called + * when exceptions are caught during converting. This functions also deals with `mode` option. + */ + private def failedRecord(record: String): Seq[InternalRow] = { + // create a row even if no corrupt record column is present + if (options.failFast) { + throw new RuntimeException(s"Malformed line in FAILFAST mode: $record") + } + if (options.dropMalformed) { + logWarning(s"Dropping malformed line: $record") + Nil + } else { + val row = new GenericMutableRow(schema.length) + for (corruptIndex <- schema.getFieldIndex(columnNameOfCorruptRecord)) { + require(schema(corruptIndex).dataType == StringType) + row.update(corruptIndex, UTF8String.fromString(record)) + } + Seq(row) } } /** - * Parse the current token (and related children) according to a desired schema - * This is a wrapper for the method `convertField()` to handle a row wrapped - * with an array. + * Create a converter which converts the JSON documents held by the `JsonParser` + * to a value according to a desired schema. This is a wrapper for the method + * `makeConverter()` to handle a row wrapped with an array. */ - def convertRootField( - factory: JsonFactory, - parser: JsonParser, - schema: DataType): Any = { - import com.fasterxml.jackson.core.JsonToken._ - (parser.getCurrentToken, schema) match { - case (START_ARRAY, st: StructType) => - // SPARK-3308: support reading top level JSON arrays and take every element - // in such an array as a row - convertArray(factory, parser, st) - - case (START_OBJECT, ArrayType(st, _)) => + def makeRootConverter(dataType: DataType): ValueConverter = dataType match { + case st: StructType => + val elementConverter = makeConverter(st) + val fieldConverters = st.map(_.dataType).map(makeConverter) + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case START_OBJECT => convertObject(parser, st, fieldConverters) + // SPARK-3308: support reading top level JSON arrays and take every element + // in such an array as a row + // + // For example, we support, the JSON data as below: + // + // [{"a":"str_a_1"}] + // [{"a":"str_a_2"}, {"b":"str_b_3"}] + // + // resulting in: + // + // List([str_a_1,null]) + // List([str_a_2,null], [null,str_b_3]) + // + case START_ARRAY => convertArray(parser, elementConverter) + } + + case ArrayType(st: StructType, _) => + val elementConverter = makeConverter(st) + val fieldConverters = st.map(_.dataType).map(makeConverter) + (parser: JsonParser) => parseJsonToken(parser, dataType) { // the business end of SPARK-3308: - // when an object is found but an array is requested just wrap it in a list - convertField(factory, parser, st) :: Nil + // when an object is found but an array is requested just wrap it in a list. + // This is being wrapped in `JacksonParser.parse`. + case START_OBJECT => convertObject(parser, st, fieldConverters) + case START_ARRAY => convertArray(parser, elementConverter) + } - case _ => - convertField(factory, parser, schema) - } + case _ => makeConverter(dataType) } - private def convertField( - factory: JsonFactory, - parser: JsonParser, - schema: DataType): Any = { - import com.fasterxml.jackson.core.JsonToken._ - (parser.getCurrentToken, schema) match { - case (null | VALUE_NULL, _) => - null + /** + * Create a converter which converts the JSON documents held by the `JsonParser` + * to a value according to a desired schema. + */ + private def makeConverter(dataType: DataType): ValueConverter = dataType match { + case BooleanType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_TRUE => true + case VALUE_FALSE => false + } - case (FIELD_NAME, _) => - parser.nextToken() - convertField(factory, parser, schema) - - case (VALUE_STRING, StringType) => - UTF8String.fromString(parser.getText) - - case (VALUE_STRING, _) if parser.getTextLength < 1 => - // guard the non string type - null - - case (VALUE_STRING, BinaryType) => - parser.getBinaryValue - - case (VALUE_STRING, DateType) => - val stringValue = parser.getText - if (stringValue.contains("-")) { - // The format of this string will probably be "yyyy-mm-dd". - DateTimeUtils.millisToDays(DateTimeUtils.stringToTime(parser.getText).getTime) - } else { - // In Spark 1.5.0, we store the data as number of days since epoch in string. - // So, we just convert it to Int. - stringValue.toInt - } + case ByteType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_NUMBER_INT => parser.getByteValue + } - case (VALUE_STRING, TimestampType) => - // This one will lose microseconds parts. - // See https://issues.apache.org/jira/browse/SPARK-10681. - DateTimeUtils.stringToTime(parser.getText).getTime * 1000L + case ShortType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_NUMBER_INT => parser.getShortValue + } - case (VALUE_NUMBER_INT, TimestampType) => - parser.getLongValue * 1000000L + case IntegerType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_NUMBER_INT => parser.getIntValue + } - case (_, StringType) => - val writer = new ByteArrayOutputStream() - Utils.tryWithResource(factory.createGenerator(writer, JsonEncoding.UTF8)) { - generator => generator.copyCurrentStructure(parser) - } - UTF8String.fromBytes(writer.toByteArray) - - case (VALUE_NUMBER_INT | VALUE_NUMBER_FLOAT, FloatType) => - parser.getFloatValue - - case (VALUE_STRING, FloatType) => - // Special case handling for NaN and Infinity. - val value = parser.getText - val lowerCaseValue = value.toLowerCase() - if (lowerCaseValue.equals("nan") || - lowerCaseValue.equals("infinity") || - lowerCaseValue.equals("-infinity") || - lowerCaseValue.equals("inf") || - lowerCaseValue.equals("-inf")) { - value.toFloat - } else { - throw new SparkSQLJsonProcessingException(s"Cannot parse $value as FloatType.") - } + case LongType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_NUMBER_INT => parser.getLongValue + } - case (VALUE_NUMBER_INT | VALUE_NUMBER_FLOAT, DoubleType) => - parser.getDoubleValue - - case (VALUE_STRING, DoubleType) => - // Special case handling for NaN and Infinity. - val value = parser.getText - val lowerCaseValue = value.toLowerCase() - if (lowerCaseValue.equals("nan") || - lowerCaseValue.equals("infinity") || - lowerCaseValue.equals("-infinity") || - lowerCaseValue.equals("inf") || - lowerCaseValue.equals("-inf")) { - value.toDouble - } else { - throw new SparkSQLJsonProcessingException(s"Cannot parse $value as DoubleType.") - } + case FloatType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_NUMBER_INT | VALUE_NUMBER_FLOAT => + parser.getFloatValue + + case VALUE_STRING => + // Special case handling for NaN and Infinity. + val value = parser.getText + val lowerCaseValue = value.toLowerCase + if (lowerCaseValue.equals("nan") || + lowerCaseValue.equals("infinity") || + lowerCaseValue.equals("-infinity") || + lowerCaseValue.equals("inf") || + lowerCaseValue.equals("-inf")) { + value.toFloat + } else { + throw new SparkSQLJsonProcessingException(s"Cannot parse $value as FloatType.") + } + } + + case DoubleType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_NUMBER_INT | VALUE_NUMBER_FLOAT => + parser.getDoubleValue + + case VALUE_STRING => + // Special case handling for NaN and Infinity. + val value = parser.getText + val lowerCaseValue = value.toLowerCase + if (lowerCaseValue.equals("nan") || + lowerCaseValue.equals("infinity") || + lowerCaseValue.equals("-infinity") || + lowerCaseValue.equals("inf") || + lowerCaseValue.equals("-inf")) { + value.toDouble + } else { + throw new SparkSQLJsonProcessingException(s"Cannot parse $value as DoubleType.") + } + } + + case StringType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_STRING => + UTF8String.fromString(parser.getText) + + case _ => + // Note that it always tries to convert the data as string without the case of failure. + val writer = new ByteArrayOutputStream() + Utils.tryWithResource(factory.createGenerator(writer, JsonEncoding.UTF8)) { + generator => generator.copyCurrentStructure(parser) + } + UTF8String.fromBytes(writer.toByteArray) + } + + case TimestampType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_STRING => + // This one will lose microseconds parts. + // See https://issues.apache.org/jira/browse/SPARK-10681. + DateTimeUtils.stringToTime(parser.getText).getTime * 1000L - case (VALUE_NUMBER_INT | VALUE_NUMBER_FLOAT, dt: DecimalType) => - Decimal(parser.getDecimalValue, dt.precision, dt.scale) + case VALUE_NUMBER_INT => + parser.getLongValue * 1000000L + } - case (VALUE_NUMBER_INT, ByteType) => - parser.getByteValue + case DateType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_STRING => + val stringValue = parser.getText + if (stringValue.contains("-")) { + // The format of this string will probably be "yyyy-mm-dd". + DateTimeUtils.millisToDays(DateTimeUtils.stringToTime(parser.getText).getTime) + } else { + // In Spark 1.5.0, we store the data as number of days since epoch in string. + // So, we just convert it to Int. + stringValue.toInt + } + } - case (VALUE_NUMBER_INT, ShortType) => - parser.getShortValue + case BinaryType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case VALUE_STRING => parser.getBinaryValue + } - case (VALUE_NUMBER_INT, IntegerType) => - parser.getIntValue + case dt: DecimalType => + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case (VALUE_NUMBER_INT | VALUE_NUMBER_FLOAT) => + Decimal(parser.getDecimalValue, dt.precision, dt.scale) + } - case (VALUE_NUMBER_INT, LongType) => - parser.getLongValue + case st: StructType => + val fieldConverters = st.map(_.dataType).map(makeConverter) + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case START_OBJECT => convertObject(parser, st, fieldConverters) + } - case (VALUE_TRUE, BooleanType) => - true + case at: ArrayType => + val elementConverter = makeConverter(at.elementType) + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case START_ARRAY => convertArray(parser, elementConverter) + } - case (VALUE_FALSE, BooleanType) => - false + case mt: MapType => + val valueConverter = makeConverter(mt.valueType) + (parser: JsonParser) => parseJsonToken(parser, dataType) { + case START_OBJECT => convertMap(parser, valueConverter) + } - case (START_OBJECT, st: StructType) => - convertObject(factory, parser, st) + case udt: UserDefinedType[_] => + makeConverter(udt.sqlType) - case (START_ARRAY, ArrayType(st, _)) => - convertArray(factory, parser, st) + case _ => + (parser: JsonParser) => + // Here, we pass empty `PartialFunction` so that this case can be + // handled as a failed conversion. It will throw an exception as + // long as the value is not null. + parseJsonToken(parser, dataType)(PartialFunction.empty[JsonToken, Any]) + } - case (START_OBJECT, MapType(StringType, kt, _)) => - convertMap(factory, parser, kt) + /** + * This handles nulls ahead before trying to check the tokens, and applies the conversion + * function and then checks failed the conversion afterward if the `f` fails to convert + * the value. + * + * In more details, it checks `FIELD_NAME` if exists and then skip. If this is called after + * `START_OBJECT`, then, the next token can be `FIELD_NAME`. Since the names are kept in + * `JacksonParser.convertObject`, this `FIELD_NAME` token can be skipped as below. When this + * is called after `START_ARRAY`, the tokens are consecutive tokens for values without + * `FIELD_NAME` until `END_ARRAY`. In this case, we don't have to skip. --- End diff -- it's good to know this, but do we really need to put it in comments? It seems not that helpful for people to understand the code. We just need some comments `case FIELD_NAME =>` to explain why we need to skip, i.e. there are useless `FIELD_NAME`s between `START_OBJECT` and `END_OBJECT` tokens.
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