도서관 시스템

[백종현]

package ch20.library;

import java.util.*;

public class LibrarySystem { //도서관 관리 시스템
private Library ACCESSS; //잭 데이터 저장소
Set<User> users = new HashSet<>();
long userId = 2000L;
LibrarySystem(){ACCESSS = Library.getACCESS();}
public void signIn (String userName){users.add(new User(userId++, userName));}//회원가입
public void addBook(String selfName,String bookName){ //책 추가
ACCESSS.addBook(selfName,bookName);
}
public void borrowBook(long userId, String selfName){ //책 대출
for (User u : users){
if (u.getId() == userId){
System.out.println(u.getName());
u.borrowBook(ACCESSS.borrowBook(selfName));
System.out.println("성공");
return;
}
}
System.out.println("err");
}
public void userBorrowBooks(long userId){ //이용자가 빌린 책
for (User u : users){
if (u.getId() == userId){
System.out.println(u.getName());
u.myBooks();
return;
}
}
System.out.println("err");
}

public void returnBook(long userId, String bookName, String selfName){//책 반납
for (User u : users){
if (u.getId() == userId){
System.out.println(u.getName());
ACCESSS.returnBook(selfName, u.returnBook(bookName));
return;
}
}
System.out.println("err");
}
public void showBoolSelf(String selfName){// 책장 책 목록
ACCESSS.showBoolSelf(selfName);
}
}
class Library{// 책 데이터 저장소
private static Library ACCESS;
private Map<String, BookSelf_> bookSelf = new HashMap<>(); //책장 A,B
private long bookId = 1000L;
private Library(){
bookSelf.put("A", new BookSelfA());
bookSelf.put("B", new BookSelfB());
}
public static synchronized Library getACCESS(){
if (ACCESS == null){
ACCESS = new Library();
}
return ACCESS;
}
public void addBook(String selfName, String bookName){//책 추가
bookSelf.get(selfName).addBook(new Book(bookId++, bookName));
}
public Book borrowBook(String selfName){// 대출
return bookSelf.get(selfName).borrowBook();
}
public void returnBook(String selfName,Book book){//반납
bookSelf.get(selfName).returnBook(book);
}

public void showBoolSelf(String selfName){//책장 책 목록
System.out.println(bookSelf.get(selfName));
}
}
class Book{
private long id;
private String name;
Book(long id, String name){this.id = id; this.name = name;}
public long getId() {return id;}
public String getName() {return name;}

@Override
public boolean equals(Object object) {
if (this == object) return true;
if (object == null || getClass() != object.getClass()) return false;
Book book = (Book) object;
return id == book.id;
}
@Override
public int hashCode() {return Objects.hash(id);}

@Override
public String toString() {
return "Book{" +
"name='" + name + '\'' +
'}';
}
}

class User{
private long id;
private String name;
private Set<Book> books = new HashSet<>();//빌린 책 목록
User(long id, String name){this.name = name; this.id = id;}
public long getId() {return id;}
public String getName() {return name;}
public void borrowBook(Book book){books.add(book);}//대출
public Book returnBook(String bookName){//반납
Book reBook;
for (Book book : books){
if (book.getName().equals(bookName)){
reBook = book;
books.remove(book);
return reBook;
}
}
System.out.println("not found");
return null;
}
public void myBooks(){//빌린 책 복록 조회
System.out.println(books);
}
@Override
public boolean equals(Object object) {
if (this == object) return true;
if (object == null || getClass() != object.getClass()) return false;
User user = (User) object;
return id == user.id;
}
@Override
public int hashCode() {return Objects.hash(id);}
}
interface BookSelf_{
void addBook(Book book);//책 추가
Book borrowBook();//대출
void returnBook(Book book);//반납

}
abstract class BookSelf implements BookSelf_{
protected List<Book> books = new ArrayList<>();

@Override
public void addBook(Book book) {books.add(book);}

protected boolean canBorrow() {
return !books.isEmpty();
}

@Override
public String toString() {
return books.toString();
}
}

class BookSelfA extends BookSelf{
@Override
public Book borrowBook() {
if (canBorrow())
return books.remove(0);
return null;
}
@Override
public void returnBook(Book book) {
addBook(book);
}
}

class BookSelfB extends BookSelf{
@Override
public Book borrowBook() {
if(canBorrow())
return books.remove(books.size() -1);
return null;
}
@Override
public void returnBook(Book book) {
addBook(book);
}
}

class Main_{
public static void main(String[] args) {
LibrarySystem li = new LibrarySystem();
li.addBook("A","노인과 바다");
li.addBook("A","어린왕자");
li.addBook("A", "개미");
li.showBoolSelf("A");
li.addBook("B", "삼국지");
li.addBook("B", "연금술사");
li.addBook("B", "해리포터");
li.showBoolSelf("B");

li.signIn("a");
li.signIn("b");

li.borrowBook(2000L,"A");
li.borrowBook(2001L, "A");
li.borrowBook(2000L,"B");

li.userBorrowBooks(2000L);
li.userBorrowBooks(2001L);

li.returnBook(2000L,"해리포터", "A");
li.returnBook(2001L,"어린왕자", "B");
li.returnBook(2000L, "노인과 바다", "B");
li.showBoolSelf("A");
li.showBoolSelf("B");
}
}