add simplified token algorithm

Modules/Example Replication/jvm/src/main/scala/replication/papoctokens/Tokens.scala

@@ -0,0 +1,61 @@
+package replication.papoctokens
+
+import kofre.base.{Bottom, Lattice, Uid}
+import kofre.datatypes.contextual.ReplicatedSet
+import kofre.datatypes.contextual.ReplicatedSet.syntax
+import kofre.datatypes.experiments.RaftState
+import kofre.dotted.Dotted
+import kofre.syntax.{DeltaBuffer, OpsSyntaxHelper, ReplicaId}
+
+import scala.util.Random
+
+case class Token(epoche: Long, owner: Uid)
+
+object Token {
+  given Lattice[Token] = Lattice.fromOrdering(Ordering.by(_.epoche))
+
+  given bottom: Bottom[Token] = Bottom.provide(Token(Long.MinValue, Uid.zero))
+
+  def unchanged: Token = bottom.empty
+}
+
+case class TokenAgreement(
+    token: Token,
+    wants: ReplicatedSet[Uid]
+)
+object TokenAgreement {
+
+  val unchanged: Dotted[TokenAgreement] = Dotted(TokenAgreement(Token.unchanged, ReplicatedSet.empty))
+
+  extension [C, E](container: C)
+    def tokens: syntax[C] = syntax(container)
+
+  implicit class syntax[C](container: C) extends OpsSyntaxHelper[C, TokenAgreement](container) {
+
+    def updateWant(f: Dotted[ReplicatedSet[Uid]] => Dotted[ReplicatedSet[Uid]]): CausalMutate = mutate:
+      val addWant: Dotted[ReplicatedSet[Uid]] = f(current.wants.inheritContext)
+
+      addWant.map: aw =>
+        TokenAgreement(Token.unchanged, aw)
+
+    def request(using ReplicaId): CausalMutate = updateWant(_.add(replicaId))
+
+    def release(using ReplicaId): CausalMutate = updateWant(_.remove(replicaId))
+
+    def grant(using ReplicaId): CausalMutate = mutate:
+      // We finde the “largest” ID that wants the token.
+      // This is incredibly “unfair” but does prevent deadlocks in case someone needs multiple tokens.
+      current.wants.elements.maxOption match
+        case Some(head) if head != replicaId =>
+          val removeWant: Dotted[ReplicatedSet[Uid]] = current.wants.inheritContext.remove(head)
+          removeWant.map: rw =>
+            TokenAgreement(Token(current.token.epoche + 1, head), rw)
+        case _ => unchanged
+
+  }
+}
+
+case class ExampleTokens(
+    calendarA: TokenAgreement,
+    calendarB: TokenAgreement
+)