说明：  编写基于命令行形式的个人信息管理（PIMCmd）程序，要求如下： This assignment involves the creation of simple Personal Information Management (个人信息管理 ) system that can deal with 4 kinds of items: todo items, notes, appointments and contacts. Each of these kinds of items is described in more detail below. The assignment requires that you create a class for each item type, and that each class extends an abstract base class provided for you. 文件列表： PIMAppointment.java PIMContact.java PIMEntity.java PIMManager.java PIMNote.java PIMToDo.java
(Each of these kinds of items is described in more detail below. The assignment requires that you create a class for each item type, and that each class extends an abstract base class provided for you.)