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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.lang.reflect.Array;
  6. import java.io.*;
  7.  
  8. /* Name of the class has to be "Main" only if the class is public. */
  9. class Ideone
  10. {
  11. 	public static void main (String[] args) throws java.lang.Exception
  12. 	{
  13.         // (4 == 2 + 2) && true
  14.         No<Double> mais = new Galho<Double,Double>(new Soma(), new FolhaNumerica(2), new FolhaNumerica(2));
  15.         No<Boolean> igual = new Galho<Double,Boolean>(new Igualdade(), new FolhaNumerica(4), mais);
  16.         No<Boolean> raiz = new Galho<Boolean,Boolean>(new Conjuncao(), igual, new FolhaBooleana(true));
  17.  
  18.         boolean resultado = raiz.avaliar(); // true
  19.         System.out.println(resultado);
  20. 	}
  21. }
  22.  
  23. interface No<T> {
  24.     T avaliar();
  25. }
  26.  
  27. class FolhaNumerica implements No<Double> {
  28.     double valor;
  29.     public Double avaliar() { return valor; }
  30.     FolhaNumerica(double valor) { this.valor = valor; }
  31. }
  32.  
  33. class FolhaBooleana implements No<Boolean> {
  34.     boolean valor;
  35.     public Boolean avaliar() { return valor; }
  36.     FolhaBooleana(boolean valor) { this.valor = valor; }
  37. }
  38.  
  39. interface Operador<E,S> {
  40.     S aplicar(E[] operandos);
  41.     Class<E> obterClasseOperandos();
  42. }
  43.  
  44. class Soma implements Operador<Double,Double> {
  45.     public String toString() { return "+"; }
  46.     public Double aplicar(Double[] operandos) {
  47.         double ret = 0;
  48.         for ( Double d : operandos )
  49.             ret += d;
  50.         return ret;
  51.     }
  52.     public Class<Double> obterClasseOperandos() { return Double.class; }
  53. }
  54.  
  55. class Conjuncao implements Operador<Boolean,Boolean> {
  56.     public String toString() { return "&&"; }
  57.     public Boolean aplicar(Boolean[] operandos) {
  58.         for ( Boolean b : operandos )
  59.             if ( !b )
  60.                 return false;
  61.         return true;
  62.     }
  63.     public Class<Boolean> obterClasseOperandos() { return Boolean.class; }
  64. }
  65.  
  66. class Igualdade implements Operador<Double,Boolean> {
  67.     public String toString() { return "=="; }
  68.     public Boolean aplicar(Double[] operandos) {
  69.         double primeiro = operandos[0];
  70.         for ( Double d : operandos )
  71.             if ( d != primeiro )
  72.                 return false;
  73.         return true;
  74.     }
  75.     public Class<Double> obterClasseOperandos() { return Double.class; }
  76. }
  77.  
  78. class Galho<E,S> implements No<S> {
  79.     Operador<E,S> op;
  80.     No<E>[] operandos;
  81.  
  82.     public S avaliar() {
  83.         @SuppressWarnings("unchecked")
  84.         E[] array = (E[])Array.newInstance(op.obterClasseOperandos(), operandos.length);
  85.         for ( int i = 0 ; i < array.length ; i++ )
  86.             array[i] = operandos[i].avaliar(); // Avalia cada sub-nó recursivamente
  87.  
  88.         return op.aplicar(array); // Passa os resultados para o operador
  89.     }
  90.  
  91.     Galho(Operador<E,S> op, No<E>... operandos) {
  92.         this.op = op;
  93.         this.operandos = operandos;
  94.     }
  95. }
Success #stdin #stdout 0.06s 380160KB
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https://ideone.com/huzEhI
language:
Java (12.0.1)
created:
10 years ago
visibility:
public

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