How to optimize the class that extends JLabel with Singleton

Question

I have a class that extend JLabel. This is the class:

public class LabelFormat extends JLabel {
    public LabelFormat(String string){
        Font myFont=UtilitySwing.getLabelFont();
        this.setText(string);
        this.setFont(myFont);
    }
}

This is the method in the UtilitySwing class:

public static Font getLabelFont(){
    Toolkit t = Toolkit.getDefaultToolkit();
    Dimension screenSize = t.getScreenSize();

    double width = screenSize.getWidth();
    double height= screenSize.getHeight();
    Font myFont;
    if ((width == 1600.0) && (height == 900.0) || 
            (width == 1440.0) && (height == 900.0) || 
            (width == 1280) && (height== 800) || 
            ((width == 1280) && (height== 768)))
    {
        myFont = new Font("Century Gothic", Font.PLAIN, 14);
    }
    else if((width==1024) && (height ==600))
    {
        myFont = new Font("Century Gothic", Font.PLAIN, 12);
    }
    else if ((width == 1024) && (height== 768))
    {
        myFont = new Font("Century Gothic", Font.PLAIN, 12);
    }
    else if ((width == 800) && (height== 600))
    {
        myFont = new Font("Century Gothic", Font.PLAIN, 11);
    }
    else{
        myFont = new Font("Century Gothic", Font.PLAIN, 11);
    }   
    return myFont;
}

So that class found but for me the code is not very effcient, because if I create 5 label I have this:

LabelFormat label1 = new LabelFormat("Pippo");
LabelFormat label2 = new LabelFormat("Pippo");
LabelFormat label3 = new LabelFormat("Pippo");
LabelFormat label4 = new LabelFormat("Pippo");
LabelFormat label5 = new LabelFormat("Pippo");

Whit this code, I call 5 times the class UtilitySwing to calculate the font of the Label. I thought if is possible to use a singleton pattern to call once the UtilitySwing to calculate the Font.

For this, is possible too create the Font in the main class and set it to all Label but I want to create a jar lib and the user need not worry to set the font.

Answer 1

You could...

Call UtilitySwing.getLabelFont() before you create the labels and set there font properties...

Font font = UtilitySwing.getLabelFont();
LabelFormat label1 = new LabelFormat("Pippo");
label1.setFont(font);
//...

But I'd be trying to put in a factory method or loop to make this easier...

Font font = UtilitySwing.getLabelFont();
LabelFormat label1 = createFormatLabel("Pippo", font);

You could...

Use UIManager.put("Label.font", UtilitySwing.getLabelFont()); which set the font to be used by ALL JLabel s, assuming you want the change to be global

This would lead you onto the idea of maybe creating a custom look and feel delegate which you could provide better control for and only effect the LabelFormat instances instead

You could...

Cache the result...

private static Map<Dimension, Font> mapFonts = new HashMap<>(25);

public static Font getLabelFont() {
    Toolkit t = Toolkit.getDefaultToolkit();
    Dimension screenSize = t.getScreenSize();

    Font font = mapFonts.get(screenSize);
    if (font == null) {

        double width = screenSize.getWidth();
        double height = screenSize.getHeight();
        if ((width == 1600.0) && (height == 900.0)
                        || (width == 1440.0) && (height == 900.0)
                        || (width == 1280) && (height == 800)
                        || ((width == 1280) && (height == 768))) {
            font = new Font("Century Gothic", Font.PLAIN, 14);
        } else if ((width == 1024) && (height == 600)) {
            font = new Font("Century Gothic", Font.PLAIN, 12);
        } else if ((width == 1024) && (height == 768)) {
            font = new Font("Century Gothic", Font.PLAIN, 12);
        } else if ((width == 800) && (height == 600)) {
            font = new Font("Century Gothic", Font.PLAIN, 11);
        } else {
            font = new Font("Century Gothic", Font.PLAIN, 11);
        }

        if (font != null) {
            mapFonts.put(screenSize, font);
        }
    }
    return font;
}

If you think the default screen size might change or...

private static Font font;

public static Font getLabelFont() {

    if (font == null) {

        Toolkit t = Toolkit.getDefaultToolkit();
        Dimension screenSize = t.getScreenSize();

        double width = screenSize.getWidth();
        double height = screenSize.getHeight();
        if ((width == 1600.0) && (height == 900.0)
                        || (width == 1440.0) && (height == 900.0)
                        || (width == 1280) && (height == 800)
                        || ((width == 1280) && (height == 768))) {
            font = new Font("Century Gothic", Font.PLAIN, 14);
        } else if ((width == 1024) && (height == 600)) {
            font = new Font("Century Gothic", Font.PLAIN, 12);
        } else if ((width == 1024) && (height == 768)) {
            font = new Font("Century Gothic", Font.PLAIN, 12);
        } else if ((width == 800) && (height == 600)) {
            font = new Font("Century Gothic", Font.PLAIN, 11);
        } else {
            font = new Font("Century Gothic", Font.PLAIN, 11);
        }           
    }
    return font;
}

If you don't care and just want to save time and not repeat the decision making process more then once...