Java simplifying a repetitive code snippet to a function within ActionListener

Question

I am wondering what is an elegant and effective way of simplifying the following snippet of code. Since I have many more buttons and their mechanics all behave in the same way, the symmetry of the methods, and the alternation from color.green -> color.red suggests there may exist a way of simplifying this down to a function?

I have been scratching my head on this design problem for a while, the way I am coding it seems definitely wrong and cumbersome.

GameFrame Class

public class GameFrame extends JFrame{

// (...)
static void initializeComponents(GameFrame frame, GamePanel GamePanel) {

// (...)
ArrayList<JGradientButton> buttons = new ArrayList<JGradientButton>();
Collections.addAll(buttons, b1,b2,b3,b4,b5);
for(JGradientButton button : buttons) {
            button.addActionListener(new ActionListener() {
                
                @Override
                public void actionPerformed(ActionEvent e) {
                    if(button == b1) {
                        GamePanel.b1Pressed();
                        
                    } else if (button == b2) {
                        GamePanel.b2Pressed();

                        if(GamePanel.removeFlag) {
                            button.color = Color.green;
                        } else {
                            button.color = Color.red;
                        }
                        button.repaint();
                        
                    } else if (button == b3) {
                        GamePanel.b3Pressed();  

                        if(!GamePanel.collisionFlag) {
                            button.color = Color.green;
                        } else {
                            button.color = Color.red;
                        }
                        button.repaint();
                     } else if (button == b4) {
                        GamePanel.b4Pressed();
                        if(!GamePanel.electricFlag) {
                            button.color = Color.green;
                        } else {
                            button.color = Color.red;
                        }
                        button.repaint();
                
                     } else {
                        GamePanel.b5Pressed();
                        if(!GamePanel.gravityFlag) {
                            button.color = Color.green;
                        } else {
                            button.color = Color.red;
                        }
                        button.repaint();
                     }
                } 
            });
        }
// (...)

}

---

I am unsatisfied with the above method since I have many buttons and the code for them alternating takes up easily ~100 lines of code. The symmetry of alternation suggests to me that there might exist a better approach for this design.

I have tried writing a function that takes the buttons list but the fact that we are overriding with actionPerformed confuses me a lot, and I don't know if there actually exists a way of simplifying this.

Answer 1

Any number of ways you might do this, but one might be to take the common state information you need and apply it to a method, for example...

protected void update(JGradientButton button, boolean state, Color trueState, Color falseState) {
    if (state) {
        button.color = trueState;
    } else {
        button.color = falseState;
    }
    button.repaint();
}

And then you might call it using something like...

for (JGradientButton button : buttons) {
    button.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            if (button == b1) {
                GamePanel.b1Pressed();
            } else if (button == b2) {
                GamePanel.b2Pressed();
                update(button, GamePanel.removeFlag, Color.green, Color.red);
            } else if (button == b3) {
                GamePanel.b3Pressed();
                update(button, GamePanel.collisionFlag, Color.green, Color.red);
            } else if (button == b4) {
                GamePanel.b4Pressed();
                update(button, GamePanel.electricFlag, Color.green, Color.red);
            } else {
                GamePanel.b5Pressed();
                update(button, GamePanel.gravityFlag, Color.green, Color.red);
            }
        }
    });

I might also consider looking at what bXPressed is doing and what it might be able to do instead and if the functionality can be handed off to them instead.

You could also make use of the Action API, but the problem is, which flag are you looking at? That would require some kind of delegation lookup to determine the state, so you kind of end up in the same place as you would with the above.