#1 Added caching of shape types.

build.sbt

@@ -16,6 +16,8 @@ libraryDependencies ++= Seq(
   "org.apache.tinkerpop" % "tinkergraph-gremlin" % "3.3.0",
   //TODO: "com.github.mdr" %% "ascii-graphs" % "0.0.3", pending 2.12
   "com.indvd00m.ascii.render" % "ascii-render"        % "1.2.1", //used instead of above^
+  "com.github.cb372" %% "scalacache-core" % "0.22.0",
+  "com.github.cb372" %% "scalacache-caffeine" % "0.22.0",
   "org.scala-lang.modules"    %% "scala-java8-compat" % "0.8.0",
   "org.scala-lang"            % "scala-reflect"      % scalaVersion.value,
   "org.log4s"                 %% "log4s"              % "1.4.0"

src/main/scala/net/mikolak/travesty/Registry.scala

@@ -3,8 +3,25 @@ package net.mikolak.travesty
 import akka.stream.{Graph, Shape}
 
 import scala.reflect.runtime.universe._
+import scalacache.Id
 
 object Registry {
+  import scalacache.Cache
+  import scalacache.modes.sync._
+  import scalacache.caffeine._
+  import scala.concurrent.duration._
+  import language.postfixOps
+
+  private val cache: Cache[ShapeTypes] = CaffeineCache[ShapeTypes]
+
+  def register[T <: Graph[_ <: Shape, _]: TypeTag](g: T): T = {
+    val shapeTypes = deconstructShape(g)
+    cache.put(g)(shapeTypes, ttl = Some(5 minutes)) //TODO: move to config
+    g
+  }
+
+  def lookup(g: Graph[_ <: Shape, _]): Id[Option[ShapeTypes]] = cache.get(g)
+
   private[travesty] def deconstructShape[T <: Graph[_ <: Shape, _]: TypeTag](g: T): ShapeTypes = {
     val tpe             = typeOf[T]
     val graphType       = tpe.baseType(typeOf[Graph[_, _]].typeSymbol)

src/test/scala/net/mikolak/travesty/RegistrySpec.scala

@@ -45,6 +45,35 @@ class RegistrySpec extends FlatSpec with MustMatchers with MustVerb with TableDr
       tested(Flow[A].mapAsync(3)(a => Future.successful(a.toB)).async) must be(ShapeTypes(List(typeOf[A]), List(typeOf[B])))
     }
   }
+
+  {
+    def when[T <: Graph[_ <: Shape, _]: TypeTag](g: T) = Registry.register(g)
+
+    "register" must "remember shape immediately after saving" in {
+      val s = Source.single("t")
+
+      when(s)
+
+      Registry.lookup(s) must be a 'nonEmpty
+    }
+
+    it must "not remember a non-saved shape" in {
+      val s = Source.single("t")
+
+      Registry.lookup(s) must be an 'empty
+    }
+
+    it must "remember a shape after a short time" in {
+      val s = Flow[B].map(identity)
+
+      when(s)
+
+      Thread.sleep(100)
+
+      Registry.lookup(s) must be a 'nonEmpty
+    }
+
+  }
 }
 
 trait A {