Inventory System

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.util.*;

public class InventorySystem extends JFrame {
  // Declare constants
  public static final int NUM_ITEMS = 20;
  public static final int WIDTH = 500;
  public static final int HEIGHT = 500;

  // Declare instance variables
  private JList itemList;
  private DefaultListModel model;
  private JTextField nameField;
  private JTextField serialField;
  private JTextField quantityField;
  private JTextField priceField;
  private JTextField searchField;
  private JButton addButton;
  private JButton updateButton;
  private JButton deleteButton;
  private JButton clearButton;
  private JButton searchButton;
  private ArrayList<Item> items;

  public static void main(String[] args) {
    new InventorySystem();
  }

  public InventorySystem() {
    // Initialize instance variables
    model = new DefaultListModel();
    itemList = new JList(model);
    nameField = new JTextField(10);
    serialField = new JTextField(10);
    quantityField = new JTextField(10);
    priceField = new JTextField(10);
    searchField = new JTextField(10);
    addButton = new JButton("Add");
    updateButton = new JButton("Update");
    deleteButton = new JButton("Delete");
    clearButton = new JButton("Clear");
    searchButton = new JButton("Search");
    items = new ArrayList<Item>();

    // Set up layout
    JPanel panel = new JPanel();
    panel.setLayout(new GridBagLayout());
    GridBagConstraints gc = new GridBagConstraints();

    // Add items to layout
    gc.gridx = 0;
    gc.gridy = 0;
    gc.gridheight = 6;
    gc.weightx = 1;
    gc.weighty = 1;
    gc.fill = GridBagConstraints.BOTH;
    panel.add(new JScrollPane(itemList), gc);

    gc.gridx = 1;
    gc.gridy = 0;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.NONE;
    panel.add(new JLabel("Name: "), gc);

    gc.gridx = 2;
    gc.gridy = 0;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.HORIZONTAL;
    panel.add(nameField, gc);

    gc.gridx = 1;
    gc.gridy = 1;
    gc.gridheight = 1;
     gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.NONE;
    panel.add(new JLabel("Serial Number: "), gc);

    gc.gridx = 2;
    gc.gridy = 1;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.HORIZONTAL;
    panel.add(serialField, gc);

    gc.gridx = 1;
    gc.gridy = 2;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.NONE;
    panel.add(new JLabel("Quantity: "), gc);

    gc.gridx = 2;
    gc.gridy = 2;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.HORIZONTAL;
    panel.add(quantityField, gc);

    gc.gridx = 1;
    gc.gridy = 3;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.NONE;
    panel.add(new JLabel("Price: "), gc);

    gc.gridx = 2;
    gc.gridy = 3;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.HORIZONTAL;
    panel.add(priceField, gc);

    gc.gridx = 1;
    gc.gridy = 4;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.NONE;
    panel.add(addButton, gc);

    gc.gridx = 2;
    gc.gridy = 4;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.HORIZONTAL;
    panel.add(updateButton, gc);

    gc.gridx = 1;
    gc.gridy = 5;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.NONE;
    panel.add(deleteButton, gc);

    gc.gridx = 2;
    gc.gridy = 5;
    gc.gridheight = 1;
    gc.weightx = 0;
     gc.weighty = 0;
    gc.fill = GridBagConstraints.HORIZONTAL;
    panel.add(clearButton, gc);

    gc.gridx = 1;
    gc.gridy = 6;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.NONE;
    panel.add(new JLabel("Search: "), gc);

    gc.gridx = 2;
    gc.gridy = 6;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.HORIZONTAL;
    panel.add(searchField, gc);

    gc.gridx = 3;
    gc.gridy = 6;
    gc.gridheight = 1;
    gc.weightx = 0;
    gc.weighty = 0;
    gc.fill = GridBagConstraints.HORIZONTAL;
    panel.add(searchButton, gc);

    // Set up event handling
    addButton.addActionListener(new AddButtonListener());
    updateButton.addActionListener(new UpdateButtonListener());
    deleteButton.addActionListener(new DeleteButtonListener());
    clearButton.addActionListener(new ClearButtonListener());
    searchButton.addActionListener(new SearchButtonListener());

    // Set up the frame
    setTitle("Inventory System");
    setSize(WIDTH, HEIGHT);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    add(panel);
    setVisible(true);
  }

  private class AddButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      String name = nameField.getText();
      String serial = serialField.getText();
      int quantity = 0;
      double price = 0;
      try {
        quantity = Integer.parseInt(quantityField.getText());
        price = Double.parseDouble(priceField.getText());
      } catch (NumberFormatException ex) {
        JOptionPane.showMessageDialog(null, "Invalid input");
        return;
      }
      Item item = new Item(name, serial, quantity, price);
      items.add(item);
      model.addElement(item);
      nameField.setText("");
      serialField.setText("");
      quantityField.setText("");
      priceField.setText("");
    }
  }

  private class UpdateButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      int index = itemList.getSelectedIndex();
      if (index == -1) {
        JOptionPane.showMessageDialog(null, "No item selected");
        return;
      }
      Item item = items.get(index);
      String name = nameField.getText();
      String serial = serialField.getText();
      int quantity = 0;
      double price = 0;
        try {
        quantity = Integer.parseInt(quantityField.getText());
        price = Double.parseDouble(priceField.getText());
      } catch (NumberFormatException ex) {
        JOptionPane.showMessageDialog(null, "Invalid input");
        return;
      }
      item.setName(name);
      item.setSerial(serial);
      item.setQuantity(quantity);
      item.setPrice(price);
      model.set(index, item);
      nameField.setText("");
      serialField.setText("");
      quantityField.setText("");
      priceField.setText("");
    }
  }

  private class DeleteButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      int index = itemList.getSelectedIndex();
      if (index == -1) {
        JOptionPane.showMessageDialog(null, "No item selected");
        return;
      }
      items.remove(index);
      model.remove(index);
      nameField.setText("");
      serialField.setText("");
      quantityField.setText("");
      priceField.setText("");
    }
  }

  private class ClearButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      items.clear();
      model.clear();
      nameField.setText("");
      serialField.setText("");
      quantityField.setText("");
      priceField.setText("");
    }
  }

  private class SearchButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      String search = searchField.getText();
      boolean found = false;
      for (Item item : items) {
        if (item.getSerial().equalsIgnoreCase(search)) {
          nameField.setText(item.getName());
          serialField.setText(item.getSerial());
          quantityField.setText(Integer.toString(item.getQuantity()));
          priceField.setText(Double.toString(item.getPrice()));
          found = true;
          break;
        }
      }
      if (!found) {
        JOptionPane.showMessageDialog(null, "Item not found");
      }
    }
  }

  private class Item {
    private String name;
    private String serial;
    private int quantity;
    private double price;

    public Item(String name, String serial, int quantity, double price) {
      this.name = name;
      this.serial = serial;
      this.quantity = quantity;
      this.price = price;
    }

    public String getName() {
      return name;
    }

    public void setName(String name) {
      this.name = name;
    }

    public String getSerial() {
      return serial;
    }

    public void setSerial(String serial) {
      this.serial = serial;
    }

    public int getQuantity() {
      return quantity;
    }

    public void setQuantity(int quantity) {
      this.quantity = quantity;
    }
    public double getPrice() {
      return price;
    }

    public void setPrice(double price) {
      this.price = price;
    }

    public String toString() {
      return name + " (" + serial + "): " + quantity + " at $" + price;
    }
  }
}