实现迭代器模式示例，添加任务结构体、迭代器接口及具体实现，增强代码可读性

2026-01-06 02:03:46 +08:00
parent cc215c9d70
commit f579b1a5cc
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+"""
+实例：
+汤宝宝有一张TODO表，记录着自己想干的事情。
+"""
+
+from abc import ABC, abstractmethod
+
+
+# 任务结构体 - 迭代器元素
+class Todo:
+    content: str
+    done: bool
+
+    def __init__(self, content: str, done: bool = False):
+        self.content = content
+        self.done = done
+
+
+# 集合接口
+class Collection(ABC):
+    @abstractmethod
+    def CreateIterator(self) -> "Iterator":
+        pass
+
+
+# 具体集合 - 汤宝宝的TODO表
+class TodoList(Collection):
+    todos: list[Todo]
+
+    def __init__(self, todos: list[Todo]):
+        self.todos = todos
+
+    def CreateIterator(self) -> "Iterator":
+        return TodoListIterator(self)
+
+
+# 迭代器接口
+class Iterator(ABC):
+    @abstractmethod
+    def First(self) -> Todo:
+        pass
+
+    @abstractmethod
+    def Next(self) -> Todo | None:
+        pass
+
+    @abstractmethod
+    def isDone(self) -> bool:
+        pass
+
+    @abstractmethod
+    def CurrentItem(self) -> int:
+        pass
+
+
+# 具体迭代器 - 汤宝宝的TODO表迭代器
+class TodoListIterator(Iterator):
+    def __init__(self, todo_list: "TodoList"):
+        self._todo_list = todo_list
+        self._current = 0
+
+    def First(self) -> Todo:
+        self._current = 0
+        return self._todo_list.todos[self._current]
+
+    def Next(self) -> Todo | None:
+        self._current += 1
+        if not self.isDone():
+            return self._todo_list.todos[self._current]
+        return None
+
+    def isDone(self) -> bool:
+        return self._current >= len(self._todo_list.todos)
+
+    def CurrentItem(self) -> int:
+        if self.isDone():
+            return len(self._todo_list.todos)
+        return self._current + 1
+
+
+if __name__ == "__main__":
+    print("============= 迭代器模式 =============")
+
+    # 创建TODO表并添加任务
+    todo_list = TodoList(
+        todos=[
+            Todo("学习Go语言", True),
+            Todo("完成设计模式作业", False),
+            Todo("锻炼身体", False),
+        ]
+    )
+
+    # 创建迭代器
+    iterator = todo_list.CreateIterator()
+
+    # 使用迭代器遍历TODO表
+    item = iterator.First()
+    while not iterator.isDone():
+        done = "已完成" if item and item.done else "未完成"
+        print(
+            f"当前第 {iterator.CurrentItem()} 项任务内容: {item.content if item else ''} 是否完成: {done}"
+        )
+        item = iterator.Next()
+
+    print("\n=========== 迭代器模式结束 ===========")