Package dev.frostlake.values

Class VariantOrder

java.lang.Object
dev.frostlake.values.VariantOrder
public final class VariantOrder extends Object
How two VARIANT values order and compare, live-verified member by member.

The KIND decides first: BOOLEAN < NUMBER < STRING < OBJECT < ARRAY < JSON null (with an array's undefined hole after the null, so [1,undefined] and [1,null] stay unequal). Within a kind: false before true; numbers by VALUE whatever their notation (10 after 9, 1 equal to 1.0 and 1e0), with -Infinity below every finite number and NaN above Infinity; strings by their code points ("10" before "9", "Z" before "a"); arrays element by element in this same order, a prefix first ([] < [0,5] < [1] < [1,2] < ["a"]); objects member by member over their keys in sorted order, where at each position the LARGER key sorts first and equal keys compare their values, a prefix first ({} < {"b":0} < {"a":0} < {"a":0,"c":0} < {"a":0,"b":0} < {"a":0,"b":1} < {"a":1,"b":0}); a JSON null equals a JSON null. Equality is this comparison answering zero, so {"a":1,"b":2} equals {"b":2,"a":1} and [1] equals [1.0], while a variant STRING never equals the number or object it spells.

  • Method Details

    • compare

      public static int compare(tools.jackson.databind.JsonNode left, tools.jackson.databind.JsonNode right)
      Orders two members.
      Parameters:
      left - one member, null read as a JSON null
      right - the other
      Returns:
      negative, zero or positive

    • comparisonKey

      public static String comparisonKey(tools.jackson.databind.JsonNode node)
      A text that is the same for two members exactly when compare(tools.jackson.databind.JsonNode, tools.jackson.databind.JsonNode) answers zero — the key equality and hashing use, so a DISTINCT, a GROUP BY or a set operation sees 1 and 1.0 as one value and {"a":1,"b":2} and {"b":2,"a":1} as one object.
      Parameters:
      node - the member
      Returns:
      its key