How to support older Java dependencies after methods have been removed?

Question

I am writing a plugin for Minecraft which uses WorldEdit. There is a class BlockVector3 with methods getBlockX() and getX() which are deprecated and marked for removal, to be replaced by x().

The problem is that if I use the new method, users who are using an older version of WorldEdit will no longer be able to use my plugin. And if I retain the deprecated method, it will soon cease to function with the latest dependency.

I could write two different plugins. However, is there a way to work around this particular issue using reflection or some other introspection?

Answer 1

There are multiple ways to do this.

1. One class per version, tricky but easy.

It's a common way to do it. Mostly, people do an interface like this :

public interface WorldEditAdapter {
   void load();
   void doSomething(double x, double y, double z);
}

Then, create a new class for each version like this:

public class WorldEdit3 implements WorldEditAdapter {
   public void load() {
       // load everything related to WorldEdit 3
   }
}

public class WorldEdit4 implements WorldEditAdapter {
   public void load() {
       // load everything related to WorldEdit 4
   }
}

Then, in the onEnable(), firstly check for which version is used, then instanciate it with new WorldEdit3() for example, then save it as WorldEditAdapter. Now, your full plugin will use WorldEditAdapter.

---

About how to use method not available, if you don't have compilation plugin, maybe you can import multiple file to "fake" the existance of method for 2 versions. This could be tricky.

You can also use reflection as you mentionned. It's not preferable. To use it, do:

myObject.getClass().getDeclaredMethod("getX").invoke(myObject); // equivalent of myObject.getX();

Static call of method:

MyClass.class.getDeclaredMethod("myMethod").invoke(null); // equivalent of MyClass.myMethod();

2. Gradle/Maven: sub projects.

With gradle and maven it would be easier. You can do solution 1 but by putting the WorldEdit3 in different subproject loaded by the main one. It would be easier to manage, but it's not your case.