package a2Safecasting;
/***********************************************
 *  Coffee, done right
 ***********************************************/

import tester.*;

interface Drink {
  // Is this drink the same as that drink?
  Boolean same(Drink that);

  // Is this drink a tea?
  Boolean isTea();
  // Is this drink a coffee?
  Boolean isCoffee();
  // Is this drink a latte?
  Boolean isLatte();

  // Cast this drink to a tea
  Tea toTea();
  // Cast this drink a coffee
  Coffee toCoffee();
  // Cast this drink to a latte
  Latte toLatte();
}

abstract class ADrink {
  public Boolean isTea() { return false; }
  public Boolean isCoffee() { return false; }
  public Boolean isLatte() { return false; }


  // Turn you into a Tea
  public Tea toTea() {
    throw new RuntimeException("What were you thinking!");
  } 
  // Turn you into a Coffee
  public Coffee toCoffee() {
    throw new RuntimeException("What were you thinking!");
  } 
  // Turn you into a Latte
  public Latte toLatte() {
    throw new RuntimeException("What were you thinking!");
  }

}

class Tea extends ADrink implements Drink {

  // Is this tea the same as that drink?
  public Boolean same(Drink that) {
    if (that.isTea())
      return this.sameTea(that.toTea());
    else 
      return false;
  }

  // Is this tea drink a tea?
  public Boolean isTea() {
    return true;
  }  
  
  // Turn you into a Tea
  public Tea toTea() {
    return this;
  } 

  // Is this tea drink the same as the given tea drink?
  public boolean sameTea(Tea that){
    return true;
  }
}

class Coffee extends ADrink implements Drink {

  // Is this coffee the same as that drink?
  public Boolean same(Drink that) {
    if (that.isCoffee())
      return this.sameCoffee(that.toCoffee());
    else
      return false;
  }

  // Is this coffee drink a coffee?
  public Boolean isCoffee() { 
    return true;
  }
  
  // Turn you into a Coffee
  public Coffee toCoffee() {
    return this;
  }

  // Is this coffee drink the same as the given coffee drink?
  public boolean sameCoffee(Coffee that){
    return true;
  }
}

class Latte extends Coffee {

  // Is this latte the same as that drink?
  public Boolean same(Drink that) {
    if (that.isLatte())
      return this.sameLatte(that.toLatte());
    else
      return false;
  }

  // Is this latte drink a coffee?
  public Boolean isCoffee() {
    return false;
  }

  // Is this latte drink a latte?
  public Boolean isLatte() {
    return true;
  }

  // Turn you into a Latte
  public Latte toLatte() {
    return this;
  }

  // Is this latte drink the same as the given latte drink?
  public Boolean sameLatte(Latte that) {
    return false;
  }
}

public class ExamplesCoffeeSafeCasting {
  ExamplesCoffeeSafeCasting(){}

  public static ExamplesCoffeeSafeCasting examplesInstance = 
      new ExamplesCoffeeSafeCasting();

  Drink t = new Tea();
  Drink c = new Coffee();
  Drink l = new Latte();

  public Boolean testSameDrink(Tester t) {
    return t.checkExpect(this.t.same(this.t), true)
        && t.checkExpect(this.c.same(this.c), true)
        && t.checkExpect(this.t.same(this.c), false)
        && t.checkExpect(this.c.same(this.t), false);
  }
  public Boolean testSameCoffee(Tester t) {
    return t.checkExpect(this.l.same(this.c), false)  // works!
        && t.checkExpect(this.c.same(this.l), false); // still works!
  }

  // run all tests
  public static void main(String[] argv){
    ExamplesCoffeeSafeCasting e = 
        new ExamplesCoffeeSafeCasting();
    Tester.runReport(e, false, false);
  }
}