CODEWITHSUNDEEP
javastaticoverridingabstractutility
Tom To
Tom To

Reputation: 13

Work around for overriding abstract static method in Java?

Working on a customised JSON Converter to comply with company standard (basically adding many tags and handling for enum). The converter only works for objects with a public nullary constructor, so it had some problem with those objects enhanced by Spring and it has to workaround by something like this: ((Advised) advised).getTargetSource().getTargetClass();

The final product works pretty well, but having Spring library imported makes it a bit too large and we decided to have 2 different classes, one for projects which are using Spring and the other for those aren't.

Ideally, the 2 Converters should look something like this:

JsonConverter.java

public class JsonConverter {
    // public static toObject(){...}
    // public static toJSON(){...}
    // other methods
    protected static resolveTargetClass(Object obj){return obj.getClass();}
}

SpringJsonConverter.java

public class SpringJsonConverter extends JsonConverter {
    protected static resolveTargetClass(Object obj){
        if(obj instanceof Advised)
            ((Advised) obj).getTargetSource().getTargetClass();
        return obj.getClass();
    }
}

And just as everyone knows, this won't work as resolveTargetClass is static and not overridable. Is there any elegant way to do this? I would like to keep everything static as this converter had already been used by many projects and fixing it would cost so much time.

Upvotes: 1

Views: 127

Answers (1)

GhostCat
GhostCat

Reputation: 140603

Seriously: don't use static here.

static leads to tight coupling between classes, and as you figured yourself: it "kills" polymorphism. In that sense: it is the opposite of good practices. Not always, but as soon as it hampers your ability to create a good design, static is obviously the wrong approach.

Thus: simply drop the static keyword from your current code. Yes, that will cost you now. But it enables you to do the right thing in the future.

Upvotes: 3

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