实现备忘录模式示例，添加原发器、备忘录及负责人类，增强代码可读性

2026-01-06 23:32:11 +08:00
parent 78d4634cf3
commit 5022b481a4
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+/*
+实例：
+汤宝宝聘请了一位私人助理，帮助他管理日常事务。
+他负责记录汤宝宝的状态，以便在需要时恢复到之前的状态。
+*/
+
+class Tom {
+  state: string;
+
+  constructor(state: string) {
+    this.state = state;
+  }
+
+  createMemento(): Memento {
+    console.log(`汤宝宝创建了备忘录，状态为: ${this.state}`);
+    return new Memento(this.state);
+  }
+
+  restoreMemento(memento: Memento): void {
+    this.state = memento.getState();
+    console.log(`汤宝宝恢复了状态: ${this.state}`);
+  }
+}
+
+class Memento {
+  private state: string;
+
+  constructor(state: string) {
+    this.state = state;
+  }
+
+  getState(): string {
+    return this.state;
+  }
+
+  setState(state: string): void {
+    this.state = state;
+  }
+}
+
+class Assistant {
+  private mementos: Memento[];
+  constructor() {
+    this.mementos = [];
+  }
+
+  backup(tom: Tom): void {
+    const memento = tom.createMemento();
+    this.mementos.push(memento);
+    console.log("私人助理备份了汤宝宝的状态");
+  }
+
+  undo(tom: Tom): void {
+    if (this.mementos.length === 0) {
+      console.log("没有备份可供恢复");
+      return;
+    }
+    const memento = this.mementos.pop()!;
+    console.log("私人助理恢复了汤宝宝的状态");
+    tom.restoreMemento(memento);
+  }
+}
+
+(function () {
+  console.log("============= 备忘录模式 =============");
+  const tom = new Tom("开心");
+  console.log(`汤宝宝的当前状态：${tom.state}`);
+  const assistant = new Assistant();
+
+  assistant.backup(tom);
+  tom.state = "生气";
+  console.log(`汤宝宝的当前状态：${tom.state}`);
+
+  assistant.undo(tom);
+
+  console.log("\n=========== 备忘录模式结束 ===========");
+})();