Java

Enterprise application architecture

16-Aug-15 21:02

Check the documentation for the device to see how it interfaces to your computer. Most manufacturers provide a library that handles the physical connection and allows applications to receive the data.

Neo1010114-Aug-15 11:15

Neo10101

14-Aug-15 11:15

I took a look at someone's code here and I am trying to understand its architecture:
We are looking at a classic enterprise architecture using Spring core for dependency injection.

Java

import org.springframework.beans.factory.annotation.Autowired;

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

public class FavoriteService {
    @Autowired
    private Users users;

    public boolean checkLogin(String username, String password) {
        return users.login(username, password);
    }


    public void addUser(String root, String rootpasswd, String username, String password) {
        if(root.equals("root")&&rootpasswd.equals("rootpasswd")) {
            users.addUser(username, password);
        }
    }

    public User getUser(String username){
        return users.getUser(username);
    }

    public List<String> getFavorites(String username, String password) {
        if (getUser(username) == null) return new ArrayList<>();
    }

    public void addFavorite(String username, String password, String favorite1) {
            users.addFavorite(username,password,favorite1);
    }

    public void removeFavorite(String username, String password, String favorite1) {
        users.removeFavorite(username,password,favorite1);
    }

    public void addFavorite(String username, String password, String favorite1) {

    }
}

Java

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

public class User {
    private final String username;
    private final String password;
    private final List favorites = new ArrayList<String>();

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public String getPassword() {
        return password;
    }

    public String getUsername() {
        return username;
    }

    public List<String> getFavorites(){
        return favorites;
    }

    public void addFavorite(String favorite){
        favorites.add(favorite);
    }

    public void removeFavorite(String favorite) {
        favorites.remove(favorite);
    }
}

Java

public interface UserDao {
    public void create(User user);

    public User getUser(String username);
}

Java

import java.util.HashMap;
import java.util.Map;

public class UserDaoWithMap implements UserDao {
    private Map<String, User> users;

    public UserDaoWithMap() {
        this.users = new HashMap<>();
    }

    @Override
    public void create(User user) {
        users.put(user.getUsername(), user);
    }

    @Override
    public User getUser(String username) {
        return users.get(username);
    }
}

Java

    public class Users {
    
    @Autowired
    private UserDao userDao;

    public void addUser(String username, String password) {
        User user = new User(username, password);
        userDao.create(user);
    }

    public User getUser(String username){
        return userDao.getUser(username);
    }

    public boolean login(String username, String password) {
        User user = userDao.getUser(username);
        if (user == null) return false;
        if (!user.getPassword().equals(password)) return false;
        return true;
    }

   public void addFavorite(String username, String password, String favorite1) {
        User user = userDao.getUser(username);
        if(login(username,password)){ 
            user.addFavorite(favorite1);
        }
    }

    public void removeFavorite(String username, String password, String favorite1) {
        User user = userDao.getUser(username);
        if(login(username,password)) {
            user.removeFavorite(favorite1);
        }
    }
}

I understand the following enterprise roles are in place:
service: FavoriteService
model: User
dao: UserDao, UserDaoWithMap

However, I don't understand what enterprise role the 'Users' class fulfills. I don't see where in the architecture it fits - it looks to me like some sort of helper class. Though, it does look like it has business value because it uses the UserDao.
Does anyone see any standard pattern here? Does the 'Users' class have an enterprise purpose or is it just some custom helper class?

I think it is a Manager/Controller type of class.

modified 14-Aug-15 17:32pm.

Re: Enterprise application architecture

Richard MacCutchan14-Aug-15 20:51

Re: Enterprise application architecture

14-Aug-15 20:51

Neo10101 wrote:
I took a look at someone's code here

Then you should direct your question to that person.

Neo1010115-Aug-15 2:46

Neo10101

15-Aug-15 2:46

There is no need to give me replies like that to every question I ask. My colleague is on vacation.

how to build 3d box

Member 1189993511-Aug-15 5:56

Member 11899935

11-Aug-15 5:56

how to build 3d box in java?

Re: how to build 3d box

Richard MacCutchan11-Aug-15 6:20

Java - Calculation in NEW array

11-Aug-15 6:20

This is another non-question. Please follow the link I gave you below and read it carefully.

Re: how to build 3d box

Neo1010115-Aug-15 2:46

Neo10101

15-Aug-15 2:46

It looks like I'm not the only one you show this autistic behavior towards. Bye.

Frankie124511-Aug-15 5:36

Re: Java - Calculation in NEW array

11-Aug-15 5:36

Hey All,

Working on a project to create an array holding double type data then squaring each element into a new array. Can someone help explain how to store the calculations into a new array? Thanks!

public class Problem_3{
    public static void main(String[] args){
        double[] myList = {1.2,4.7,3.9,4.0};

        //Print all the array elemts
        for (int i = 0; i < myList.length; i++){
            System.out.println(myList[i]+" ");}

            //Square all elements of the array into a new array
            
            for (int i=0; i<myList.length; i++){
              double[] square = myList[i]* myList[i];}

        

        }
    }

Richard MacCutchan11-Aug-15 6:15

11-Aug-15 6:15

Java

double[] square = myList[i]* myList[i];

... does not mean anything. you are trying to declare an array but without creating anything more than a number. Did you go through the tutorials I gave you the links for? They expalin how to create arrays, store and update the content, copy them to new arrays etc.

BTW what you need is:

Java

// create a new array of the correct size
double[] square = new double[myList.length];

// for each element in the original array
for (int i=0; i<myList.length; i++){
    // calculate the square of the value, and store
    // it in the appropriate cell of the array of squares.
    square[i] = myList[i] * myList[i]; // store th
}

Delimiters

Member 107286679-Aug-15 10:58

Member 10728667

9-Aug-15 10:58

How do I separate my input with a tokenizer and delimiter?

Java

import java.io.BufferedWriter;
import java.io.FileWriter;

import javax.swing.JFrame;
import javax.swing.JPanel;

/*******************************************************************************************
Program Name: ClientInformation.java
Programmer's Name: Elizabeth Conklin
Program Description: This program will accept user input and save the input to a file.
*******************************************************************************************/
public class WClientTest {

    public static void main(String[] args) {

        WClient myWClient = new WClient();
        myWClient.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        myWClient.setSize(650, 175);
        myWClient.setTitle("Client Information");
        myWClient.setVisible(true); 
    }
}

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

import java.io.*;
import java.util.ArrayList;
import java.util.StringTokenizer;

public class WClient extends JFrame {

    JLabel labelName;
    JLabel labelID;
    JLabel labelStartingBalance;
    JLabel labelClosingBalance;
    JTextField textName;
    JTextField textID;
    JTextField textStartingBalance;
    JTextField textClosingBalance;
    JButton buttonSave;

    public WClient() {
        setLayout(new GridLayout(0,4));

        labelName = new JLabel("Client Name: ");
        add(labelName);
        textName = new JTextField(10);
        add(textName);
        labelID = new JLabel("Client ID: ");
        add(labelID);
        textID = new JTextField(10);
        add(textID);
        labelStartingBalance = new JLabel("Starting Balance: ");
        add(labelStartingBalance);
        textStartingBalance = new JTextField(10);
        add(textStartingBalance);
        labelClosingBalance = new JLabel("Closing Balance: ");
        add(labelClosingBalance);
        textClosingBalance = new JTextField(10);
        add(textClosingBalance);
        buttonSave = new JButton("SAVE");
        add(buttonSave);

        event e = new event();
        buttonSave.addActionListener(e);}

    public class event implements ActionListener{
        public void actionPerformed(ActionEvent e) {
                try {
                    String name = textName.getText();
                    String ID = textID.getText();
                    String startingBalance = textStartingBalance.getText();
                    String closingBalance = textClosingBalance.getText();

                    textName.setText("");
                    textID.setText("");
                    textStartingBalance.setText("");
                    textClosingBalance.setText("");

                    BufferedWriter outfile = new BufferedWriter(new FileWriter("client.txt", true));

                    outfile.write(name);
                    outfile.write(ID);
                    outfile.write(startingBalance);
                    outfile.write(closingBalance);
                    outfile.close();}
                catch (Exception ex) {
                }
            }
        }{;
    }
}

modified 9-Aug-15 22:32pm.

Re: Delimiters

Richard MacCutchan10-Aug-15 0:56

10-Aug-15 0:56

Just write your own control character after each data item. You could use commas which will give you a CSV file that you can check by loading into Excel, or using a library method that understands .csv format.

Java Bubble Sort

Frankie12457-Aug-15 5:00

7-Aug-15 5:00

I recently did a project that asked the user to input a certain number of elements and then sort those in descending order.

I want to change it where there is no user input if the knowledge of the array is already been established for 10 integers in random order. Then sort them in descending order. 9876...etc

import java.util.Scanner;

class BubbbleHW {
  public static void main(String []args) {
    int num,
    int i,
    int j,
    int temp;
/*This will no longer be needed    
Scanner input = new Scanner(System.in);


  System.out.println(&quot;Enter the number of elements to sort:&quot;);
    num = input.nextInt();
This will no longer be needed*/

    int array[] = new int[num];
//Do I change  int array[] = new int [9]

//    System.out.println(&amp;quot;Enter &amp;quot; + //num + &amp;quot; elem,ents: &amp;quot;);

    for (i = 0; i &amp;lt; num; i++)
      array[i] = input.nextInt();

    for (i = 0; i &amp;lt; ( num - 1 ); i++) {
      for (j = 0; j &amp;lt; num - i - 1; j++) {
        if (array[j] &amp;lt; array[j+1])
        {
          temp = array[j];
          array[j] = array[j+1];
          array[j+1] = temp;
        }
      }
    }

    System.out.println(&amp;quot;Decended order of elemtns&amp;quot;);

    for (i = 0; i &amp;lt; num; i++)
      System.out.println(array[i]);
  }
}&lt;/pre&gt;</pre>

Richard MacCutchan7-Aug-15 6:21

7-Aug-15 6:21

And what is the question?

Frankie12457-Aug-15 6:37

7-Aug-15 6:37

Before the array was populated by
num = input.nextInt();

//so if the user entered 7 then the variable num before would become 7
int array[] = new int[num];

//Do I just need to change the array to this
int array[] = new int[9];

What do I need to change to that the array isn't being populated by the user input anymore but by an array that consists of 10 already known integers (0-9). I do not want to type out each integer such as int array[] = new int[0,1,3....]

Richard MacCutchan7-Aug-15 21:09

7-Aug-15 21:09

Yes, you just instantiate an array of the length you want, and use the Java Random[^] class to generate the values. Something like:

Java

int[] array = new int[9];
for (int i = 0; i < 9; ++i)
{
    array[i] = // next random generated integer
}

Frankie12459-Aug-15 9:33

9-Aug-15 9:33

Thnks for the help,

I'm still having issue with the output if anyone could continue to help with this problem. I want the program to generate 10 random integers and then sort them in descending order.

import java.util.Scanner;

class BubbbleHW {
  public static void main(String []args) {
    int i, j, temp;
    int array[] = new int[9];

    for (i = 0; i < array.length; i++)
      array[i] = (int) Math.random()*9;

    for (i = 0; i < ( array.length - 1 ); i++) {
      for (j = 0; j < array.length - i - 1; j++) {
        if (array[j] < array[j+1])
        {
          temp = array[j];
          array[j] = array[j+1];
          array[j+1] = temp;
        }
    }
    System.out.println(array);
}
    }

}

Richard MacCutchan10-Aug-15 0:54

10-Aug-15 0:54

A couple of obvious errors first:

Java

array[i] = (int) Math.random()*9;

You are casting the result of Math.random to an integer and multiplying the result by 9. But the return value of Math.random is a double greater than 0.0 and less than 1.0, so the integer result will always be zero. You need to do the multiplication first, thus:

Java

array[i] = (int)(Math.random() * 9);

Java

System.out.println(array);

This statement makes no sense, a primitive type or array has no toString method so you cannot use a statement like this to print its contents, you need to traverse the array and print each value, like:

Java

for (i = 0; i < array.length - 1; i++) {
    System.out.println(array[i]);
}

Now you should be able to see that your sort algorithm will not work. You need to check if the first element is greater than the second before swapping them. You also need a flag to check when no more values are out of order. I would use a while, or do/while loop with a boolean flag that can be set at the beginning, and reset every time an out of order pair is found. Try writing it down in your native language first so you understand the logic, and then write the actual code.

Frankie124510-Aug-15 3:22

10-Aug-15 3:22

Thank you! I looked over the errors and was able to resolve the problems you described. Sure these errors seem basic but I am trying to teach myself at the moment.

Thanks again!

Richard MacCutchan10-Aug-15 3:34