refactor

school/Administrator.java

@@ -0,0 +1,23 @@
+package school;
+
+public class Administrator extends Person {
+    private String adminID;
+
+    public Administrator(String name, int age, String adminID) {
+        super(name, age);
+        this.adminID = adminID;
+    }
+
+    public void speak() {
+        System.out.println("I am an administrator, my name is " + getName() + ", and I am " + getAge()
+                + " years old. My admin ID is " + adminID + ".");
+    }
+
+    public String getAdminID() {
+        return adminID;
+    }
+
+    public void setAdminID(String adminID) {
+        this.adminID = adminID;
+    }
+}

school/ManagementSys.java

@@ -0,0 +1,40 @@
+package school;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ManagementSys {
+    private static ManagementSys instance = null;
+    private List<Person> persons;
+
+    private ManagementSys() {
+        persons = new ArrayList<Person>();
+    }
+
+    public static ManagementSys getInstance() {
+        if (instance == null) {
+            instance = new ManagementSys();
+        }
+        return instance;
+    }
+
+    public void addPerson(Person person) {
+        persons.add(person);
+    }
+
+    public void removePerson(Person person) {
+        persons.remove(person);
+    }
+
+    public void updatePerson(int index, Person person) {
+        persons.set(index, person);
+    }
+
+    public List<Person> getPersons() {
+        return persons;
+    }
+
+    public void setPersons(List<Person> persons) {
+        this.persons = persons;
+    }
+}

school/Manager.java

@@ -0,0 +1,24 @@
+package school;
+
+public class Manager extends Person {
+    private static Manager instance = null;
+
+    private Manager(String name, int age) {
+        super(name, age);
+    }
+
+    public static Manager getInstance(String name, int age) {
+        if (instance == null) {
+            instance = new Manager(name, age);
+        }
+        return instance;
+    }
+
+    public void manage() {
+        System.out.println("I am the administrator and I am responsible for managing everyone.");
+    }
+
+    public void speak() {
+        System.out.println("I am the manager, my name is " + getName() + ", and I am " + getAge() + " years old.");
+    }
+}

school/Person.java

@@ -0,0 +1,31 @@
+package school;
+
+public class Person {
+    private String name;
+    private int age;
+
+    public Person(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public void speak() {
+        System.out.println("I am a person, my name is " + name + ", and I am " + age + " years old.");
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+}

school/Staff.java

@@ -0,0 +1,23 @@
+package school;
+
+public class Staff extends Person {
+    private String staffID;
+
+    public Staff(String name, int age, String staffID) {
+        super(name, age);
+        this.staffID = staffID;
+    }
+
+    public void speak() {
+        System.out.println("I am a staff, my name is " + getName() + ", and I am " + getAge()
+                + " years old. My staff ID is " + staffID + ".");
+    }
+
+    public String getStaffID() {
+        return staffID;
+    }
+
+    public void setStaffID(String staffID) {
+        this.staffID = staffID;
+    }
+}

school/Student.java

@@ -0,0 +1,23 @@
+package school;
+
+public class Student extends Person {
+    private String studentID;
+
+    public Student(String name, int age, String studentID) {
+        super(name, age);
+        this.studentID = studentID;
+    }
+
+    public void speak() {
+        System.out.println("I am a student, my name is " + getName() + ", and I am " + getAge()
+                + " years old. My student ID is " + studentID + ".");
+    }
+
+    public String getStudentID() {
+        return studentID;
+    }
+
+    public void setStudentID(String studentID) {
+        this.studentID = studentID;
+    }
+}

school/Teacher.java

@@ -0,0 +1,23 @@
+package school;
+
+public class Teacher extends Person {
+    private String teacherID;
+
+    public Teacher(String name, int age, String teacherID) {
+        super(name, age);
+        this.teacherID = teacherID;
+    }
+
+    public void speak() {
+        System.out.println("I am a teacher, my name is " + getName() + ", and I am " + getAge()
+                + " years old. My teacher ID is " + teacherID + ".");
+    }
+
+    public String getTeacherID() {
+        return teacherID;
+    }
+
+    public void setTeacherID(String teacherID) {
+        this.teacherID = teacherID;
+    }
+}

school/Test.java

@@ -0,0 +1,40 @@
+package school;
+
+import library.Administrator;
+
+public class Test {
+    public static void main(String[] args) {
+        ManagementSys sys = ManagementSys.getInstance();
+
+        Student std = new Student("John", 20, "S2201110101");
+        sys.addPerson(std);
+
+        Teacher tch = new Teacher("Tom", 30, "T2201110101");
+        sys.addPerson(tch);
+
+        Staff stf = new Staff("Jerry", 40, "S2201110101");
+        sys.addPerson(stf);
+
+        Administrator adm = new Administrator("Jack", 50, "A2201110101");
+        sys.addPerson(adm);
+
+        Manager mgr = Manager.getInstance("Marry", 60);
+        sys.addPerson(mgr);
+
+        for (Person person : sys.getPersons()) {
+            person.speak();
+        }
+
+        sys.removePerson(std);
+        System.out.println("After removing John");
+        for (Person person : sys.getPersons()) {
+            person.speak();
+        }
+
+        sys.updatePerson(0, new Teacher("Tom", 30, "T2201110102"));
+        System.out.println("After updating Tom");
+        for (Person person : sys.getPersons()) {
+            person.speak();
+        }
+    }
+}