InputEvent.BUTTON2_MASK has the following syntax.
public static final int BUTTON2_MASK
In the following code shows how to use InputEvent.BUTTON2_MASK field.
/*www .ja v a 2 s .c om*/ import java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.InputEvent; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.SwingUtilities; public class Main { public static void main(String args[]) { JFrame frame = new JFrame("Button Sample"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JButton button = new JButton("Select Me"); ActionListener actionListener = new ActionListener() { public void actionPerformed(ActionEvent actionEvent) { System.out.println("I was selected."); } }; MouseListener mouseListener = new MouseAdapter() { public void mousePressed(MouseEvent mouseEvent) { int modifiers = mouseEvent.getModifiers(); if ((modifiers & InputEvent.BUTTON1_MASK) == InputEvent.BUTTON1_MASK) { System.out.println("Left button pressed."); } if ((modifiers & InputEvent.BUTTON2_MASK) == InputEvent.BUTTON2_MASK) { System.out.println("Middle button pressed."); } if ((modifiers & InputEvent.BUTTON3_MASK) == InputEvent.BUTTON3_MASK) { System.out.println("Right button pressed."); } } public void mouseReleased(MouseEvent mouseEvent) { if (SwingUtilities.isLeftMouseButton(mouseEvent)) { System.out.println("Left button released."); } if (SwingUtilities.isMiddleMouseButton(mouseEvent)) { System.out.println("Middle button released."); } if (SwingUtilities.isRightMouseButton(mouseEvent)) { System.out.println("Right button released."); } System.out.println(); } }; button.addActionListener(actionListener); button.addMouseListener(mouseListener); frame.add(button, BorderLayout.SOUTH); frame.setSize(300, 100); frame.setVisible(true); } }