final project q12 giveup

finalproject/Question12/CLI.java

@@ -0,0 +1,145 @@
+/*
+ * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
+ * Date: 2022-04-25
+ * Description: This is the CLI class.
+ */
+
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+public class CLI {
+	private static Scanner input = new Scanner(System.in);
+
+	/**
+	 * Read one line from CLI.
+	 *
+	 * @param message Hint printed to screen
+	 * @return one line input
+	 */
+	private static String readLine(String message) {
+		System.out.print(message);
+		return input.nextLine();
+	}
+
+	/**
+	 * Read one positive integer.
+	 *
+	 * @param message HINT printed to screen
+	 * @return one positive integer
+	 */
+	private static int readPosInt(String message) {
+		while (true) {
+			System.out.print(message);
+			try {
+				int result = input.nextInt();
+				input.nextLine();
+				if (result >= 0) {
+					return result;
+				} else {
+					System.out.println("Positive integers only!");
+				}
+			} catch (InputMismatchException e) {
+				System.out.println("You must type an integer!");
+				input.nextLine();
+			}
+		}
+	}
+
+	public static void main(String[] args) {
+		int book;
+		String username;
+		String menuHint = "Type an action (total:1 add:2 get:3 more:4 less:5 quit:6): ";
+		String userRoleHint = "Type the user role (lender:1 borrower:2): ";
+
+		Library library = new Library("UIC Library");
+		while (true) {
+			switch (readPosInt(menuHint)) {
+				// total
+				case 1:
+					System.out.println("Total number of borrowed books: "
+							+ library.totalBorrowedBooks());
+					break;
+				// add
+				case 2:
+					switch (readPosInt(userRoleHint)) {
+						// lender
+						case 1:
+							username = readLine("Enter the name of the user: ");
+							book = readPosInt(
+									"Enter the initial number of borrowed books: ");
+							Lender lender = new Lender(username, book);
+							library.addUser(lender);
+							System.out.println("Lender \"" + username + "\" lending " + book
+									+ " book(s) has been added.");
+							break;
+						// borrower
+						case 2:
+							username = readLine(
+									"Enter the name of the user: ");
+							book = readPosInt(
+									"Enter the initial number of borrowed books: ");
+							try {
+								library.addUser(new Borrower(username, book));
+								System.out.println("Borrower \""
+										+ username
+										+ "\" borrowing "
+										+ book
+										+ " book(s) has been added.");
+							} catch (NotALenderException e) {
+								System.out.println("BUG! This must never happen!");
+								System.exit(1);
+							}
+							break;
+						default:
+							System.out.println("Unknown user role!");
+							break;
+					}
+					break;
+				// get
+				case 3:
+					username = readLine("Enter the name of the user: ");
+					try {
+						System.out.println(username + " borrows "
+								+ library.getBook(username) + " book(s).");
+					} catch (UnknownUserException e) {
+						System.out.println("User " + username + " unknown.");
+					}
+					break;
+				case 4:
+					username = readLine("Enter the name of the user: ");
+					book = readPosInt("Enter the number of books: ");
+					try {
+						library.moreBook(username, book);
+					} catch (NotALenderException e) {
+						System.out.println("BUG! This must never happen!");
+					} catch (UnknownUserException e) {
+						System.out.println("User " + username + " unknown.");
+					}
+					break;
+				case 5:
+					username = readLine("Enter the name of the user: ");
+					book = readPosInt("Enter the number of books: ");
+					try {
+						// decrease numbers
+						try {
+							library.moreBook(username, -book);
+						} catch (NotALenderException e) {
+							System.out.println("A borrower cannot lend "
+									+ (-(library.getBook(username) - book))
+									+ " book(s).");
+						}
+					} catch (UnknownUserException e) {
+						System.out.println("User " + username + " unknown.");
+					}
+					break;
+				case 6:
+					System.out.println("Goodbye!");
+					System.exit(0);
+					break;
+				default:
+					System.out.println("Unknown action!");
+					break;
+			}
+		}
+	}
+}