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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10. 	public static void main (String[] args) throws java.lang.Exception
  11. 	{
  12.         // (4 == 2 + 2) && true
  13.         No<Double> mais = new Galho<Double,Double>(new Soma(), new FolhaNumerica(2), new FolhaNumerica(2));
  14.         No<Boolean> igual = new Galho<Double,Boolean>(new Igualdade(), new FolhaNumerica(4), mais);
  15.         No<Boolean> raiz = new Galho<Boolean,Boolean>(new Conjuncao(), igual, new FolhaBooleana(true));
  16.  
  17.         boolean resultado = raiz.avaliar(); // true
  18.         System.out.println(resultado);
  19. 	}
  20. }
  21.  
  22. interface No<T> {
  23.     T avaliar();
  24. }
  25.  
  26. class FolhaNumerica implements No<Double> {
  27.     double valor;
  28.     public Double avaliar() { return valor; }
  29.     FolhaNumerica(double valor) { this.valor = valor; }
  30. }
  31.  
  32. class FolhaBooleana implements No<Boolean> {
  33.     boolean valor;
  34.     public Boolean avaliar() { return valor; }
  35.     FolhaBooleana(boolean valor) { this.valor = valor; }
  36. }
  37.  
  38. interface Operador<E,S> {
  39.     S aplicar(Object[] operandos);
  40. }
  41.  
  42. class Soma implements Operador<Double,Double> {
  43.     public String toString() { return "+"; }
  44.     public Double aplicar(Object[] operandos) {
  45.         double ret = 0;
  46.         for ( Object d : operandos )
  47.             ret += (Double)d;
  48.         return ret;
  49.     }
  50. }
  51.  
  52. class Conjuncao implements Operador<Boolean,Boolean> {
  53.     public String toString() { return "&&"; }
  54.     public Boolean aplicar(Object[] operandos) {
  55.         for ( Object b : operandos )
  56.             if ( !(Boolean)b )
  57.                 return false;
  58.         return true;
  59.     }
  60. }
  61.  
  62. class Igualdade implements Operador<Double,Boolean> {
  63.     public String toString() { return "=="; }
  64.     public Boolean aplicar(Object[] operandos) {
  65.         double primeiro = (Double)operandos[0];
  66.         for ( Object d : operandos )
  67.             if ( (Double)d != primeiro )
  68.                 return false;
  69.         return true;
  70.     }
  71. }
  72.  
  73. class Galho<E,S> implements No<S> {
  74.     Operador<E,S> op;
  75.     No<E>[] operandos;
  76.  
  77.     public S avaliar() {
  78.         List<E> args = new ArrayList<E>();
  79.         for ( No<E> no : operandos )
  80.             args.add(no.avaliar()); // Avalia cada sub-nó recursivamente
  81.         return op.aplicar((E[])args.toArray()); // Passa os resultados para o operador
  82.     }
  83.  
  84.     Galho(Operador<E,S> op, No<E>... operandos) {
  85.         this.op = op;
  86.         this.operandos = operandos;
  87.     }
  88. }
  89.  
Success #stdin #stdout 0.07s 380224KB
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true
https://ideone.com/IgEHLs
language:
Java (12.0.1)
created:
11 years ago
visibility:
public

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