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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. class Tuple<A, B> {
  8. 	private final A fst;
  9. 	private final B snd;
  10. 	public Tuple(A fst, B snd) {
  11. 		this.fst = fst;
  12. 		this.snd = snd;
  13. 	}
  14. 	public A fst() {
  15. 		return fst;
  16. 	}
  17. 	public B snd() {
  18. 		return snd;
  19. 	}
  20. 	public String toString() {
  21. 		return String.format("(%s,%s)", fst, snd);
  22. 	}
  23. }
  24.  
  25. interface Function<A, B> {
  26. 	B apply(A x);
  27. }
  28.  
  29. class IntStr implements Function<Integer, String> {
  30. 	public String apply(Integer x) {
  31. 		return x.toString();
  32. 	}
  33. }
  34.  
  35. class MakeTpl<A> implements Function<A, Tuple<A, A>> {
  36. 	public Tuple<A, A> apply(A x) {
  37. 		return new Tuple(x, x);
  38. 	}
  39. }
  40.  
  41. class Ideone {
  42. 	public static <A, B> List<B> transform(Function<A, B> f, List<A> xs) {
  43. 		List<B> ys = new ArrayList<>(xs.size());
  44. 		for (A x : xs) {
  45. 			ys.add(f.apply(x));
  46. 		}
  47. 		return ys;
  48. 	}
  49.  
  50. 	static <A, B> void test(Function<A, B> f, List<A> xs) {
  51. 		System.out.println(transform(f, xs));
  52. 	}
  53. 	static class MakeChrTpl extends MakeTpl<Character> {}
  54. 	public static void main (String[] args) throws java.lang.Exception {
  55. 		List<Integer> xs = Arrays.asList(1, 2, 3);
  56. 		List<Character> ys = Arrays.asList('a', 'b', 'c');
  57. 		test(new IntStr(), xs);
  58. 		test(new MakeChrTpl(), ys);
  59. 	}
  60. }
Success #stdin #stdout 0.07s 380160KB
comments (?)
stdin 
Standard input is empty
stdout 
[1, 2, 3]
[(a,a), (b,b), (c,c)]
https://ideone.com/jI1tOH
language:
Java (12.0.1)
created:
10 years ago
visibility:
public

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