MVMap

A delta-based CRDT map implementing multi-value (MV) policy.

Each entry behaves like a MVRegister: values written concurrently are all kept until a write replaces them; accessors return the set of current values. A write (or delete) replaces every visible (local or merged) value.

On merging, for each key, a value is kept iff either:

• it is in both replicas/deltas, or

• it is in one replica and its associated timestamp is not in the causal context of the other replica.

Its JSON serialization respects the following schema:

{
  "type": "MVMap",
  "metadata": {
      "entries": {
          // $key is a string
          (( "$key": [ ( Timestamp.toJson() )*( , Timestamp.toJson() )? ] )*( , "$key": [ ( Timestamp.toJson() )*( , Timestamp.toJson() )? ] ))?
      },
      "causalContext": VersionVector.toJson()
  }
  // $key is a string and $value can be a Boolean, Double, Int or String
  ( , "$key": [
          (( T.toJson(), )*( T.toJson() ))?
  ] )*
}