Call a method when class name not known at compile time

I have a number of sub-games, SubGame1, SubGame2 etc. Each is derived from a SubGame class and implements a static String getDescription() function.

I want to access these descriptions, e.g. SubGame1.getDescription(), SubGame2.getDescription() etc.

However I want to use a code loop and not all the subgames will exist.

How can I call getDescription() for a sub game when I only know the game number. Something like:

St开发者_高级运维ring description = Class.forName(this.getPackageName()+".SubGame"+subGameNo.getDescription();

but that returns: The method getDescription() is undefined for the type Class< capture#5-of ?>

Any ideas?

You can call it, but you have to do it via the java.lang.reflect classes. Class.forName gives you a Class instance. You then call getMethod to get the Method, on which you can then call invoke.

Off the top of my head:

Class cls;
Method getDescription;
String description;

cls = Class.forName(this.getPackageName() + ".SubGame" + subGameNo);
getDescription = cls.getMethod("getDescription");
description = getDescription.invoke(null);

...but you may have to play with the args a bit.

You can use Class.forName() to get the instance of the class.

Then you can call the method using reflection. Code would look something like this

Class<?> clazz = Class.forName(this.getPackageName()+".SubGame"+subGameNo);
Method descriptionMethod = clazz.getMethod("getDescription", new Class[] {});
String value = (String) descriptionMethod .invoke(this, new Object[] {}); 

You could just create a Map of game numbers to game descriptions (map.put(1, SubGame1.getDescription()) and then just grab the description from the map as needed. It's not as dynamic as you may want but it will work.