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/*

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  */
  package work;

import java.io.FileInputStream;
import java.security.MessageDigest;
import java.util.Scanner;
import javax.swing.JOptionPane;

public class JavaApplication1 {
public static void main(String[] args) throws Exception {

    Scanner scnr = new Scanner(System.in);
    FileInputStream admin = null; //file input streams
    FileInputStream zookeeper = null;
    FileInputStream veterinarian = null;


    //create array based on credentials.txt
    final int NUM_ELEMENTS = 6;
    String[] storedUsername = new String[NUM_ELEMENTS];
    String[] role = new String[NUM_ELEMENTS];
    String[] hashPassword = new String[NUM_ELEMENTS];
    String username = "";
    String password = "";
    String hash = "";
    String userRole = "";
    userRoles userInput = new userRoles();
    int i = 0; //loop variable
    int j = 0; //loop variable
    int user = 0;
    boolean verified = false;

    //populate username/password array
    storedUsername[i] = "griffin.keyes";          hashPassword[i] = "108de81c31bf9c622f76876b74e9285f"; ++i;
    storedUsername[i] = "rosario.dawson";       hashPassword[i] = "3e34baa4ee2ff767af8c120a496742b5"; ++i;
    storedUsername[i] = "bernie.gorilla";          hashPassword[i] = "a584efafa8f9ea7fe5cf18442f32b07b"; ++i;
    storedUsername[i] = "donald.monkey";          hashPassword[i] = "17b1b7d8a706696ed220bc414f729ad3"; ++i;
    storedUsername[i] = "jerome.grizzlybear";      hashPassword[i] = "3adea92111e6307f8f2aae4721e77900"; ++i;
    storedUsername[i] = "bruce.grizzlybear";     hashPassword[i] = "0d107d09f5bbe40cade3de5c71e9e9b7"; ++i;

    //display usage information for user
    JOptionPane.showMessageDialog(null, "All entries are case sensitive.\n" + 
            "Enter \"quit\" at any time to exit.", "Authentication System", JOptionPane.PLAIN_MESSAGE);

        //prompt user for credentials
        username = (String)JOptionPane.showInputDialog(null, "Enter username: ", "Authentication System", JOptionPane.PLAIN_MESSAGE); 
            if (username.equals("quit")){
                JOptionPane.showMessageDialog(null, "You have chosen to exit. Goodbye.", "Authentication System", JOptionPane.WARNING_MESSAGE);
                return;
            }
        password = (String)JOptionPane.showInputDialog(null, "Enter password: ", "Authentication System", JOptionPane.PLAIN_MESSAGE);
            if (password.equals("quit")){
                JOptionPane.showMessageDialog(null, "You have chosen to exit. Goodbye.", "Authentication System", JOptionPane.WARNING_MESSAGE);
                return;
            }

        //check the validation of the user no more then 3 times.
        for (i = 0; i < 3; ++i){

            //compare user credentials to storedUsername and convert password
            for (j = 0; j < NUM_ELEMENTS; ++j) {        
                if (username.equals(storedUsername[j])){
                    String original = password;  //provided MD5Digest code
                    MessageDigest md = MessageDigest.getInstance("MD5");
                    md.update(original.getBytes());
                    byte[] digest = md.digest();
                    StringBuffer sb = new StringBuffer();
                    for (byte b : digest) {
                        sb.append(String.format("%02x", b & 0xff));
                    }

                    verified = true;
                    user = j;
                    hash = sb.toString();
                }
            }
                    //if there are invalid credentials prompt for re-entry
                    if (!hash.equals(hashPassword[user])) {
                        verified = false;
                        if (i<2) {
                            JOptionPane.showMessageDialog(null, "Invalid user credentials. " + (2-i) 
                                    + " attempt(s) remaining.", "Authentication System", JOptionPane.PLAIN_MESSAGE);
                            username = (String)JOptionPane.showInputDialog(null, "Enter username: ", "Authentication System",
                                    JOptionPane.PLAIN_MESSAGE); 
                                if (username.equals("quit")){
                                    JOptionPane.showMessageDialog(null, "You have chosen to exit. Goodbye.", "Authentication System",
                                            JOptionPane.WARNING_MESSAGE);
                                    break;
                                }
                            password = (String)JOptionPane.showInputDialog(null, "Enter password: ", "Authentication System",
                                    JOptionPane.PLAIN_MESSAGE);
                                if (password.equals("quit")){
                                    JOptionPane.showMessageDialog(null, "You have chosen to exit. Goodbye.", "Authentication System",
                                            JOptionPane.WARNING_MESSAGE);
                                    break;
                                }
                        }
                        //give error message if incorrect password on final attempt
                        if((!verified) && (i==2)) {
                            JOptionPane.showMessageDialog(null, "Could not verify credentials. Goodbye.", "Authentication System",
                                    JOptionPane.ERROR_MESSAGE);
                            break;
                        }
                    }

                    //user credentials verified
                    else {
                        userInput.setUser(username); //set username
                        userRole = userInput.getRole(); //find corresponding role for user
                        userInput.printWelcome(); //display welcome message to user

                        return;

                    }
        }
 }

}

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