How to read from textfile and display specific words(numbers) from that txtfile based on diffrent groups

Question

How to read from a textfile and display specific words(numbers) from that textfile based on different groups?

I have a txt file that contains this:

[computers]
keyboards =3
mouse  =5

[animals]
cow =10
pig =5

The numbers will always be changed by another program.

I want to make a form that can display the like this:

Cars:    3 keyboards/n
         5 mouse

animals 10 cows
        5  pigs

I don`t know how to do that. I know how to read from file but the next...

This is how my frame will look package nioCount;

import java.awt.BorderLayout;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JButton;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class FrameTest extends JFrame {

private JPanel contentPane;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                FrameTest frame = new FrameTest();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the frame.
 */
public FrameTest() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 450, 300);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);

    JButton btnCount = new JButton("Count");
    btnCount.setBounds(80, 202, 89, 23);
    contentPane.add(btnCount);

    JButton btnResetCount = new JButton("Reset");
    btnResetCount.setBounds(268, 202, 89, 23);
    contentPane.add(btnResetCount);

    JTextArea txtrComputers = new JTextArea();
    txtrComputers.setText("Computers:");
    txtrComputers.setBounds(24, 59, 84, 22);
    contentPane.add(txtrComputers);

    JTextArea txtrKeyboards = new JTextArea();
    txtrKeyboards.setText("3 keyboards");
    txtrKeyboards.setBounds(147, 43, 130, 23);
    contentPane.add(txtrKeyboards);

    JTextArea txtrMouses = new JTextArea();
    txtrMouses.setText("10 mouses");
    txtrMouses.setBounds(147, 77, 130, 22);
    contentPane.add(txtrMouses);

    JTextArea txtrAnimals = new JTextArea();
    txtrAnimals.setText("Animals:");
    txtrAnimals.setBounds(24, 133, 84, 22);
    contentPane.add(txtrAnimals);

    JTextArea txtrDogs = new JTextArea();
    txtrDogs.setText("3 Dogs");
    txtrDogs.setBounds(147, 110, 130, 23);
    contentPane.add(txtrDogs);

    JTextArea txtrCats = new JTextArea();
    txtrCats.setText("15 cats");
    txtrCats.setBounds(147, 152, 130, 23);
    contentPane.add(txtrCats);
}

}

and when i press count button it will count for each category..

This is what my .txt file contains:

[phone]
bad=1
good=30

[animals]
bad=10
good=30

Answer 1

A possible way to do this is a BufferedReader:

public class ReadTextFile {

    public static void main(String[] args) {
        BufferedReader br = null;
        try {
            String currentLine;

            br = new BufferedReader(new FileReader("file.txt"));

            while ((currentLine = br.readLine()) != null) {
                System.out.println(currentLine);
                //test for your strings from here
                //("[computers]", etc.)
            }

        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (br != null) {
                    br.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
}

I don't know what exactly you want to do, but I think you would be happier with XML.

Answer 2

We have the following objects to keep track of.

1. Category (i.e. Computer, Animal)
2. Descriptor (i.e. Keyboard, Pig)
3. Count (i.e. 5, 10)

We have the following dependencies.

1. A Category can have 1 or more Descriptors.
2. A Descriptor has one Count.

There are several approaches to doing this, but I'll go with the one easiest based on your description here.

The numbers will always be changed by another program

I assume this means we need to be able to track Descriptor and change it, possibly without knowing what the Category is. For example, an example method of setValue("Keyboard", 10);

We don't know the Keyboard is related to the computer, and searching through all the categories to find the Keyboard is time-intensive.

Since you say you know how to read the file, I'll leave that up to you, and instead describe what to do with pseudocode.

First of all, we need two Maps. For simplicity, I'll use HashMaps.

HashMap<String, ArrayList<String>> categoryToDescriptor = new HashMap<>();
HashMap<String, Integer> descriptorToCount = new HashMap<>();

The first map stores all of our categories, the second map stores all of our counts.

Let's say we take the text input and come across "[Computer]". We need to add this to our category map:

categoryToDescriptor.put("Computer", new ArrayList<String>);

In your case, you'd have a variable to parse out Computer, and all the variables.

After that, we get descriptors and values, such as "keyboard=5"

We do two things with this info. You can parse it out, but I'll hardcode it.

String descriptor = "keyboard";
int count = 5;

categoryToDescriptor.get("Computer").add("keyboard");
descriptorToCount.put("keyboard",5);

We are now mapping categories to a list of descriptors, and descriptors to their associated counts.

Using entryset iteration, we can do something like this to print out all the values.

for (Map.Entry<String, ArrayList<String>> entry : categoryToDescriptor.entrySet()) {
    System.out.println("Category: " + entry.getKey());
    ArrayList<String> listOfDescriptors = entry.getValue();
    for(String descriptor: listOfDescriptors) {
        System.out.println("Descriptor: " + descriptor + " Value: " + descriptorToCount.get(descriptor);)
    }
    System.out.println("");//line feed between categories
}

Additionally, to update a value of a descriptor, all we have to do is:

descriptorToCount.put("keyboard", newValue);