Enable a JButton when some component changed its border color [closed]

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My goal is to enable a JButton only when some JTextFields and JComboBox change its border color from red to green.
These components are included in three different JPanel.
I try to create a function that reads all components in a JPanel but, when I’m going to compared the colors, the program returns me that I’m casting the variables in a bad way.
Below there’s my function.
Can someone help me?

    public static boolean countBoards(JPanel panel){
        boolean red = false;
        
        for(Component control : panel.getComponents())
        {
            if(control instanceof JTextField)
            {
                JTextField ctrl = (JTextField) control; 
                Color lineColor = ((LineBorder)ctrl.getBorder()).getLineColor();
            
                if(lineColor.equals(Color.red))
                    red = true;                
            }  
            else if(control instanceof JComboBox)
            {
                JComboBox ctr = (JComboBox) control; 
                Color lineColor = ((LineBorder)ctr.getBorder()).getLineColor();
            
                if(lineColor.equals(Color.red))
                    red = true;               
            }
        }                 
        
        return red;
    }

Answer

When you change the border of a component, a property listener will be fired. You can register a property listener to the combobox/textfield and enable/disable the button according to the new border.

An example:

@Test
public void test() {
    JButton myButton = new JButton();
    JComboBox<String> combo = new JComboBox<>();
    combo.addPropertyChangeListener("border", e -> {
        if (e.getNewValue() != null && e.getNewValue() instanceof LineBorder) {
            LineBorder border = (LineBorder) e.getNewValue();
            myButton.setEnabled(border.getLineColor().equals(Color.green));
        }
    });
    assertTrue(myButton.isEnabled(), "Button should be initially enabled.");

    combo.setBorder(BorderFactory.createLineBorder(Color.red));
    assertFalse(myButton.isEnabled(), "Button should be disabled when red line border occurs.");

    combo.setBorder(BorderFactory.createLineBorder(Color.green));
    assertTrue(myButton.isEnabled(), "Button should be enabled when green line border occurs.");
}


Source: stackoverflow