/*
   +----------+     
   | OldBook  |     
   +----------+
   |int year  |  
   +----------+   
*/   

//a predicate to select old books
class OldBook implements ISelect{

  int year;  

  OldBook(int year){
    this.year=year;
  }

  //is the given book written before this year   
  public  boolean select(Object obj){ 
    return (this.year>((Book)obj).year); 
  } 
}