Time for an 2014 update…

Task/Abstract-type/ActionScript/abstract-type-2.as

@@ -0,0 +1,22 @@
+package {
+    import flash.utils.getQualifiedClassName;
+
+    public class AbstractClass {
+
+        private static const FULLY_QUALIFIED_NAME:String = "AbstractClass";
+
+        // For classes in a package, the fully qualified name should be in the form "package.name::class_name"
+        // Note that a double colon and not a dot is used before the class name. This is the format returned
+        // by the getQualifiedClassName() function.
+
+        public function AbstractClass() {
+            if ( getQualifiedClassName(this) == FULLY_QUALIFIED_NAME )
+                throw new Error("Class " + FULLY_QUALIFIED_NAME + " is abstract.");
+        }
+
+        public function abstractMethod(a:int, b:int):void {
+            throw new Error("abstractMethod is not implemented.");
+        }
+
+    }
+}

Task/Abstract-type/ActionScript/abstract-type-3.as

@@ -0,0 +1,10 @@
+package {
+
+    public class Example extends AbstractClass {
+
+        override public function abstractMethod(a:int, b:int):void {
+            trace(a + b);
+        }
+
+    }
+}