解释代码，为每一个语句附上详细的注释（Wordle游戏中布局类中方法，JAVA）: private void setFieldColor(JLabel field, Color borderColor, Color fillColor, Color fontColor){ field.setBackground(fillColor); boolean isOpaque = fillColor != null; field.setOpaque(isOpaque); field.setForeground(fontColor); int borderThickness = 2; Border line; line = (borderColor != null) ? BorderFactory.createLineBorder(borderColor, borderThickness) : null; Border margin = new EmptyBorder(0, 18, 0, 0); Border compound = new CompoundBorder(line, margin); field.setBorder(compound); }

这是一个设置Wordle游戏中字母方块属性的方法，具体解释如下：

private void setFieldColor(JLabel field, Color borderColor, Color fillColor, Color fontColor){
    //设置方块的背景颜色为fillColor
    field.setBackground(fillColor);
    //判断fillColor是否为空，如果为空则设置方块不透明
    boolean isOpaque = fillColor != null;
    field.setOpaque(isOpaque);
    //设置方块内字母的颜色为fontColor
    field.setForeground(fontColor);
    //设置边框的粗细为2
    int borderThickness = 2;
    Border line;
    //如果borderColor不为空，则使用指定颜色和粗细创建一个边框
    line = (borderColor != null) ? BorderFactory.createLineBorder(borderColor, borderThickness) : null;
    //设置边框的空白边距
    Border margin = new EmptyBorder(0, 18, 0, 0);
    //创建一个由线条边框和空白边距组成的边框
    Border compound = new CompoundBorder(line, margin);
    //设置方块的边框为线条边框和空白边距组成的边框
    field.setBorder(compound);
}