Packages

  • package root
    Definition Classes
    root
  • package io
    Definition Classes
    root
  • package dylemma
    Definition Classes
    io
  • package spac

    SPaC (short for "Streaming Parser Combinators") is a library for building stream consumers in a declarative style, specialized for tree-like data types like XML and JSON.

    SPaC (short for "Streaming Parser Combinators") is a library for building stream consumers in a declarative style, specialized for tree-like data types like XML and JSON.

    Many utilities for handling XML and JSON data involve parsing the entire "document" to some DOM model, then inspecting and transforming that model to extract information. The downside to these utilities is that when the document is very large, the DOM may not fit in memory. The workaround for this type of problem is to treat the document as a stream of "events", e.g. "StartElement" and "EndElement" for XML, or "StartObject" and "EndObject" for JSON. The downside to this workaround is that writing code to handle these streams can be complicated and error-prone, especially when the DOM is complicated.

    SPaC's goal is to drastically simplify the process of creating code to handle these streams.

    This package contains the "core" SPaC traits; Parser, Transformer, Splitter, and ContextMatcher.

    See the xml and json subpackages (provided by the xml-spac and json-spac libraries respectively) for specific utilities related to handling XML and JSON event streams.

    Definition Classes
    dylemma
  • package json

    This package provides extensions to the core "spac" library which allow for the handling of JSON data.

    This package provides extensions to the core "spac" library which allow for the handling of JSON data.

    Rather than creating explicit classes that extend Parser, Transformer, and Splitter, this package provides type aliases and implicit extensions. For example, JsonParser[A] is just a type alias for Parser[JsonEvent, A], and JsonParser is just a call to Parser[JsonEvent].

    Implicit JsonParsers are available for each of the JSON primitive types:

    • string
    • number (expressed as Int, Long, Float, or Double)
    • boolean
    • null (expressed as None.type)

    Helpers are available for parsing JSON arrays and objects:

    • JsonParser.listOf[A] to parse an array where each value is an A
    • JsonParser.objectOf[A] to parse an object where the value for each field an A
    • JsonParser.objectOfNullable[A] to parse an object where the value for each field is either null or an A, filtering out the nulls
    • JsonParser.fieldOf[A](fieldName) to parse a specific field from an object

    A DSL for creating json-specific ContextMatchers is provided to make it more convenient to call Splitter.json. For example:

    Splitter.json("foo" \ "bar").as[String].parseFirst

    Can be used to capture rootJson.foo.bar as a String in

    {
      "foo": {
        "bar": "hello"
      }
    }

    To "split" values inside arrays, index-related context matchers are available, e.g.

    Splitter.json("foo" \ anyIndex).as[Int].parseToList

    Can be used to capture each of the numbers in the "foo" array in

    {
      "foo": [1, 2, 3]
    }

    A note about JsonEvents in spac: JSON doesn't have any explicit markers for when a field ends, or when an array index starts or ends; those context changes are essentially inferred by the presence of some other event. For example, instead of a "field end" event, typically there will be either a new "field start" or a token representing the end of the current object. With spac, splitters and context matchers generally operate under the assumption that a "stack push" event (like a field start) will eventually be followed by a corresponding "stack pop" event (i.e. field end).

    To allow for this, these "inferred" events (FieldEnd, IndexStart, IndexEnd) are explicitly represented as JsonEvents in the stream being parsed. Keep this in mind when creating JSON ContextMatchers:

    • field-related matchers will match a stack like case ObjectStart :: FieldStart(_) :: _
    • index-related matchers will match a stack like case ArrayStart :: IndexStart(_) :: _
    Definition Classes
    spac
  • Fs2DataSource
  • JacksonSource
  • JsonEvent
  • JsonParserApplyOps
  • JsonSplitterApplyOps
  • JsonSplitterOps
  • JsonStackElem
  • JsonStackPop
  • JsonValueEvent
c

io.dylemma.spac.json

JsonParserApplyOps

implicit final class JsonParserApplyOps extends AnyVal

Provides JSON-specific Parser constructor methods to the JsonParser object, for example JsonParser.fieldOf.

Technically JsonParser is not a companion object, it is a partially-applied version of the Parser companion object which binds the input type to JsonEvent, so "companion methods" must instead be added as extension methods.

Source
package.scala
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Inherited
  1. JsonParserApplyOps
  2. AnyVal
  3. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new JsonParserApplyOps(parserApply: ParserApplyWithBoundInput[JsonEvent])

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    Any
  2. final def ##: Int
    Definition Classes
    Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from JsonParserApplyOps toany2stringadd[JsonParserApplyOps] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (JsonParserApplyOps, B)
    Implicit
    This member is added by an implicit conversion from JsonParserApplyOps toArrowAssoc[JsonParserApplyOps] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    Any
  6. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  7. def ensuring(cond: (JsonParserApplyOps) => Boolean, msg: => Any): JsonParserApplyOps
    Implicit
    This member is added by an implicit conversion from JsonParserApplyOps toEnsuring[JsonParserApplyOps] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  8. def ensuring(cond: (JsonParserApplyOps) => Boolean): JsonParserApplyOps
    Implicit
    This member is added by an implicit conversion from JsonParserApplyOps toEnsuring[JsonParserApplyOps] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  9. def ensuring(cond: Boolean, msg: => Any): JsonParserApplyOps
    Implicit
    This member is added by an implicit conversion from JsonParserApplyOps toEnsuring[JsonParserApplyOps] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  10. def ensuring(cond: Boolean): JsonParserApplyOps
    Implicit
    This member is added by an implicit conversion from JsonParserApplyOps toEnsuring[JsonParserApplyOps] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def fieldOf[T](fieldName: String, parser: JsonParser[T])(implicit arg0: TypeName[T], callerPos: CallerPos): JsonParser[T]

    A JsonParser that parses a JSON object by parsing the given mandatory field with the given JsonParser[T].

    A JsonParser that parses a JSON object by parsing the given mandatory field with the given JsonParser[T].

    Note that if the given parser is available implicitly, you can use the other fieldOf signature.

    The returned parser will fail if the first event is not an ObjectStart, or if the expected field does not appear inside the object, or if the value of the expected field causes the underlying parser to fail.

    This is a shortcut for Splitter.json(fieldName).as[T].parseFirst.

    E.g.

    val rawJson = """{ "foo": 1, "bar": true }"""
    val parser = JsonParser.fieldOf[Boolean]("bar")
    parser.parse(rawJson) // returns `true`
    T

    The type of the extracted value

    fieldName

    The name of the expected field

    parser

    The underlying parser used to parse the value inside the expected field in the object

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses the given field from a JSON object as a value of type T

  12. def fieldOf[T](fieldName: String)(implicit arg0: TypeName[T], arg1: JsonParser[T], callerPos: CallerPos): JsonParser[T]

    A JsonParser that parses a JSON object by parsing the given mandatory field with the implicitly-available JsonParser[T].

    A JsonParser that parses a JSON object by parsing the given mandatory field with the implicitly-available JsonParser[T].

    The returned parser will fail if the first event is not an ObjectStart, or if the expected field does not appear inside the object, or if the value of the expected field causes the underlying parser to fail.

    This is a shortcut for Splitter.json(fieldName).as[T].parseFirst.

    E.g.

    val rawJson = """{ "foo": 1, "bar": true }"""
    val parser = JsonParser.fieldOf[Boolean]("bar")
    parser.parse(rawJson) // returns `true`
    T

    The type of the extracted value

    fieldName

    The name of the expected field

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses the given field from a JSON object as a value of type T

  13. def forBoolean: JsonParser[Boolean]

    A JsonParser that captures the Boolean value from a JBool event, failing if the first event is not a JBool.

  14. def forDouble: JsonParser[Double]

    A JsonParser that captures a JDouble event as a Double value, failing if the first event is not a JDouble.

  15. def forFloat: JsonParser[Float]

    A JsonParser that captures a JDouble event as a Float value, failing if the first event is not a JDouble.

  16. def forInt: JsonParser[Int]

    A JsonParser that captures a JLong event as an Int value, failing if the first event is not a JLong.

  17. def forLong: JsonParser[Long]

    A JsonParser that captures a JLong event as a Long value, failing if the first event is not a JLong.

  18. def forNull: JsonParser[None.type]

    A JsonParser that returns None upon encountering a JNull event, failing upon encountering any other event or an EOF.

  19. def forPrimitive[A](describePrimitive: String, matchPrimitive: (JsonEvent) => Option[A]): JsonParser[A]

    Creates a JsonParser which captures the first JsonEvent it sees, expecting a primitive that can satisfy the matchPrimitive function.

    Creates a JsonParser which captures the first JsonEvent it sees, expecting a primitive that can satisfy the matchPrimitive function.

    This is the low-level method used to implement the forString, forInt, etc parsers. Its main use outside of those is if you want to create a parser that handles multiple different primitives without resorting to the use of orElse.

    A

    The type of the extracted value

    describePrimitive

    A message describing the type of event that this parser expects. Used to construct a SpacException if the matchPrimitive returns None

    matchPrimitive

    A function used to extract a value from the first JsonEvent this parser's handler encounters.

    returns

    A JsonParser which attempts to extract some value from the first event it encounters, throwing a SpacException if it cannot

  20. def forString: JsonParser[String]

    A JsonParser that captures the string value from a JsString event, failing if the first event is not a JsString.

  21. def getClass(): Class[_ <: AnyVal]
    Definition Classes
    AnyVal → Any
  22. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  23. def listOf[T](parser: JsonParser[T])(implicit arg0: TypeName[T], callerPos: CallerPos): JsonParser[List[T]]

    A JsonParser that parses a JSON array by parsing each item in the array via the given parser, collecting the values to a List.

    A JsonParser that parses a JSON array by parsing each item in the array via the given parser, collecting the values to a List.

    Note that if the given parser is available implicitly, you can use the other listOf signature instead.

    This is a shortcut for Splitter.json(anyIndex).joinBy(parser).parseToList.

    The returned parser will fail if the first event is not an ArrayStart, or if any of the values inside the array cause the underlying parser to fail. E.g. if the underlying parser is JsonParser.forInt, but one of the values in the array is a string, the exception thrown by JsonParser.forInt will bubble up through the returned parser.

    E.g.

    val parser = JsonParser.listOf(JsonParser.forInt)
    parser.parse("[1, 2, 3]") // returns List(1, 2, 3)
    parser.parse("[]") // returns Nil
    parser.parse("42") // throws a SpacException
    parser.parse("[1, 2, false]") // throws a SpacException
    T

    The type of the values inside the array

    parser

    The underlying parser to use for each value inside the array

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses an array of values as a List[T]

  24. def listOf[T](implicit arg0: TypeName[T], arg1: JsonParser[T], callerPos: CallerPos): JsonParser[List[T]]

    A JsonParser that parses a JSON array by parsing each item in the array via the implicitly-available JsonParser[T], collecting the values to a List.

    A JsonParser that parses a JSON array by parsing each item in the array via the implicitly-available JsonParser[T], collecting the values to a List.

    This is a shortcut for Splitter.json(anyIndex).as[T].parseToList.

    The returned parser will fail if the first event is not an ArrayStart, or if any of the values inside the array cause the underlying parser to fail. E.g. if the underlying parser is JsonParser.forInt, but one of the values in the array is a string, the exception thrown by JsonParser.forInt will bubble up through the returned parser.

    E.g.

    val parser = JsonParser.listOf[Int]
    parser.parse("[1, 2, 3]") // returns List(1, 2, 3)
    parser.parse("[]") // returns Nil
    parser.parse("42") // throws a SpacException
    parser.parse("[1, 2, false]") // throws a SpacException
    T

    The type of the values inside the array

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses an array of values as a List[T]

  25. def nullable[T](implicit parser: JsonParser[T]): JsonParser[Option[T]]

    Wraps an existing JsonParser, creating a new JsonParser that will succeed with None if it encounters a null, or succeed with a Some(t) if the wrapped parser succeeds.

    Wraps an existing JsonParser, creating a new JsonParser that will succeed with None if it encounters a null, or succeed with a Some(t) if the wrapped parser succeeds.

    Used to parse values that may or may not be null.

    Typical usage would be JsonParser.nullable[String], passing the underlying JsonParser[String] implicitly.

    T

    The type of the underlying parser's extracted value

    parser

    The underlying parser which would typically fail upon encountering a null

    returns

    A JsonParser which parses null as None, or else delegates to the underlying parser

  26. def nullableFieldOf[T](fieldName: String, parser: JsonParser[T])(implicit arg0: TypeName[T], callerPos: CallerPos): JsonParser[Option[T]]

    A JsonParser that parses a JSON object by parsing the given optional field with the given parser.

    A JsonParser that parses a JSON object by parsing the given optional field with the given parser.

    Note that if the given parser is available implicitly, you can use the other nullableFieldOf signature.

    Unlike with fieldOf, the returned parser will succeed with a None if the expected field is missing, or if the value in the expected field is null. However, it will still fail if the first event is not an ObjectStart.

    E.g.

    val parser = JsonParser.nullableFieldOf("foo", JsonParser.forInt)
    parser.parse("{}") // returns None
    parser.parse("12") // throws a SpacException
    parser.parse("""{ "foo": 42 }""") // returns 42
    parser.parse("""{ "foo": null }""") // returns null
    parser.parse("""{ "foo": "hello" }""") // throws a SpacException
    T

    The type of the extracted value

    fieldName

    The name of the field

    parser

    The underlying parser used to parse the value inside the expected field in the object

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses the given field from a JSON object, wrapping a successfully-parsed value in Some, and treating null or a missing field as None

  27. def nullableFieldOf[T](fieldName: String)(implicit arg0: TypeName[T], arg1: JsonParser[T], callerPos: CallerPos): JsonParser[Option[T]]

    A JsonParser that parses a JSON object by parsing the given optional field with an implicitly-available JsonParser[T].

    A JsonParser that parses a JSON object by parsing the given optional field with an implicitly-available JsonParser[T].

    Unlike with fieldOf, the returned parser will succeed with a None if the expected field is missing, or if the value in the expected field is null. However, it will still fail if the first event is not an ObjectStart.

    E.g.

    val parser = JsonParser.nullableFieldOf[Int]("foo")
    parser.parse("{}") // returns None
    parser.parse(12) // throws a SpacException
    parser.parse("""{ "foo": 42 }""") // returns 42
    parser.parse("""{ "foo": null }""") // returns null
    parser.parse("""{ "foo": "hello" }""") // throws a SpacException
    T

    The type of the extracted value

    fieldName

    The name of the field

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses the given field from a JSON object, wrapping a successfully-parsed value in Some, and treating null or a missing field as None

  28. def objectOf[T](parser: JsonParser[T])(implicit arg0: TypeName[T], callerPos: CallerPos): JsonParser[Map[String, T]]

    A JsonParser that parses a JSON object by interpreting every field as a value of type T using the given parser, yielding a Map containing the parsed field -> value pairs.

    A JsonParser that parses a JSON object by interpreting every field as a value of type T using the given parser, yielding a Map containing the parsed field -> value pairs.

    Note that if the given parser is available implicitly, you can use the other objectOf signature instead.

    This is a shortcut for Splitter.json(anyField).map(field -> parser.map(field -> _)).parseToMap.

    The returned parser will fail if the first event is not an ObjectStart, or if any of the field values in the object cause the underlying parser to fail. E.g. if the underlying parser is JsonParser.forString, but one of the fields contains some non-string value, the exception thrown by JsonParser.forString will bubble up through the returned parser.

    E.g.

    val parser = JsonParser.objectOf(JsonParser.forInt)
    parser.parse("""{ "foo": 1, "bar": 2 }""") // returns Map("foo" -> 1, "bar" -> 2)
    parser.parse("""{ "foo": 1, "bar": "whoops" }""") // throws a SpacException
    parser.parse("13") // throws a SpacException
    T

    The type of the values inside each field

    parser

    The underlying parser used to parse each field in the object

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses an object as a Map[String, T]

  29. def objectOf[T](implicit arg0: TypeName[T], arg1: JsonParser[T], callerPos: CallerPos): JsonParser[Map[String, T]]

    A JsonParser that parses a JSON object by interpreting every field as a value of type T using the implicitly-available JsonParser[T], yielding a Map containing the parsed field -> value pairs.

    A JsonParser that parses a JSON object by interpreting every field as a value of type T using the implicitly-available JsonParser[T], yielding a Map containing the parsed field -> value pairs.

    This is a shortcut for Splitter.json(anyField).map(field -> implicitly[JsonParser[T]].map(field -> _)).parseToMap.

    The returned parser will fail if the first event is not an ObjectStart, or if any of the field values in the object cause the underlying parser to fail. E.g. if the underlying parser is JsonParser.forString, but one of the fields contains some non-string value, the exception thrown by JsonParser.forString will bubble up through the returned parser.

    E.g.

    val parser = JsonParser.objectOf[Int]
    parser.parse("""{ "foo": 1, "bar": 2 }""") // returns Map("foo" -> 1, "bar" -> 2)
    parser.parse("""{ "foo": 1, "bar": "whoops" }""") // throws a SpacException
    parser.parse("13") // throws a SpacException
    T

    The type of the values inside each field

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses an object as a Map[String, T]

  30. def objectOfNullable[T](parser: JsonParser[T])(implicit arg0: TypeName[T], callerPos: CallerPos): JsonParser[Map[String, T]]

    A JsonParser that parses a JSON object by interpreting every possibly-null field as a value of type T using the given JsonParser[T], filtering out null fields and yielding a Map containing field -> value pairs of the successfully-parsed fields.

    A JsonParser that parses a JSON object by interpreting every possibly-null field as a value of type T using the given JsonParser[T], filtering out null fields and yielding a Map containing field -> value pairs of the successfully-parsed fields.

    Note that if the given parser is available implicitly, you can use the other objectOfNullable signature instead.

    Note that while fields with null instead of an expected T value are filtered out, non-null fields that cause the underlying parser to fail will cause the returned parser to fail as well. As with objectOf, the returned parser will fail if the first event is not an ObjectStart.

    E.g.

    val parser = JsonParser.objectOfNullable(JsonParser.forInt)
    parser.parse("""{ "foo": 1, "bar": 2 }""") // returns Map("foo" -> 1, "bar" -> 2)
    parser.parse("""{ "foo": 1, "bar": null }""") // returns Map("foo" -> 1)
    parser.parse("""{ "foo": 1, "bar": "whoops" }""") // throws a SpacException
    parser.parse("13") // throws a SpacException
    T

    The type of the values inside each field

    parser

    The underlying parser used to parse values (aside from null) for each of the fields in the input object

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses an object as a Map[String, T], ignoring fields with null values

  31. def objectOfNullable[T](implicit arg0: TypeName[T], arg1: JsonParser[T], callerPos: CallerPos): JsonParser[Map[String, T]]

    A JsonParser that parses a JSON object by interpreting every possibly-null field as a value of type T using an implicitly-available JsonParser[T], filtering out null fields and yielding a Map containing field -> value pairs of the successfully-parsed fields.

    A JsonParser that parses a JSON object by interpreting every possibly-null field as a value of type T using an implicitly-available JsonParser[T], filtering out null fields and yielding a Map containing field -> value pairs of the successfully-parsed fields.

    Note that while fields with null instead of an expected T value are filtered out, non-null fields that cause the underlying parser to fail will cause the returned parser to fail as well. As with objectOf, the returned parser will fail if the first event is not an ObjectStart.

    E.g.

    val parser = JsonParser.objectOfNullable[Int]
    parser.parse("""{ "foo": 1, "bar": 2 }""") // returns Map("foo" -> 1, "bar" -> 2)
    parser.parse("""{ "foo": 1, "bar": null }""") // returns Map("foo" -> 1)
    parser.parse("""{ "foo": 1, "bar": "whoops" }""") // throws a SpacException
    parser.parse("13") // throws a SpacException
    T

    The type of the values inside each field

    callerPos

    Macro-derived location of the code calling this method, used to form a SpacTraceElement when the returned parser fails

    returns

    A JsonParser that parses an object as a Map[String, T], ignoring fields with null values

  32. def toString(): String
    Definition Classes
    Any

Deprecated Value Members

  1. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from JsonParserApplyOps toStringFormat[JsonParserApplyOps] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @deprecated @inline()
    Deprecated

    (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), or use the f"" string interpolator. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters.

  2. def [B](y: B): (JsonParserApplyOps, B)
    Implicit
    This member is added by an implicit conversion from JsonParserApplyOps toArrowAssoc[JsonParserApplyOps] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) Use -> instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

Inherited from AnyVal

Inherited from Any

Inherited by implicit conversion any2stringadd fromJsonParserApplyOps to any2stringadd[JsonParserApplyOps]

Inherited by implicit conversion StringFormat fromJsonParserApplyOps to StringFormat[JsonParserApplyOps]

Inherited by implicit conversion Ensuring fromJsonParserApplyOps to Ensuring[JsonParserApplyOps]

Inherited by implicit conversion ArrowAssoc fromJsonParserApplyOps to ArrowAssoc[JsonParserApplyOps]

Objects and Arrays

Primitives

Ungrouped