hg/apidesign: samples/visitor/21-clientprovider/src-api3.0/org/apidesign/visitor/Language.java@40cabcdcd2be

     1 package org.apidesign.visitor;

     3 public final class Language {

     4     private Language() { }

     6     public interface Expression {

     7         public abstract void visit(Visitor v);

     8     }

     9     public interface Plus extends Expression {

    10         public Expression getFirst();

    11         public Expression getSecond();

    12     }

    13     public interface Number extends Expression {

    14         public int getValue();

    15     }

    16     /** @since 2.0 */

    17     public interface Minus extends Expression {

    18         public Expression getFirst();

    19         public Expression getSecond();

    20     }

    22     // BEGIN: visitor.clientprovider.v3

    23     /** @since 3.0 */

    24     public interface Real extends Expression {

    25         public double getValue();

    26     }

    27     public static abstract class Visitor {

    28         Visitor() {}

    31         /** @since 3.0 */

    32         public static Visitor create(Version30 v) {

    33             return create30(v);

    34         }

    36         /** @since 3.0 */

    37         public interface Version30 {

    38             public boolean visitUnknown(Expression e);

    39             public void visitPlus(Plus s);

    40             public void visitMinus(Minus s);

    41             public void visitReal(Real r);

    42         }

    44         /** @since 3.0 */

    45         public abstract void dispatchReal(Real r);

    47     // FINISH: visitor.clientprovider.v3

    48         /** @since 2.0 */

    49         public static Visitor create(Version20 v) {

    50             return create20(v);

    51         }

    53         /** @since 2.0 */

    54         public interface Version20 extends Version10 {

    55             public void visitMinus(Minus m);

    56         }

    59         /** @since 2.0 */

    60         public abstract void dispatchNumber(Number n);

    62         public static Visitor create(Version10 v) {

    63             return create10(v);

    64         }

    66         public interface Version10 {

    67             public boolean visitUnknown(Expression e);

    68             public void visitPlus(Plus s);

    69             public void visitNumber(Number n);

    70         }

    72         public abstract void dispatchPlus(Plus p);

    73         public abstract void dispatchMinus(Minus m);

    74     }

    76     // BEGIN: visitor.clientprovider.dispatch.v3.l1

    77     static Visitor create10(final Visitor.Version10 v) {

    78         return new Visitor() {

    79             @Override

    80             public void dispatchPlus(Plus p) {

    81                 v.visitPlus(p);

    82             }

    84             @Override

    85             public void dispatchNumber(Number n) {

    86                 v.visitNumber(n);

    87             }

    89             @Override

    90             public void dispatchMinus(Minus m) {

    91                 if (v.visitUnknown(m)) {

    92                     m.getFirst().visit(this);

    93                     m.getSecond().visit(this);

    94                 }

    95             }

    97             @Override

    98             public void dispatchReal(Real r) {

    99                 v.visitUnknown(r);

   100             }

   101         };

   102     }

   103     // END: visitor.clientprovider.dispatch.v3.l1

   104     // BEGIN: visitor.clientprovider.dispatch.v3.l2

   105     static Visitor create20(final Visitor.Version20 v) {

   106         return new Visitor() {

   107             @Override

   108             public void dispatchPlus(Plus p) {

   109                 v.visitPlus(p);

   110             }

   112             @Override

   113             public void dispatchNumber(Number n) {

   114                 v.visitNumber(n);

   115             }

   117             @Override

   118             public void dispatchMinus(Minus m) {

   119                 v.visitMinus(m);

   120             }

   122             @Override

   123             public void dispatchReal(Real r) {

   124                 v.visitUnknown(r);

   125             }

   126         };

   127     }

   128     // END: visitor.clientprovider.dispatch.v3.l2

   129     // BEGIN: visitor.clientprovider.dispatch.v3.l3

   130     static Visitor create30(final Visitor.Version30 v) {

   131         return new Visitor() {

   132             @Override

   133             public void dispatchReal(Real r) {

   134                 v.visitReal(r);

   135             }

   137             @Override

   138             public void dispatchNumber(final Number n) {

   139                 class RealWrapper implements Real {

   140                     public double getValue() {

   141                         return n.getValue();

   142                     }

   143                     public void visit(Visitor v) {

   144                         n.visit(v);

   145                     }

   146                 }

   147                 v.visitReal(new RealWrapper());

   148             }

   150             @Override

   151             public void dispatchPlus(Plus p) {

   152                 v.visitPlus(p);

   153             }

   155             @Override

   156             public void dispatchMinus(Minus m) {

   157                 v.visitMinus(m);

   158             }

   159         };

   160     }

   161     // END: visitor.clientprovider.dispatch.v3.l3

   162 }

author	Jaroslav Tulach <jaroslav.tulach@apidesign.org>
	Thu, 30 Oct 2014 21:30:10 +0100
changeset 409	40cabcdcd2be
parent 177	67d6dceb1002
permissions	-rw-r--r--