package org.apidesign.visitor;

 public final class Language {

     private Language() { }

     // BEGIN: visitor.clientprovider.v1

     public interface Expression {

         public abstract void visit(Visitor v);

     }

     public interface Plus extends Expression {

         public Expression getFirst();

         public Expression getSecond();

     }

     public interface Number extends Expression {

         public int getValue();

     }

     public static abstract class Visitor {

         Visitor() {}

         public static Visitor create(Version1_0 v) {

             return create1_0(v);

         }

         public interface Version1_0 {

             public boolean visitUnknown(Expression e);

             public void visitPlus(Plus s);

             public void visitNumber(Number n);

         }

         public abstract void dispatchPlus(Plus p);

         public abstract void dispatchNumber(Number n);

     }

     // END: visitor.clientprovider.v1

     static Visitor create1_0(final Visitor.Version1_0 v) {

         return new Visitor() {

             @Override

             public void dispatchPlus(Plus p) {

                 v.visitPlus(p);

             }

             @Override

             public void dispatchNumber(Number n) {

                 v.visitNumber(n);

             }

         };

     }

 }