Interface JsonFactory<N>

Type Parameters:
N - the node type of the caller's JSON representation
All Known Implementing Classes:
JacksonJsonModel
public interface JsonFactory<N>

Builds nodes of the caller's JSON representation.

A JsonModel gives read access, and it is enough for all standard functions of RFC 9535. A model that also implements JsonFactory can run function extensions that make new values, for example a function that returns a new array. A read-only model, for example a model over a memory-mapped file, does not implement this interface.

Contract

  • No exceptions. No method throws an exception.
  • Exact values. For a node that a method builds, the read methods of the model give the same value again. For example, JsonModel.numberValue(Object) of number(x) has the same exact value as x, and JsonModel.kind(Object) of bool(true) is JsonKind.TRUE.
  • New nodes. A built node is not part of the query argument, so it has no location.

jsonlens calls object(List) only with unique member names. A function extension must do the same.

  • Method Details

    • string

      N string(JsonString value)
      Builds a string.
      Parameters:
      value - the value
      Returns:
      a node of kind JsonKind.STRING

    • number

      Maybe<N> number(JsonNumber value)

      Builds a number.

      A representation can have a limit. For example, a BigDecimal cannot hold a number with an exponent outside the range of int. Then the result is Maybe.None: the factory never builds a number with a different value.

      Parameters:
      value - the value
      Returns:
      a node of kind JsonKind.NUMBER with the exact value, or Maybe.None if the representation cannot hold the value

    • bool

      N bool(boolean value)
      Builds true or false.
      Parameters:
      value - the value
      Returns:
      a node of kind JsonKind.TRUE or JsonKind.FALSE

    • nullValue

      N nullValue()
      Builds null.
      Returns:
      a node of kind JsonKind.NULL

    • array

      N array(List<N> elements)
      Builds an array.
      Parameters:
      elements - the elements, in order
      Returns:
      a node of kind JsonKind.ARRAY

    • object

      N object(List<Property<N>> members)
      Builds an object.
      Parameters:
      members - the members, in order. The names are unique.
      Returns:
      a node of kind JsonKind.OBJECT

    • copyOf

      default <S> Maybe<N> copyOf(JsonModel<S> model, S value)

      Builds a deep copy of a value of any model, in the representation of this factory.

      The source can be a value of another JSON library, for example a value of a memory-mapped file copied into a Jackson tree. It can also be a value of this model: then the copy shares no node with the source, so a later change of the copy does not change the source. Strings and numbers go to string(JsonString) and number(JsonNumber) in the representation of the source, so the factory decides if it must convert them.

      The method uses no recursion, so a deep value cannot overflow the stack. It never gives duplicate member names to object(List): the copy of an object with duplicate names (see JsonModel.hasDuplicate(Object, JsonString)) fails, because its value is not defined (RFC 8259, Section 4).

      Type Parameters:
      S - the node type of the source model
      Parameters:
      model - the model of the source value
      value - the source value
      Returns:
      the copy, or Maybe.None if this representation cannot hold a number of the value, or if an object of the value has duplicate member names, or if the source model is not well-formed (it gives no element below the length of an array)