I'm writing an interactive fiction game in java from scratch. I'm currently storing all of my game object references in a hashmap in a singleton called ObjectManager. ObjectManager has a function called get which takes an integer ID and returns the appropriate reference. The problem is that it returns a BaseObject when I need to return subclasses of BaseObject with more functionality.

So, what I've done so far is I've added a getEntity function which returns BaseEntity (which is a subclass of BaseObject). However, when I need the function to return to an object that is a subclass of BaseEntity that has added, required functionality, I will need to make another function. I know there is a better way, but I don't know what it is. I know very little of design patterns, and I'm not sure which one to use here. I tried passing 'class' as a parameter, but that didn't get me anywhere.

public BaseObject get(int ID){
    return (BaseObject)refMap.get(ID);
}

public BaseEntity getEntity(int ID){
    return (BaseEntity)refMap.get(ID);
}

Thanks, java ninjas!