jmultimethod

multimethods for Java using annotations
git clone https://logand.com/git/jmultimethod.git/
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CarTest.java (4148B)

      1 // Copyright (c) 2009, 2015 Tomas Hlavaty All rights reserved.
      2 
      3 // Redistribution and use in source and binary forms, with or without
      4 // modification, are permitted provided that the following conditions
      5 // are met:
      6 
      7 // Redistributions of source code must retain the above copyright
      8 // notice, this list of conditions and the following
      9 // disclaimer. Redistributions in binary form must reproduce the above
     10 // copyright notice, this list of conditions and the following
     11 // disclaimer in the documentation and/or other materials provided
     12 // with the distribution.
     13 
     14 // Neither the name of jmultimethod nor the names of its contributors
     15 // may be used to endorse or promote products derived from this
     16 // software without specific prior written permission.
     17 
     18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     21 // FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     22 // COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     23 // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     24 // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     25 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26 // HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     27 // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
     29 // OF THE POSSIBILITY OF SUCH DAMAGE.
     30 
     31 // http://en.wikipedia.org/wiki/Visitor_pattern
     32 
     33 package jmultimethod;
     34 
     35 public class CarTest {
     36 
     37     interface CarElement {}
     38 
     39     class Wheel implements CarElement {
     40         private String name;
     41         Wheel(String name) {
     42             this.name = name;
     43         }
     44         String getName() {
     45             return this.name;
     46         }
     47     }
     48 
     49     class Engine implements CarElement {}
     50 
     51     class Body implements CarElement {}
     52 
     53     class Car {
     54         CarElement[] elements;
     55         public CarElement [] getElements() {
     56             return elements.clone();
     57         }
     58         public Car() {
     59             this.elements = new CarElement[]
     60                 { new Wheel("front left"), new Wheel("front right"),
     61                   new Wheel("back left") , new Wheel("back right"),
     62                   new Body(), new Engine()};
     63         }
     64     }
     65 
     66     @Multi("visit")
     67     public void visitP(Wheel wheel, @V("print") String mode) {
     68         System.out.println("Visiting "+ wheel.getName() + " wheel");
     69     }
     70 
     71     @Multi("visit")
     72     public void visitP(Engine engine, @V("print") String mode) {
     73         System.out.println("Visiting engine");
     74     }
     75 
     76     @Multi("visit")
     77     public void visitP(Body body, @V("print") String mode) {
     78         System.out.println("Visiting body");
     79     }
     80 
     81     @Multi("visit")
     82     public void visitP(Car car, @V("print") String mode) {
     83         System.out.println("\nVisiting car");
     84         for(CarElement element : car.getElements()) {
     85             visit(element, mode);
     86         }
     87         System.out.println("Visited car");
     88     }
     89 
     90     @Multi("visit")
     91     public void visitD(Wheel wheel, @V("do") String mode) {
     92         System.out.println("Kicking my "+ wheel.getName());
     93     }
     94 
     95     @Multi("visit")
     96     public void visitD(Engine engine, @V("do") String mode) {
     97         System.out.println("Starting my engine");
     98     }
     99 
    100     @Multi("visit")
    101     public void visitD(Body body, @V("do") String mode) {
    102         System.out.println("Moving my body");
    103     }
    104 
    105     @Multi("visit")
    106     public void visitD(Car car, @V("do") String mode) {
    107         System.out.println("\nStarting my car");
    108         for(CarElement element : car.getElements()) {
    109             visit(element, mode);
    110         }
    111         System.out.println("Started car");
    112     }
    113 
    114     protected Multimethod mm = new Multimethod("visit", getClass());
    115 
    116     public void visit(Object any, String mode) {
    117         mm.invoke(this, any, mode);
    118     }
    119 
    120     public void run() {
    121         Car car = new Car();
    122         visit(car, "print");
    123         visit(car, "do");
    124     }
    125 
    126     static public void main(String[] args){
    127         CarTest t = new CarTest();
    128         t.run();
    129     }
    130 }