Java library management system

Next, create a group of operation classes. Each class corresponds to a user's actions AddOperation, DeleteOperation, FindOperation, DisplayOperation, BorrowOperation, ReturnOperation and UpdateOperation

Create the empty class first, and don't worry about the implementation details Abstract the benefits of Operation: low coupling between operations and between operations and users

3. Create user related classes

Create package user first

Create User class, which is an abstract class; Create a common User class, which is a subclass of User; Create administrator User class

4. Integration

Create the Main method and build the overall logic

5. Implement each specific Operation

3, Frame modeling

4, Basic framework code

book class:

package book_management;

//Book entity class
public class Book {
    //title
    private String bookName;
    //author
    private String author;
    //Price
    private double price;
    //Book category
    private String type;
    //Borrowing status: false by default
    private boolean isBorrowed;

    public Book(String bookName,String author,double price,String type){
        this.bookName = bookName;
        this.author = author;
        this.price = price;
        this.type = type;
    }

    //Only the attributes that need to be modified need to provide setter - price, type and borrowing status

    public void setPrice(double price){
        this.price = price;
    }
    public void setType(String type){
        this.type = type;
    }
    public void setBorrowed(boolean borrowed){
        isBorrowed = borrowed;
    }


    public String getBookName(){
        return bookName;
    }
    public String getAuthor(){
        return author;
    }
    public double getPrice(){
        return price;
    }
    public String getType(){
        return type;
    }
    public boolean isBorrowed(){
        return isBorrowed;
    }

    @Override
    public String toString() {
        return "Book{" +
                "bookName='" + bookName + '\'' +
                ", author='" + author + '\'' +
                ", price=" + price +
                ", type='" + type + '\'' +
                ", isBorrowed=" + isBorrowed +
                '}';
    }
}

bookList class:

package book_management;

import come.B;

import java.util.ArrayList;
import java.util.List;

//Bookshelves
public class BookList {
    // Books stores all the books in the current bookshelf, and each Book object is an entity of a Book
    private static List<Book> books = new ArrayList<>();
    // booksName stores all book names - query books, etc. are operated through book names
    private static List<String> bookName = new ArrayList<>();

    // Initialize books and booksName, and put the four famous works into the bookshelf by default
    // Initializing static variables using static code blocks
    static {
        books.add(new Book("Journey to the West","Wu Chengen",99.99,"novel"));
        books.add(new Book("The Dream of Red Mansion","Cao Xueqin",108.9,"novel"));
        books.add(new Book("Water Margin","Shi Naian",199.89,"novel"));
        books.add(new Book("Romance of the Three Kingdoms","Luo Guanzhong",145.39,"novel"));

        bookName.add("Journey to the West");
        bookName.add("The Dream of Red Mansion");
        bookName.add("Water Margin");
        bookName.add("Romance of the Three Kingdoms");
    }

    public void displayBooks(){
        for (Book book : books){
            System.out.println(book);
        }
    }

    public boolean contains(String booksName){
        return BookList.bookName.contains(booksName);
    }

    public void add(Book book){
        books.add(book);
        bookName.add(book.getBookName());
    }
}

Main method:

package book_management;

import java.util.Scanner;

//The entrance of the whole program
public class Main {
    private static Scanner scanner = new Scanner(System.in);
    public static void main (String[] args){
        User user = login();
        BookList bookList = new BookList();
        while(true){
            int choice = user.menu();
            if(choice == -1){
                System.out.println("ByeBye!");
                break;
            }
            user.doOperation(choice,bookList);
        }
    }

    private static User login() {
        System.out.println("Please enter user name:");
        String name = scanner.next();
        System.out.println("Please select your role. 1 is an ordinary user and 0 is an administrator");
        int choice = scanner.nextInt();
        if (choice == 1){
            return new NormalUser(name);
        }
        return new AdminUser(name);
    }
}

User class:

package book_management;

//User class - abstract class
//I don't know whether it's an ordinary user or an administrator
public abstract class User {
    //user name
    protected String name;
    //Method of authorized operation
    protected IOperation[] operations;
    // Menu. Only specific subclasses know what the menu looks like~~
    public abstract int menu();

    public void doOperation(int choice,BookList bookList){
        operations[choice - 1].work(bookList);
    }
}

Relevant operation class framework code:

package book_management;

import java.util.Scanner;

//Interface for operating bookshelf
// Add, delete, modify and check - borrow books - return books
// There are only global constants and abstract methods in the interface
public interface IOperation {
    // Global constant, shared by subclasses of all interfaces
    // static + final co modification
    Scanner scanner = new Scanner(System.in);
    //Operate in the corresponding bookshelf class
    void work(BookList bookList);
}

//Add books
public class AddOperation implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("Adding books is now in progress...");
    }
}

//Borrow books
public class BorrowOperation implements IOperation{
    @Override
    public void work(BookList bookList) {

    }
}

//Delete books
public class DeleteOperation implements IOperation{
    @Override
    public void work(BookList bookList) {

    }
}

//Show all books
public class DisplayAllBooks implements IOperation{
    @Override
    public void work(BookList bookList) {
        System.out.println("What you are doing now is to view all books!");
        bookList.displayBooks();
    }
}

//Find books
public class FindOperation implements IOperation{
    @Override
    public void work(BookList bookList) {

    }
}

//Return books
public class ReturnOperation implements IOperation{
    @Override
    public void work(BookList bookList) {

    }
}

//Update books
public class UpdateOperation implements IOperation{
    @Override
    public void work(BookList bookList) {

    }
}

Programmer Think

Java library management system

1, Core requirements

1. Simple login

2. Management end

Organize books (this function is extensible)

Consult books

Add books

Delete books

Print book list

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3. Client

Query books

Borrow books

Return books

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2, Class design

1. Create book related classes

Create a package book first

2. Create operation related classes

Create package operation first