public int cardinality() {
        SparseBitSet current;
        int cardinality;
        do {
            current = sparseBitSetVolatile;
            cardinality = current.cardinality();
        } while (current != sparseBitSetVolatile);
        return cardinality;
    }
public int cardinality ( ) { SparseBitSet current ; int cardinality ; do { current = sparseBitSetVolatile ; cardinality = current . cardinality ( ) ; } while ( current != sparseBitSetVolatile ) ; return cardinality ; }
@return the total number of integers added to the set.