// ********** VisitorDemo.java **********
interface Visitor {
  public void visit(ConcreteElementA e);
  public void visit(ConcreteElementB e);
}
class ConcreteVisitor1 implements Visitor {
  public void visit(ConcreteElementA e) { e.operationA(); }
  public void visit(ConcreteElementB e) { e.operationB(); }
}
class ConcreteVisitor2 implements Visitor {
  public void visit(ConcreteElementA e) { e.operationA(); }
  public void visit(ConcreteElementB e) { e.operationB(); }
}
interface Element { 
  public void accept(Visitor v); 
}
class ConcreteElementA implements Element {
  public void accept(Visitor v) { v.visit(this); }
  public void operationA() {}
}
class ConcreteElementB implements Element {
  public void accept(Visitor v) { v.visit(this); }
  public void operationB() {}
}
public class VisitorDemo {
  private static final int MAX = 100000; 
  public static void main(String args[]) {
    long t1 = System.currentTimeMillis();
    for (int i=0; i<MAX; i++) { 
      ConcreteVisitor1 v1 =  new ConcreteVisitor1();
      ConcreteVisitor2 v2 =  new ConcreteVisitor2();
      ConcreteElementA ea =  new ConcreteElementA();
      ConcreteElementB eb =  new ConcreteElementB();
      ea.accept(v1);
      ea.accept(v2);
      eb.accept(v1);
      eb.accept(v2);
    }
    long t2 = System.currentTimeMillis();
    System.out.print((t2-t1)+" ");
    System.out.flush();
  }
}