Question

I have 2 separate classes, but they both need to do one thing repetitively, in other words there is a common method. This is the method:

private String createButton (String cls, String value) {
        return "<input type=\"button\" class=\"" + cls + 
                   "\" value=\"" + value + "\" key=\"" + this.id + "\" />";
        }

so this is really just a one line method, so I could copy it into both classes. But I was wondering if there’s a better way of doing that. I really don’t want to have a super class with just that method, obviously. Also, I think it’s silly creating another class just for the button and do: new Button(cls,value), isn’t?

Another option I thought about is to have a utility class for the package, with a mix of helper functions. Does that make sense? Is it being done?

Answer 1

You could use a utility class… but it might become incohesive.

public class Utilities {

    /* What do these methods have in common? */

    public String createButton(...) {
        return "<input type='button' />";
    }

    public double calculateCircumference(Circle c) {
        return circle.getRadius() * 2 * Math.PI;
    }

}

This is the kind of code that leads down the dark road to a God Object.

Instead, consider scoping the purpose and intent of your “utility” class: consider making it a factory – specifically an Abstract Factory so that it retains cohesiveness.

public class HTMLWidgetFactory implements AbstractWidgetFactory<String> { // the interface might be overkill

    /* Oh! This class is clearly used to create HTML controls! */

    public String createButton(...) {
        return "<input type='button' />";
    }

    public String createImage(...) {
        return "<img src='lena.png' />";
    }

}