Add iterator pattern.

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 0.36.0
+- Add iterator pattern: Github Commit.
+
 ## 0.35.0
 - Add conceptual command pattern.
 

README.md

@@ -13,7 +13,7 @@ It contains **Dart** examples for all classic **GoF** design patterns.
     - [x] **Chain of Responsibility** - [[Server Middleware](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/chain_of_responsibility/server_middleware)]
     - [x] **Command** - [[Conceptual](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/command/conceptual)] [[Text Editor](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/command/text_editor)] 
     - [x] **Interpreter**  - [[Conceptual](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/interpreter/conceptual)]
-    - [ ] **Iterator**
+    - [x] **Iterator** - [[Github Commit](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/iterator/github_commit)]
     - [x] **Mediator** - [[Conceptual](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/mediator/conceptual)]
     - [x] **Memento** - [[Conceptual](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/memento/conceptual)] [[![16x16](https://user-images.githubusercontent.com/8049534/171852337-57db0faf-1f5e-489a-a79a-22ed4f47b4ed.png) Memento Editor](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/memento/memento_editor)] 
     - [x] **Observer** - [[Open-Close Editor Events](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/open_close_editor_events)] [[AppObserver](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/app_observer)] [[![16x16](https://user-images.githubusercontent.com/8049534/171852337-57db0faf-1f5e-489a-a79a-22ed4f47b4ed.png) Subscriber Flutter Widget](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/subscriber_flutter_widget)]

patterns/iterator/github_commit/README.md

@@ -0,0 +1,44 @@
+# Template Method Pattern
+Iterator is a behavioral design pattern that lets you traverse elements of a collection without 
+exposing its underlying representation (list, stack, tree, etc.).
+
+Tutorial: [here](https://refactoring.guru/design-patterns/iterator).
+
+## Diagram:
+![image](https://user-images.githubusercontent.com/8049534/183165928-7274e761-09e3-48ce-b9c1-41d552fa1f1a.png)
+
+
+### Client code:
+```dart
+void main() async {
+  final GitHubRepo gitHubRepo = await GitHubLoader.get(
+    userName: 'RefactoringGuru',
+    repoName: 'design-patterns-dart',
+  );
+
+  print(
+    'Iterate last 10 commits.'
+        '\n----------------------------',
+  );
+
+  for (Commit commit in gitHubRepo.commitIterator()) {
+    print(commit.message);
+  }
+}
+```
+
+### Output:
+```
+Iterate last 10 commits.
+----------------------------
+Merge pull request #74 from ilopX/fix-conceptual-command-pattern-folder-name Fix conceptual command pattern folder name
+Fix conceptual command pattern folder name.
+Merge pull request #73 from ilopX/add-conceptual-command-pattern Add conceptual command pattern
+Bump version 0.35.0.
+Add README.
+Impl conceptual command pattern.
+Merge pull request #72 from ilopX/add-singleton-pattern Add singleton pattern.
+Bump version 0.34.0.
+Add README.
+```
+

patterns/iterator/github_commit/github/commit.dart

@@ -0,0 +1,5 @@
+class Commit {
+  String message;
+
+  Commit(this.message);
+}

patterns/iterator/github_commit/github/github_loader.dart

@@ -0,0 +1,27 @@
+import 'dart:convert';
+import 'dart:io';
+import '../pattern/github_repo.dart';
+
+class GitHubLoader {
+  static Future<GitHubRepo> get({required userName, required repoName}) async {
+    final url = Uri.http(
+      'api.github.com',
+      'repos/$userName/$repoName/commits',
+      {'per_page': '10'},
+    );
+    final json = await _loadCommits(url);
+    return GitHubRepo(json);
+  }
+
+  static Future<List<dynamic>> _loadCommits(Uri url) async {
+    final client = HttpClient();
+    try {
+      final response = await client.getUrl(url);
+      final request = await response.close();
+      final content = await request.transform(utf8.decoder).join();
+      return jsonDecode(content);
+    } finally {
+      client.close();
+    }
+  }
+}

patterns/iterator/github_commit/main.dart

@@ -0,0 +1,19 @@
+import 'github/commit.dart';
+import 'github/github_loader.dart';
+import 'pattern/github_repo.dart';
+
+void main() async {
+  final GitHubRepo gitHubRepo = await GitHubLoader.get(
+    userName: 'RefactoringGuru',
+    repoName: 'design-patterns-dart',
+  );
+
+  print(
+    'Iterate last 10 commits.'
+    '\n----------------------------',
+  );
+
+  for (Commit commit in gitHubRepo.commitIterator()) {
+    print(commit.message);
+  }
+}

patterns/iterator/github_commit/pattern/github_repo.dart

@@ -0,0 +1,16 @@
+import '../github/commit.dart';
+
+class GitHubRepo {
+  GitHubRepo(this._json);
+
+  Iterable<Commit> commitIterator() sync* {
+    for (final jsonCommit in _json) {
+      var message = jsonCommit['commit']['message'] as String;
+      message = message.replaceAll(RegExp(r'\n+'), ' ');
+
+      yield Commit(message);
+    }
+  }
+
+  final List<dynamic> _json;
+}

pubspec.yaml

@@ -1,6 +1,6 @@
 name: design_patterns_dart
 description: Dart examples for all classic GoF design patterns.
-version: 0.35.0
+version: 0.36.0
 homepage: https://refactoring.guru/design-patterns
 repository: https://github.com/RefactoringGuru/design-patterns-dart
 issue_tracker: https://github.com/RefactoringGuru/design-patterns-dart/issue