Packages

  • package root

    JSON (JavaScript Object Notation) is a lightweight data-interchange format.

    JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for machines to parse and generate. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages,

    JSON has only types of string, number, boolean, object, array, and null. This library includes additional types such as date, int, long, double, counter, binary, UUID, ObjectId (as in BSON), etc.

    It is very easy to parse a JSON object:

    val doc =
      json"""
      {
        "store": {
          "book": [
            {
              "category": "reference",
              "author": "Nigel Rees",
              "title": "Sayings of the Century",
              "price": 8.95
            },
            {
              "category": "fiction",
              "author": "Evelyn Waugh",
              "title": "Sword of Honour",
              "price": 12.99
            },
            {
              "category": "fiction",
              "author": "Herman Melville",
              "title": "Moby Dick",
              "isbn": "0-553-21311-3",
              "price": 8.99
            },
            {
              "category": "fiction",
              "author": "J. R. R. Tolkien",
              "title": "The Lord of the Rings",
              "isbn": "0-395-19395-8",
              "price": 22.99
            }
          ],
          "bicycle": {
            "color": "red",
            "price": 19.95
          }
        }
      }
      """

    The interpolator json parse a string to JsObject. To parse an array, use the interpolator jsan to JsArray. It is also okay to embed variable references directly in processed string literals.

    val x = 1
    json"""
      {
        "x": $x
      }
    """

    If the string is not a JSON object but any other valid JSON expression, one may use parseJson method to convert the string to a JsValue.

    "1".parseJson

    The json interpolator can only be applied to string literals. If you want to parse a string variable, the parseJson method can always be employed. If you know the string contains a JSON object, you may also use the method parseJsObject.

    val s = """{"x":1}"""
    s.parseJsObject

    To serialize a JSON value (of type JsValue) in compact mode, you can just use toString. To pretty print, use the method prettyPrint.

    doc.toString
    doc.prettyPrint

    With a JsObject or JsArray, you can refer to the individual elements with a variation of array syntax, like this:

    doc("store")("bicycle")("color")
    doc("store")("book")(0)("author")

    Note that we follow Scala's array access convention by () rather than [] in JavaScript.

    Besides, you can use the dot notation to access its fields/elements just like in JavaScript:

    doc.store.bicycle.color
    doc.store.book(0).author

    It is worth noting that we didn't define the type/schema of the document while Scala is a strong type language. In other words, we have both the type safe features of strong type language and the flexibility of dynamic language in this JSON library.

    If you try to access a non-exist field, JsUndefined is returned.

    scala> doc.book
    res11: unicorn.json.JsValue = undefined

    Although there are already several nice JSON libraries for Scala, the JSON objects are immutable by design, which is a natural choice for a functional language. For database, however, data mutation is necessary. Therefore, JsObject and JsArray are mutable data structures. You can set/add a field just like in JavaScript:

    json.store.bicycle.color = "green"

    To delete a field from JsObject, use remove method:

    doc.store.book(0) remove "price"

    It is same as setting it JsUndefined:

    doc.store.book(0).price = `JsUndefined`

    To delete an element from JsArray, the remove method will effectively remove it from the array. However, setting an element to undefined doesn't reduce the array size.

    // delete the first element and array size is smaller
    doc.store.book.remove(0)
    // set the first element to undefined but array size keeps same
    doc.store.book(0) = JsUndefined

    It is also possible to append an element or another array to JsArray:

    val a = JsArray(1, 2, 3, 4)
    a += 5
    
    a ++= JsArray(5, 6)

    Common iterative operations such as foreach, map, reduce can be applied to JsArray too.

    doc.store.book.asInstanceOf[JsArray].foreach { book =>
     println(book.price)
    }

    Because Scala is a static language, it is impossible to know doc.store.book is an array at compile time. So it is typed as generic JsValue, which is the parent type of specific JSON data types. Therefore, we use asInstanceOf[JsArray] to convert it to JsArray in order to use foreach.

    Definition Classes
    root
  • package smile
    Definition Classes
    root
  • package json

    Definition Classes
    smile
  • CompactPrinter
  • JsArray
  • JsBinary
  • JsBoolean
  • JsCounter
  • JsDate
  • JsDateTime
  • JsDecimal
  • JsDouble
  • JsInt
  • JsLong
  • JsNull
  • JsObject
  • JsObjectId
  • JsString
  • JsTime
  • JsTimestamp
  • JsUUID
  • JsUndefined
  • JsValue
  • JsValueOrdering
  • JsonHelper
  • JsonParser
  • JsonPrinter
  • JsonSerializer
  • ObjectId
  • ParserInput
  • PrettyPrinter

class JsonSerializer extends LazyLogging

JSON Serializer in BSON format as defined by http://bsonspec.org/spec.html. This is not fully compatible with BSON spec, where the root must be a document/JsObject. In contrast, the root can be any JsValue in our implementation. Correspondingly, the root will always has the type byte as the first byte.

Not Multi-threading safe. Each thread should have its own BsonSerializer instance. Data size limit to 10MB by default.

Although JsTime/JsDateTime can be represented to nanosecond precision, we don't store the nano-of-second field to save the space. To preserve the high precision of time, JsTimestamp should be employed and of course consumes more space.

Linear Supertypes
LazyLogging, AnyRef, Any
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Inherited
  1. JsonSerializer
  2. LazyLogging
  3. AnyRef
  4. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
  1. Hide All
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Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new JsonSerializer(buffer: ByteBuffer = ByteBuffer.allocate(10 * 1024 * 1024))

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from JsonSerializer toany2stringadd[JsonSerializer] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (JsonSerializer, B)
    Implicit
    This member is added by an implicit conversion from JsonSerializer toArrowAssoc[JsonSerializer] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  7. def clear(): Unit

    Clears the object buffer.

  8. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  9. def deserialize(buffer: ByteBuffer): JsValue
  10. def deserialize(bytes: Array[Byte]): JsValue
  11. def ensuring(cond: (JsonSerializer) => Boolean, msg: => Any): JsonSerializer
    Implicit
    This member is added by an implicit conversion from JsonSerializer toEnsuring[JsonSerializer] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: (JsonSerializer) => Boolean): JsonSerializer
    Implicit
    This member is added by an implicit conversion from JsonSerializer toEnsuring[JsonSerializer] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. def ensuring(cond: Boolean, msg: => Any): JsonSerializer
    Implicit
    This member is added by an implicit conversion from JsonSerializer toEnsuring[JsonSerializer] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  14. def ensuring(cond: Boolean): JsonSerializer
    Implicit
    This member is added by an implicit conversion from JsonSerializer toEnsuring[JsonSerializer] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  15. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  16. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  17. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  18. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  19. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  20. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  21. lazy val logger: Logger
    Attributes
    protected
    Definition Classes
    LazyLogging
    Annotations
    @transient()
  22. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  23. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  24. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  25. def serialize(json: JsValue): Array[Byte]
  26. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  27. def toString(): String
    Definition Classes
    AnyRef → Any
  28. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  29. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  30. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()

Deprecated Value Members

  1. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from JsonSerializer toStringFormat[JsonSerializer] 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): (JsonSerializer, B)
    Implicit
    This member is added by an implicit conversion from JsonSerializer toArrowAssoc[JsonSerializer] 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 LazyLogging

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd fromJsonSerializer to any2stringadd[JsonSerializer]

Inherited by implicit conversion StringFormat fromJsonSerializer to StringFormat[JsonSerializer]

Inherited by implicit conversion Ensuring fromJsonSerializer to Ensuring[JsonSerializer]

Inherited by implicit conversion ArrowAssoc fromJsonSerializer to ArrowAssoc[JsonSerializer]

Ungrouped