Adding one plus one in idiomatic java.


abstract class Number{
   private Integer m_number;
   Number(Integer m_number){
      this.m_number=m_number;
   }
   public Integer getInteger(){
      return m_number;
   }
   Number add(Number a,Number b){
     return new Number(new Integer(a.getInteger().intValue()+
                                   b.getInteger().intValue()));
   }
   String toString(){
       return getInteger().toString();
   }
}
class One extends Number{
  static Number cached_one=new Number(Integer.parseInt(BigInteger.ONE.toString())); //cached for efficiency  
  static Number createNumberOne(){
     return cached_one;
  }
}
class Main{
   public static void main(String[] args){
     Number result=One.createNumberOne().add(One.createNumberOne());
     System.out.println(result);  //result.toString() is invoked here
   }
}

>>4
Thanks, originally Number was abstract because I also wanted to implement the Two class and then do some if/switch statement logic in add to find the result.  Also ideally Number would implement the "Addable" interface.  I got lazy though :(.