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  1. import java.util.*;
  2.  
  3. class Example {
  4.     public static void main(String[] args) {
  5.         List<Integer> list = Arrays.asList(1, 2, 3);
  6.  
  7.         multiply(list, 3).stream()
  8.         	.forEach(System.out::println);
  9.     }
  10.  
  11. 	static <E> Collection<E> multiply(Collection<E> source, int count) {
  12. 	    return new AbstractCollection<E>() {
  13. 	        @Override
  14. 	        public int size() {
  15. 	            return count * source.size();
  16. 	        }
  17. 	        @Override
  18. 	        public Iterator<E> iterator() {
  19. 	            return new Iterator<E>() {
  20. 	                final Iterator<E> it = source.iterator();
  21.  
  22. 	                E next;
  23. 	                int i = 0;
  24.  
  25. 	                @Override
  26. 	                public boolean hasNext() {
  27. 	                    return i < size();
  28. 	                }
  29. 	                @Override
  30. 	                public E next() {
  31. 	                    if (hasNext()) {
  32. 	                        if ((i % count) == 0) {
  33. 	                            next = it.next();
  34. 	                        }
  35. 	                        ++i;
  36. 	                        return next;
  37. 	                    } else {
  38. 	                        throw new NoSuchElementException();
  39. 	                    }
  40. 	                }
  41. 	            };
  42. 	        }
  43. 	    };
  44. 	}
  45. }
Success #stdin #stdout 0.18s 320576KB
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https://ideone.com/4lc5Wl
language:
Java (HotSpot 12)
created:
9 years ago
visibility:
public

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