【Scala】图书项目系统代码演练3.1/BookService

package org.app
package serviceimport models.{BookModel, BorrowRecordModel}import org.app.dao.{BookDAO, BorrowRecordDAO}import java.time.LocalDateTime
import scala.collection.mutable.ListBuffer// 图书业务逻辑层
class BookService {private val bookDAO = new BookDAO()private val borrowRecordDAO = new BorrowRecordDAO()// 查询所有的图书//  def searchBooks(query:String): 图书列表List(Book对象)def searchBooks(query:String):ListBuffer[BookModel] = {// 从文本文件中读取书本信息，并保存列表中，返回val books = bookDAO.loadBooks()query match {case "" => books // 没有条件，就返回全部case _ => books.filter(b => b.name.contains(query) || b.author.contains(query)) // 有条件，就过滤}}// 普通用户，借阅图书def borrowBook(username:String, bookId:Int):Boolean = {// （1）根据图书的ID，查询图书，判断图书是否存在val books = bookDAO.loadBooks()// 所有的借阅记录val records = borrowRecordDAO.loadBorrowRecords()val book = books.find(b => b.id == bookId)if(book.nonEmpty){val b = book.get//   （2）判断图书是否已经被借出if(b.available){// （3）借阅图书 更新这本书的状态b.available = false// 把更新之后的图书的信息写回txt文件bookDAO.saveBooks(books)// 添加一条借阅记录records += BorrowRecordModel(username, b.id,b.name, LocalDateTime.now().toString)// 写借阅记录回文件borrowRecordDAO.saveBorrowRecords(records)println("借阅成功，已保存借阅记录！")true} else {println("这本书被借走了")false}} else {println("没有找到这本书")false}}//普通用户，查询自己的借阅记录def queryBorrowedBooks(username: String):ListBuffer[BorrowRecordModel] = {//  1.把所有的记录全读出来val records = borrowRecordDAO.loadBorrowRecords()//  2.过滤出当前用户的借阅记录records.filter(r => r.userName == username)}// 普通用户.归还自己借的某一本书def returnBook(username: String, bookId: Int): Boolean = {// 1.确定这本书是他本人借的并处于没有归还的状态queryBorrowedBooks(username).find(r => r.bookID == bookId && r.returnDate.isEmpty) match {case Some(record) =>// 2.更新书的状态// 2.1 加载全部的书val books = bookDAO.loadBooks()// 2.2 选择当前这本书val b = books.find(_.id == bookId).getb.available = true// 2.3 把更新之后的状态写回.txt文件bookDAO.saveBooks(books)// 3.更新借阅记录的状态//        3.1 加载全部的借阅记录val records = borrowRecordDAO.loadBorrowRecords()//        3.2 找到当前这本书的借阅记录 bookID,userName,returnDate = Noneval r = records.find(r => r.bookID == bookId && r.userName == username && r.returnDate.isEmpty).getr.returnDate = Some(LocalDateTime.now().toString)//        3.3 把更新之后的状态写回.txt文件borrowRecordDAO.saveBorrowRecords(records)truecase None => false}}// 添加图书def addBook(book: BookModel): Unit = {// 1. 生成一个book ID// 查询所有图书. 找到最大的ID,+1var id = 1val books = bookDAO.loadBooks()if (books.nonEmpty) {id = books.map(_.id).max + 1}// 2. 更新IDval newBook = book.copy(id = id)// 3. 把新的图书添加到booksbooks += newBook// 4.写回到.txt中bookDAO.saveBooks(books)}
}