Updates for Reactive synchronize support

Author: darkfrog26

build.sbt

@@ -5,15 +5,15 @@ val scala213 = "2.13.18"
 
 val scala212 = "2.12.21"
 
-val scala3 = List("3.3.7")
+val scala3 = "3.3.7"
 
 val scala2 = List(scala213, scala212)
-val allScalaVersions = scala2 ::: scala3
+val allScalaVersions = scala3 :: scala2
 
 ThisBuild / name := "reactify"
 ThisBuild / organization := "com.outr"
-ThisBuild / version := "4.1.6-SNAPSHOT"
-ThisBuild / scalaVersion := scala213
+ThisBuild / version := "4.2.0-SNAPSHOT"
+ThisBuild / scalaVersion := scala3
 ThisBuild / crossScalaVersions := allScalaVersions
 
 ThisBuild / sonatypeCredentialHost := Sonatype.sonatypeCentralHost

reactify/src/main/scala/reactify/Reactive.scala

@@ -1,12 +1,9 @@
 package reactify
 
-import java.util.{Timer, TimerTask}
-
 import reactify.reaction.{Reaction, ReactionStatus, Reactions}
 
 import scala.annotation.tailrec
-import scala.concurrent.duration.FiniteDuration
-import scala.concurrent.{Future, Promise, TimeoutException}
+import scala.concurrent.{Future, Promise}
 
 /**
   * Reactive is the core trait for Reactify. The basic premise is that a Reactive represents an instance that can attach
@@ -19,6 +16,11 @@ trait Reactive[T] {
     override def initialValue(): Option[ReactionStatus] = None
   }
 
+  /**
+   * If true, events that are fired are synchronized to avoid concurrent invocations. Defaults to false.
+   */
+  protected def synchronize: Boolean = false
+
   /**
     * If the current thread is reacting to a value currently, status represents the status of the reaction. This can be
     * set to ReactionStatus.Stop in order to stop propagation. This can also be achieved via stopPropagation().
@@ -105,10 +107,16 @@ trait Reactive[T] {
     promise.future
   }
 
+  private def doFire(f: => ReactionStatus): ReactionStatus = if (synchronize) {
+    synchronized(f)
+  } else {
+    f
+  }
+
   /**
     * Fires the value to the Reactions
     */
-  protected def fire(value: T, previous: Option[T], reactions: List[Reaction[T]] = this.reactions()): ReactionStatus = {
+  protected def fire(value: T, previous: Option[T], reactions: List[Reaction[T]] = this.reactions()): ReactionStatus = doFire {
     _status.set(Some(ReactionStatus.Continue))
     try {
       fireInternal(value, previous, reactions)