LinkedList 직접 구현

Contact.java

package com.test;

public class Contact {
    String name;
    String tel; // 010-1111-2222
    String gender;
    String birthDate; // 1991/09/01

    public Contact() {

    }

    public Contact(String name, String tel, String gender, String birthDate) {
        this.name = name;
        this.tel = tel;
        this.gender = gender;
        this.birthDate = birthDate;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getTel() {
        return tel;
    }

    public void setTel(String tel) {
        this.tel = tel;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getBirthDate() {
        return birthDate;
    }

    public void setBirthDate(String birthDate) {
        this.birthDate = birthDate;
    }

    @Override
    public String toString() {
        return "이름: " + this.name + " 전화번호: " + this.tel + " 성별 : " + this.gender + " 생년월일 : " + this.birthDate;
    }

    public String print() {
        return this.name + " | " + this.tel + " | " + this.gender + " | " + this.birthDate;
    }
}

LinkedList.java

package com.test.list;

import java.util.Iterator;
import java.util.NoSuchElementException;

public class LinkedList<Data> implements Iterable<Data> {
    private Node<Data> head;
    private Node<Data> tail;
    private int size;

    @Override
    public Iterator<Data> iterator() {
        return new ListIterator(head);
    }

    public static class Node<Data> {
        private Data data;
        private Node<Data> next;

        public Node(Data data) {
            this.data = data;
            this.next = null;
        }

        public Data getData() {
            return data;
        }
    }

    public void add(Data data) {
        Node<Data> newNode = new Node<Data>(data);
        if (size == 0) {
            head = newNode;
            size++;
            tail = head;
        } else {
            tail.next = newNode;
            tail = newNode; // 마지막 노드를 갱신
            size++;
        }
    }

    // index에 해당하는 Node 리턴
    public Node<Data> getNode(int index) {
        Node<Data> node = head;
        for (int i = 0; i < index; i++) {
            node = node.next;
        }
        return node;
    }

    public int size() {
        return size;
    }

    public String toString() {
        if(head == null) {
            return "[]";
        }
        Node<Data> temp = head;
        String str = "";
        while(temp.next != null) {
            str += temp.getData().toString();
//            str += temp.data.getName() + " | " + temp.data.getTel() + " | " +  temp.data.getGender() + " | " + temp.data.getBirthDate()+ "\n";
            temp = temp.next;
        }
        str += temp.getData().toString();
//        str += temp.data.getName() + " | " + temp.data.getTel() + " | " +  temp.data.getGender() + " | " + temp.data.getBirthDate();
        return str;
    }

    public void Remove(Node<Data> node) {
        // if first node,
        if (head == node) {
            head = node.next;
        } else {
            // find the prev node
            Node<Data> prev = this.head;
            while (prev.next != node && prev != tail) {
                prev = prev.next;
            }
            // found successfully, remove the node
            if (prev != tail) {
                prev.next = node.next;
            }
        }
        size--;
    }

    class ListIterator implements Iterator<Data> {
        Node<Data> cursor;

        ListIterator(Node<Data> startingPoint) {
            this.cursor = startingPoint;
        }

        @Override
        public boolean hasNext() {
            return cursor != null;
        }

        public Data next() {
            if (cursor == null)
                throw new NoSuchElementException();

            Data data = cursor.getData(); // 현재 데이터 가져옴
            cursor = cursor.next;
            return data;
        }
    }
}

LinkedListTest.java

package com.test.list;

import com.test.Contact;
import org.junit.jupiter.api.Assertions;

import java.util.Iterator;
import java.util.NoSuchElementException;

import static org.junit.jupiter.api.Assertions.*;

class LinkedListTest {
    LinkedList<Contact> makeDummyList() {
        LinkedList<Contact> list = new LinkedList<>();
        list.add(new Contact("담히", "010-1111-2222", "여", "1991/09/01"));
        list.add(new Contact("라이언", "010-1234-5678", "남", "1995/07/22"));
        list.add(new Contact("짠우", "010-8888-4444", "남", "1994/01/05"));
        return list;
    }

    @org.junit.jupiter.api.Test
    // 리스트에 0개 있을때 hasNext (false), next (no such element exception) 동작이 예상한대로 동작하는지
    void iteratorEmptyTest() {
        LinkedList<Contact> list = new LinkedList<>();
        Iterator<Contact> iter = list.iterator();

        assertFalse(iter.hasNext());
        assertThrows(NoSuchElementException.class, iter::next);
    }

    @org.junit.jupiter.api.Test
    // 리스트에 엘레먼트가 1개 있을때, has next가 한번 true가 되는지 확인, next가 한번 동작하고 exception을 내는지 확인
    void iteratorOneItemTest() {
        LinkedList<Contact> list = new LinkedList<>();
        list.add(new Contact("담히", "010-1111-2222", "여", "1991/09/01"));

        int hasNextCnt = 0;
        Iterator<Contact> iter = list.iterator();
        while (iter.hasNext()) {
            hasNextCnt++;
            iter.next();
        }
        assertEquals(1, hasNextCnt);

        // when everything is over
        assertFalse(iter.hasNext());
        assertThrows(NoSuchElementException.class, iter::next);
    }

    /**
     * 리스트에 엘레먼트가 n개 있을때 has next가 n번 되는지 확인, next가 n번 '순서대로' 잘 반환하고 exception을 반환하는지 확인
     */
    @org.junit.jupiter.api.Test
    void iteratorMultipleItemsTest() {
        LinkedList<Contact> list = makeDummyList();

        int hasNextCnt = 0;
        Iterator<Contact> iter = list.iterator();
        while (iter.hasNext()) {
            Contact data = list.getNode(hasNextCnt).getData();
            Assertions.assertSame(data, iter.next());
            hasNextCnt++;
        }
        assertEquals(list.size(), hasNextCnt);

        // when the iteration is over
        assertFalse(iter.hasNext());
        assertThrows(NoSuchElementException.class, iter::next);
    }

    @org.junit.jupiter.api.Test
    void addTest() {
        LinkedList<Contact> list = makeDummyList();
        LinkedList.Node<Contact> node = list.getNode(0);
        assertEquals("010-1111-2222", node.getData().getTel());

        node = list.getNode(1);
        assertEquals("010-1234-5678", node.getData().getTel());

        node = list.getNode(2);
        assertEquals("010-8888-4444", node.getData().getTel());
    }

    @org.junit.jupiter.api.Test
    void removeTest() {
        // #1
        LinkedList<Contact> list = makeDummyList();
        list.Remove(list.getNode(0));
        assertEquals("010-1234-5678", list.getNode(0).getData().getTel());

        // else
        list = makeDummyList();
        list.Remove(list.getNode(1));
        assertEquals("010-1111-2222", list.getNode(0).getData().getTel());
        assertEquals("010-8888-4444", list.getNode(1).getData().getTel());
    }
}

Main.java

package com.test;

import com.test.list.LinkedList;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        LinkedList<Contact> contactList = new LinkedList<>();

        boolean isRun = true;
        while (isRun) {
            System.out.println("주소 관리 검색 프로그램");
            System.out.println("1. 등    록");
            System.out.println("2. 출    력");
            System.out.println("3. 삭    제");
            System.out.println("4. 종    료");
            System.out.println("명령어를 선택하세요.");

            Scanner sc = new Scanner(System.in);
            int num = sc.nextInt();

            switch(num) {
                case 1 :
                    Contact contact = addContact(sc);
                    contactList.add(contact);
                    break;
                case 2 :
                    System.out.println("이름 | 전화번호 | 성별 | 생년월일");
                    /* Iterator<Contact> iter = contactList.iterator();

                    while (iter.hasNext()) {
                        Contact item = iter.next();
                        System.out.println(item.toString());
                    }*/

                    /*for (Contact cont : contactList) {
                        System.out.println(cont.toString());
                    }*/

                    contactList.forEach(e -> System.out.println(e.toString()));
                    break;
                case 3 :
                    System.out.println("삭제할 전화번호를 입력하세요.");
                    String tel = sc.next();

                    LinkedList.Node<Contact> node = null;
                    for(int i = 0; i < contactList.size(); i++) {
                        node = contactList.getNode(i);
                        if(node.getData().getTel().equals(tel)) {
                            break;
                        }
                    }
                    contactList.Remove(node);
                    // contactList.Remove(tel);
                    // 1. find a node that has specified telephone number.
                    // 2. delete that node
                    break;
                case 4 :
                    System.out.println("종료합니다.");
                    sc.close();
                    isRun = false;
                    break;
                default :
                    System.out.println("잘못된 입력입니다.");
                    break;
            }
        }
    }

    public static Contact addContact(Scanner sc) {
        Contact contact = new Contact();
        System.out.println("이름을 입력하세요.");
        String name = sc.next();
        System.out.println("전화번호를 입력하세요.");
        String tel = sc.next();
        System.out.println("성별을 입력하세요.");
        String gender = sc.next();
        System.out.println("생년월일을 입력하세요.");
        String birthDate = sc.next();
        contact.setName(name);
        contact.setTel(tel);
        contact.setGender(gender);
        contact.setBirthDate(birthDate);
        return contact;
    }
}