How can I add Levels to my game with less duplication of code?

I am designing a game with multiple levels. I have a setup class that sets up the board based on the argument it receives, which indicates which level it should set up. Here is the class:

public class BoardState {
    public BoardState(InitialState state) {
        switch (state) {
            case EMPTY:
                setupEmptyState();
                break;
            case INTEGRATIONTEST:
                setupIntegrationTestState();
                break;
            case LEVEL_1:
                setupLevelOne();
                break;
            case LEVEL_2:
                setupLevelTwo();
                break;
            default:
                throw new Error("Invalid level selection");
        }
    }

    private void setupEmptyState() { }

    private void setupIntegrationTestState() { }

    private void setupLevelOne() { }

    private void setupLevelTwo() { }
}

This works fine, but every time I add a new level I have to add code in three places: The InitialState enum which defines the list of accepted states, the switch statement in the constructor, and the body of the class, where I have to add a method to set up the level in question.

How can I refactor this code so that there is less overhead associated with adding a new level?