js1972 · January 5, 2014 05:42 · Mar 8, 2014 · Jan 15, 2013 · Jan 15, 2013
diff --git a/di-value-injection-warmer b/di-value-injection-warmer
@@ -35,7 +35,7 @@
   // instantiate the services in a configuration module
   object Context {
     // this is where injection happens
-    lazy val warmer = new Warmer {
+    val warmer = new Warmer {
       val potSensor = new PotSensor
       val heater = new Heater
     }

diff --git a/di-value-injection-warmer b/di-value-injection-warmer
@@ -0,0 +1,44 @@
+  // =======================
+  // service interfaces
+  trait OnOffDevice {
+    def on: Unit
+    def off: Unit
+  }
+  trait SensorDevice {
+    def isCoffeePresent: Boolean
+  }
+
+  // =======================
+  // service implementations
+  class Heater extends OnOffDevice {
+    def on = println("heater.on")
+    def off = println("heater.off")
+  }
+  class PotSensor extends SensorDevice {
+    def isCoffeePresent = true
+  }
+
+  // =======================
+  // service declaring two dependencies that it wants injected,
+  // is using value injection to declare its dependencies
+  trait Warmer {
+    val potSensor: SensorDevice
+    val heater: OnOffDevice
+
+    def trigger = {
+      if (potSensor.isCoffeePresent) heater.on
+      else heater.off
+    }
+  }
+
+  // =======================
+  // instantiate the services in a configuration module
+  object Context {
+    // this is where injection happens
+    lazy val warmer = new Warmer {
+      val potSensor = new PotSensor
+      val heater = new Heater
+    }
+  }
+
+  Context.warmer.trigger