jkost.github.io/Courses/Mathesis/Intro2ProgrammingWithJava/Week4/4.1-Inheritance/sandbox/ex2.html at master · jkost/jkost.github.io · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
<!DOCTYPE html>
<html lang="en">
<head>
  <link rel="stylesheet" href="https://javaalmanac.io/almanac.min.css">
</head>
<body>

<div class="content" id="content">

<sandbox version="java17" mainclass="School" preview="true" v-cloak>
<sandbox-source name="School.java">import java.util.Arrays;

class Person {
 // γράψτε τον κώδικά σας εδώ και κάντε τις απαραίτητες αλλαγές στις υπόλοιπες κλάσεις
}

class Teacher {
}

class Student {
    private static final int MAX_SIZE = 20;
    private static final String NONE = "<Κενό>";

    private static int amCounter = 0;

    private final int am;
    private String firstName = NONE;
    private String lastName = NONE;
    private int age = -1;  // 15-18
    private ClassRoom classRoom;

    public Student(String firstName, String lastName, int age) {
        am = ++amCounter;
        if (isNameValid(firstName)) {
            this.firstName = firstName.trim();
        }
        if (isNameValid(lastName)) {
            this.lastName = lastName.trim();
        }
        if (isAgeValid(age)) {
            this.age = age;
        }
    }

    public int getAm() {
        return am;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = isNameValid(firstName) ? firstName.trim() : NONE;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = isNameValid(lastName) ? lastName.trim() : NONE;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = isAgeValid(age) ? age : -1;
    }

    public ClassRoom getClassRoom() {
        return classRoom;
    }

    void setClassRoom(ClassRoom classRoom) {
        this.classRoom = classRoom;
    }

    @Override
    public String toString() {
        return "Student{" + "am=" + am + ", firstName=" + firstName + ", lastName=" + lastName + ", age=" + age + ", classRoom=" + classRoom + '}';
    }

    private boolean isAgeValid(int inAge) {
        return inAge >= 15 && inAge <= 18;
    }

    private boolean isNameValid(String name) {
        return name != null && !name.isBlank() && name.length() <= MAX_SIZE;
    }
}

class ClassRoom {

    private static final int DEFAULT_SIZE = 30;
    private static final String NO_CLASSROOM = "--";
    private static final int CLASSROOM_NAME_LENGTH = 2;

    private final String name;
    private final int size;
    private Student[] students;
    private int index = 0;

    public ClassRoom(String name, int size) {
        this.name = isClassRoomNameValid(name) ? name : NO_CLASSROOM;
        this.size = isSizeValid(size) ? size : DEFAULT_SIZE;
        this.students = new Student[size];
    }

    public ClassRoom(String name) {
        this(name, DEFAULT_SIZE);
    }

    public String getName() {
        return name;
    }

    public int getSize() {
        return size;
    }

    public void addStudent(Student student) {
        if (student != null && index < size) {
            students[index++] = student;
            student.setClassRoom(this);
        }
    }

    public void removeStudent(int am) {
        int indx = contains(students, am);
        if (indx != -1) {
            Student student = students[indx];
            if (remove(indx)) {
                student.setClassRoom(null);
            }
        }
    }

    public void removeStudent(Student student) {
        if (student != null) {
            removeStudent(student.getAm());
        }
    }

    public void removeAllStudents() {
        for (Student student : students) {
            student.setClassRoom(null);
        }
        Arrays.fill(students, null);
        index = 0;
    }

    private int contains(Student[] students, int am) {
        for (int i = 0; i < students.length; i++) {
            Student student = students[i];
            if (student.getAm() == am) {
                return i;
            }
        }
        return -1;
    }

    private boolean remove(int indx) {
        if (indx < 0 || indx >= this.students.length) return false;
        Student[] newStudents = new Student[this.students.length - 1];
        // αντιγραφή από το 0 μέχρι το students[index-1]
        System.arraycopy(this.students, 0, newStudents, 0, indx);
        // αντιγραφή από students[index+1] μέχρι students[students.length-1]
        System.arraycopy(this.students, indx + 1, newStudents, indx, this.students.length - indx - 1);
        this.students = newStudents;
        index--;
        return true;
    }

    @Override
    public String toString() {
        return "ClassRoom{" + "name=" + name + ", size=" + size + ", numOfStudents=" + index + '}';
    }

    private boolean isSizeValid(int inSize) {
        return inSize >= 10 && inSize <= DEFAULT_SIZE;
    }

    private boolean isClassRoomNameValid(String classRoom) {
        return classRoom != null && !classRoom.isBlank()
                && classRoom.length() == CLASSROOM_NAME_LENGTH
                && (classRoom.startsWith("Α")
                || classRoom.startsWith("Β")
                || classRoom.startsWith("Γ"))
                && classRoom.charAt(1) >= '1'
                && classRoom.charAt(1) <= '9';
    }
}

public class School {
    private static final ClassRoom[] classRooms = {
        new ClassRoom("Α1"),
        new ClassRoom("Α2", 28),
        new ClassRoom("Α3", 25),
        new ClassRoom("Β1"),
        new ClassRoom("Β2", 28),
        new ClassRoom("Β3", 25),
        new ClassRoom("Γ1"),
        new ClassRoom("Γ2", 26),
        new ClassRoom("Γ3", 22),

    };

    public static void main(String[] args) {
        System.out.println("=== Create student ioannis ====");
        Student ioannis = new Student("Γιάννης", "Αντεκοτούμπο", 16);
        System.out.println("AM: " + ioannis.getAm());
        System.out.println("ClassRoom: " + ioannis.getClassRoom());

        System.out.println("\n=== Add student ioannis to classroom 'B1' ====");
        classRooms[3].addStudent(ioannis);
        System.out.println(ioannis.getClassRoom());
        System.out.println(ioannis);

        System.out.println("\n=== Create student aliki and add to classroom 'B1' ====");
        Student aliki = new Student("Αλίκη", "Βουγιουκλάκη", 17);
        classRooms[3].addStudent(aliki);
        System.out.println(aliki);
        System.out.println(classRooms[3]);

        System.out.println("\n=== Remove student ioannis from classroom 'B1' ====");
        classRooms[3].removeStudent(ioannis.getAm());
        System.out.println(ioannis);
        System.out.println(classRooms[3]);

        System.out.println("\n=== Create a teacher ====");
        Teacher socrates = new Teacher("AB123456", "Σωκράτης", "Σωκράτης");
        socrates.addLesson("Φιλοσοφία");
        socrates.addLesson("Αρχαία Ελληνικά");
        System.out.println(socrates);
    }

}
</sandbox-source>
</sandbox>
</div>
<script src="https://javaalmanac.io/app/sandbox-bundle.js"></script>
<script>new Vue({ el: '#content' })</script>
</body>
</html>