package org.apidesign.test.visitor;

 import static junit.framework.Assert.*;

 import org.apidesign.visitor.Language.Expression;

 import org.apidesign.visitor.Language.Number;

 import org.apidesign.visitor.Language.Plus;

 import org.apidesign.visitor.Language.Visitor1_0;

 import org.junit.Test;

 public class PrintTest {

     public static class PrintVisitor implements Visitor1_0 {

         StringBuffer sb = new StringBuffer();

         public void visitUnknown(Expression exp) {

             sb.append("unknown");

         }

         public void visitPlus(Plus s) {

             s.getFirst().visit(this);

             sb.append(" + ");

             s.getSecond().visit(this);

         }

         public void visitNumber(Number n) {

             sb.append (n.getValue());

         }

     }

     @Test public void printOnePlusOne() {

         Number one = new Number(1);

         Expression plus = new Plus(one, one);

         PrintVisitor print = new PrintVisitor();

         plus.visit(print);

         assertEquals("1 + 1", print.sb.toString());

     }

     @Test public void printOnePlusTwoPlusThree() {

         Number one = new Number(1);

         Number two = new Number(2);

         Number three = new Number(3);

         Expression plus = new Plus(one, new Plus(two, three));

         PrintVisitor print = new PrintVisitor();

         plus.visit(print);

         assertEquals("1 + 2 + 3", print.sb.toString());

     }

 }