Java, clever way to replace "if not null" statement?

I have a Vector full of longs.

I would like to be able to always call getFirstElement() on a Vector and then perform an action, let's say addToOther开发者_如何学编程Vector(). I want to be able to not worry whether or not there is actually a value to return from my original vector. I think I could do it by overriding addToOtherVector() like so:

//Code to be called when my first vector is not empty
public void addToOtherVector(long s){
    othervector.add(s);
}

//Code to be called when my first vector IS empty
public void addToOtherVector(something???){
    //does nothing
}

but I'm not sure what i need to do for the something, as it won't accept null as a parameter?

The reason I am doing this is because I don't wish to have to check the size of the vector each time I try to retrieve

Just override the method with a base class. Since Number is the base class to Long, Integer, etc. just use that one :

//Code to be called when my first vector is not empty
public void addToOtherVector(long s){
   othervector.add(s);
}

//Code to be called when my first vector IS empty
public void addToOtherVector(Number s){
   if (s == null) {
       return;
   }
   othervector.add(((Number) s).longValue());
}

import java.util.Vector;
public class Main {

    static Vector otherVector = new Vector();

    public static void main(String[] args) {

        Vector originalVector = new Vector();
        originalVector.add(1);
        originalVector.add(null);
        originalVector.add(2);

        for (Object obj : originalVector) {
            addToOtherVector(obj);
        }
    }

    public static void addToOtherVector(long s) {
        otherVector.add(s);
        System.out.println("adding " + s + " to vector");
    }

    public static void addToOtherVector(Object obj) {
        System.out.println("not adding " + obj + " to vector");
    }
}