Data commit

Task/Delegates/Scala/delegates.scala

@@ -0,0 +1,32 @@
+trait Thingable {
+  def thing: String
+}
+
+class Delegator {
+  var delegate: Thingable = _
+
+  def operation: String = if (delegate == null) "default implementation"
+  else delegate.thing
+}
+
+class Delegate extends Thingable {
+  override def thing = "delegate implementation"
+}
+
+// Example usage
+// Memory management ignored for simplification
+object DelegateExample extends App {
+
+  val a = new Delegator
+  assert(a.operation == "default implementation")
+  // With a delegate:
+  val d = new Delegate
+  a.delegate = d
+  assert(a.operation == "delegate implementation")
+  // Same as the above, but with an anonymous class:
+  a.delegate = new Thingable() {
+    override def thing = "anonymous delegate implementation"
+  }
+  assert(a.operation == "anonymous delegate implementation")
+
+}