shape factory baby

lib/main.dart

@@ -20,49 +20,32 @@ class MyApp extends StatelessWidget {
   }
 }
 
-abstract class ListStrategy<T> {
-  List<T> compose(List<T> items);
+abstract class ShapeFactory {
+  Widget build(Size size, Color color);
 }
 
-class Monkey {
-  Monkey({required this.name, required this.power});
-  final String name;
-  final int power;
-
+class SquareFactory extends ShapeFactory {
   @override
-  String toString() => '$name - Power: $power';
-}
-
-class GreatestMonkeyStrategy implements ListStrategy<Monkey> {
-  @override
-  List<Monkey> compose(List<Monkey> items) {
-    return [
-      items.fold<Monkey>(
-          Monkey(name: '', power: 0), (aMonkey, bMonkey) => aMonkey.power > bMonkey.power ? aMonkey : bMonkey)
-    ];
+  Widget build(Size size, Color color) {
+    return SizedBox.fromSize(
+      size: size,
+      child: Container(color: color),
+    );
   }
 }
 
-class WeakMonkeysStrategy implements ListStrategy<Monkey> {
+class CircleFactory extends ShapeFactory {
   @override
-  List<Monkey> compose(List<Monkey> items) {
-    return items
-        .where(
-          (element) => element.power <= 200,
-        )
-        .toList();
+  Widget build(Size size, Color color) {
+    return SizedBox.fromSize(
+      size: size,
+      child: Container(
+        decoration: BoxDecoration(shape: BoxShape.circle, color: color),
+      ),
+    );
   }
 }
 
-List<Monkey> monkeys = [
-  Monkey(name: 'Mortimer', power: 25),
-  Monkey(name: 'ApeMan', power: 354),
-  Monkey(name: 'Spider', power: 65),
-  Monkey(name: 'DK', power: 500),
-  Monkey(name: 'Tim', power: 120),
-  Monkey(name: 'Kong', power: 25400),
-];
-
 class MyHomePage extends StatefulWidget {
   const MyHomePage({super.key});
 
@@ -71,14 +54,16 @@ class MyHomePage extends StatefulWidget {
 }
 
 class _MyHomePageState extends State<MyHomePage> {
-  ListStrategy listStrat = WeakMonkeysStrategy();
+  final List<ShapeFactory> shapeFactories = [CircleFactory(), SquareFactory()];
+  int factoryIndex = 0;
+  ShapeFactory get factory => shapeFactories[factoryIndex];
 
-  void swapStrategies() {
-    if (listStrat.runtimeType == WeakMonkeysStrategy) {
-      setState(() => listStrat = GreatestMonkeyStrategy());
+  void swapFactories() {
+    if (factoryIndex == 0) {
+      setState(() => factoryIndex = 1);
       return;
     }
-    setState(() => listStrat = WeakMonkeysStrategy());
+    setState(() => factoryIndex = 0);
   }
 
   @override
@@ -92,22 +77,18 @@ class _MyHomePageState extends State<MyHomePage> {
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
-            const Text('All monkeys:'),
-            ...monkeys
-                .map(
-                  (e) => Text(e.toString()),
-                )
-                .toList(),
-            const SizedBox(height: 50),
-            Text(listStrat.runtimeType.toString()),
-            ...listStrat
-                .compose(monkeys)
-                .map(
-                  (e) => Text(e.toString()),
-                )
-                .toList(),
-            const SizedBox(height: 100),
-            ElevatedButton(onPressed: () => swapStrategies(), child: const Text('Change Strats')),
+            const Text('Abstract Factories!!'),
+            Text('Using ${shapeFactories[factoryIndex].runtimeType.toString()}'),
+            ...List.generate(
+                3,
+                (index) => factory.build(
+                      Size(20.0 * (index + 1), 30.0 * (index + 1)),
+                      [Colors.red, Colors.green, Colors.blue][index],
+                    )),
+            ElevatedButton(
+              onPressed: () => swapFactories(),
+              child: const Text('Swap Factories'),
+            ),
           ],
         ),
       ),