FlightService.java

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class FlightService {
  public static final String DBCONFIG_FILENAME = "dbconn.properties";

  public static void usage() {
    /* prints the choices for commands and parameters */
    System.out.println();
    System.out.println(" *** Please enter one of the following commands *** ");
    System.out.println("> create <username> <password> <Email-ID>");
    System.out.println("> login <username> <password>");
    System.out.println("> logout");
    System.out.println("> add");
    System.out.println("> view");
    System.out.println("> commit <message>");
    System.out.println("> versions <project id>");
    System.out.println("> delete <project id>");
    System.out.println("> push");
    System.out.println("> quit");
  }

  public static String[] tokenize(String command) {
    String regex = "\"([^\"]*)\"|(\\S+)";
    Matcher m = Pattern.compile(regex).matcher(command);
    List<String> tokens = new ArrayList<>();
    while (m.find()) {
      if (m.group(1) != null) tokens.add(m.group(1));
      else tokens.add(m.group(2));
    }
    return tokens.toArray(new String[0]);
  }

  public static String execute(Query q, String command) {
    String response;
    String[] tokens = tokenize(command.trim());
    if (tokens.length == 0) response = "Please enter a command";
    else if (tokens[0].equals("login")) {
      if (tokens.length == 3) {
        /* authenticate the user */
        String username = tokens[1];
        String password = tokens[2];
        response = q.loginUser(username, password);
      } else response = "Error: Please provide a username and password";
    } else if (tokens[0].equals("create")) {
      /* create a new customer */
      if (tokens.length == 4) {
        String username = tokens[1];
        String password = tokens[2];
        String email = tokens[3];
        response = q.createUser(username, password, email);
      } else response = "Error: Please provide a username, password, and email for the account";
    } else if (tokens[0].equals("logout")) {
      response = q.logOut();
    } else if (tokens[0].equals("add")) {
      response = q.add();
    } else if (tokens[0].equals("view")) {
      response = q.view();
    } else if (tokens[0].equals("delete")) {
      if (tokens.length == 2) {
        int project_id = Integer.parseInt(tokens[1]);
        response = q.delete(project_id);
      } else {
        response = "Error: Please provide a project_id";
      }
    } else if (tokens[0].equals("commit")) {
      if (tokens.length == 2) {
        String message = tokens[1];
        response = q.commit(message);
      } else {
        response = "Error: Please provide a commit message";
      }
    } else if (tokens[0].equals("push")) {
      response = q.push();
    } else if (tokens[0].equals("versions")) {
      if (tokens.length == 2) {
        String id = tokens[1];
        response = q.versions(Integer.parseInt(id));
      } else {
        response = "Error: Please provide a version number";
      }
    }
    // } else if (tokens[0].equals("reservations")) {
    //   /* list all reservations */
    //   response = q.transaction_reservations();
    // } else if (tokens[0].equals("pay")) {
    //   /* pay for an unpaid reservation */
    //   if (tokens.length == 2) {
    //     int reservation_id = Integer.parseInt(tokens[1]);
    //     // System.out.println("Paying reservation.");
    //     response = q.transaction_pay(reservation_id);
    //   } else response = "Error: Please provide a reservation_id";
    // } else if (tokens[0].equals("cancel")) {
    //   /* cancel a reservation */
    //   if (tokens.length == 2) {
    //     int reservation_id = Integer.parseInt(tokens[1]);
    //     // System.out.println("Canceling reservation.");
    //     response = q.transaction_cancel(reservation_id);
    //   } else response = "Error: Please provide a reservation_id";
    // }
    else if (tokens[0].equals("quit")) response = "Goodbye\n";
    else response = "Error: unrecognized command '" + tokens[0] + "'";

    return response;
  }

  /* REPL (Read-Execute-Print-Loop) */
  public static void menu(Query q) throws Exception {
    while (true) {
      usage();

      BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
      System.out.print("> ");

      String command = r.readLine();
      String response = execute(q, command);
      System.out.print(response);

      if (response.equals("Goodbye\n")) break;
    }
  }

  public static void main(String[] args) throws Exception {
    /* prepare the database connection stuff */
    Query q = new Query(DBCONFIG_FILENAME);
    q.openConnection();
    q.prepareStatements();
    menu(q); /* menu(...) does the real work */
    q.closeConnection();
  }
}