jtulach@169: package org.apidesign.visitor;
jtulach@169: 
jtulach@169: public final class Language {
jtulach@170: 
jtulach@170:     private Language() {
jtulach@170:     }
jtulach@170: 
jtulach@169:     public static abstract class Expression {
jtulach@170: 
jtulach@170:         Expression() {
jtulach@170:         }
jtulach@170: 
jtulach@169:         public abstract void visit(Visitor v);
jtulach@169:     }
jtulach@170: 
jtulach@169:     public static final class Plus extends Expression {
jtulach@170: 
jtulach@169:         private final Expression first;
jtulach@169:         private final Expression second;
jtulach@170: 
jtulach@169:         public Plus(Expression first, Expression second) {
jtulach@169:             this.first = first;
jtulach@169:             this.second = second;
jtulach@169:         }
jtulach@170: 
jtulach@170:         public Expression getFirst() {
jtulach@170:             return first;
jtulach@170:         }
jtulach@170: 
jtulach@170:         public Expression getSecond() {
jtulach@170:             return second;
jtulach@170:         }
jtulach@170: 
jtulach@169:         @Override
jtulach@170:         public void visit(Visitor v) {
jtulach@266:             if (v instanceof Visitor10) {
jtulach@266:                 ((Visitor10) v).visitPlus(this);
jtulach@170:             } else {
jtulach@170:                 v.visitUnknown(this);
jtulach@170:             }
jtulach@170:         }
jtulach@169:     }
jtulach@170: 
jtulach@169:     public static final class Number extends Expression {
jtulach@170: 
jtulach@169:         private final int value;
jtulach@170: 
jtulach@170:         public Number(int value) {
jtulach@170:             this.value = value;
jtulach@170:         }
jtulach@170: 
jtulach@170:         public int getValue() {
jtulach@170:             return value;
jtulach@170:         }
jtulach@170: 
jtulach@169:         @Override
jtulach@170:         public void visit(Visitor v) {
jtulach@266:             if (v instanceof Visitor10) {
jtulach@266:                 ((Visitor10) v).visitNumber(this);
jtulach@170:             } else {
jtulach@170:                 v.visitUnknown(this);
jtulach@170:             }
jtulach@170:         }
jtulach@169:     }
jtulach@170: 
jtulach@169:     /** @since 2.0 */
jtulach@169:     public static final class Minus extends Expression {
jtulach@169:         private final Expression first;
jtulach@169:         private final Expression second;
jtulach@169:         
jtulach@169:         public Minus(Expression first, Expression second) {
jtulach@169:             this.first = first;
jtulach@169:             this.second = second;
jtulach@169:         }
jtulach@169:         public Expression getFirst() { return first; }
jtulach@169:         public Expression getSecond() { return second; }
jtulach@169:         
jtulach@169:         // BEGIN: visitor.cleanversion.dispatch2
jtulach@169:         public void visit(Visitor v) { 
jtulach@266:             if (v instanceof Visitor20) {
jtulach@266:                 ((Visitor20)v).visitMinus(this);
jtulach@169:             } else {
jtulach@169:                 v.visitUnknown(this);
jtulach@169:             }
jtulach@169:         }
jtulach@169:         // END: visitor.cleanversion.dispatch2
jtulach@169:     }
jtulach@169: 
jtulach@169:     // BEGIN: visitor.cleanversion.v2
jtulach@169:     public interface Visitor {
jtulach@169:         public void visitUnknown(Expression e);
jtulach@170:     }
jtulach@266:     public interface Visitor10 extends Visitor {
jtulach@169:         public void visitPlus(Plus s);
jtulach@169:         public void visitNumber(Number n);
jtulach@169:     }
jtulach@169:     /** @since 2.0 */
jtulach@266:     public interface Visitor20 extends Visitor10 {
jtulach@169:         public void visitMinus(Minus s);
jtulach@169:     }
jtulach@169:     // END: visitor.cleanversion.v2
jtulach@169: }