What is the use of action command in event handling? Explain with example.

In Java's event handling model, especially with buttons or menu items, the action command is a String identifier associated with an ActionEvent. It helps determine which component triggered the event when multiple components share the same listener.

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🔍 Why Use Action Commands?

• To distinguish between multiple event sources using a single ActionListener.
• Helpful when different buttons or menu items need different actions, but are handled by the same listener method.

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🧪 Example: Action Command in Use

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

public class ActionCommandExample extends JFrame implements ActionListener {

    JButton btnSave, btnLoad;

    public ActionCommandExample() {
        setTitle("ActionCommand Example");
        setSize(300, 150);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLayout(null);

        // Create buttons
        btnSave = new JButton("Save");
        btnLoad = new JButton("Load");

        // Set positions
        btnSave.setBounds(50, 30, 80, 30);
        btnLoad.setBounds(150, 30, 80, 30);

        // Set action commands (optional if button text is enough)
        btnSave.setActionCommand("saveFile");
        btnLoad.setActionCommand("loadFile");

        // Register action listener
        btnSave.addActionListener(this);
        btnLoad.addActionListener(this);

        // Add buttons to frame
        add(btnSave);
        add(btnLoad);
    }

    // Handle events
    public void actionPerformed(ActionEvent e) {
        String cmd = e.getActionCommand();  // Get action command

        if (cmd.equals("saveFile")) {
            JOptionPane.showMessageDialog(this, "Save button clicked");
        } else if (cmd.equals("loadFile")) {
            JOptionPane.showMessageDialog(this, "Load button clicked");
        }
    }

    public static void main(String[] args) {
        new ActionCommandExample().setVisible(true);
    }
}

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⚙️ How it Works:

• btnSave.setActionCommand("saveFile") sets a custom command.
• In actionPerformed(), getActionCommand() returns "saveFile" or "loadFile".
• Based on the command, the correct action is performed.

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✅ Benefits:

• Clean and scalable code.
• Same listener can handle many components.
• Improves readability when button labels change (you can still use stable commands).

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