Problem overriding ArrayList add method

Question

I have a class that is extending Java\'s ArrayList. I\'m currently using Java build 1.6.0_22-b04. Looks like this:

public class TokenSequence extends ArrayList&         


        

Answer 1

create a custom ArrayList class and override the add the method as follows

public class CustomArrayList extends ArrayList{

    @Override
    public boolean add(E e) {
        String temp = (String)e;
        if(temp==null || temp.isEmpty()){
            return false;
        }

        return super.add(e);
    }
}

with this class, following example will add only 1 element and print size as 1

public static void main(String args[]) {
        ArrayList lst = new CustomArrayList();
        lst.add("aaaa");
        lst.add(null);
        lst.add("");
        System.out.println(lst.size());
    }