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  1. import java.util.*;
  2. import java.lang.*;
  3. import java.io.*;
  4. import java.util.function.*;
  5.  
  6. class Ideone
  7. {
  8. 	public static void main (String[] args) throws java.lang.Exception
  9. 	{
  10. 		StringUtil.indexOf("hello, world", 'l')
  11. 			.DoIfSuccess(foundIndex -> {
  12. 				System.out.println(String.format("index=%d", foundIndex));
  13. 			});
  14. 	}
  15. }
  16.  
  17. class StringUtil {
  18. 	public static ResultOfIndexOf indexOf(String haystack, char needle) {
  19. 		for (int i = 0; i < haystack.length(); ++i)
  20. 			if (haystack.charAt(i) == needle)
  21. 				return new ResultOfIndexOf(i);
  22. 		return new ResultOfIndexOf();
  23. 	}
  24. }
  25.  
  26. class ResultOfIndexOf {
  27. 	private final boolean isFound;
  28. 	private final int foundIndex;
  29. 	ResultOfIndexOf() {
  30. 		this(false, 0);
  31. 	}
  32. 	ResultOfIndexOf(int foundIndex) {
  33. 		this(true, foundIndex);
  34. 	}
  35. 	private ResultOfIndexOf(boolean isFound, int foundIndex) {
  36. 		this.isFound = isFound;
  37. 		this.foundIndex = foundIndex;
  38. 	}
  39. 	public void DoIfSuccess(Consumer<Integer> postAction) {
  40. 		if (isFound && postAction != null)
  41. 			postAction.accept(foundIndex);
  42. 	}
  43. }
  44.  
Success #stdin #stdout 0.12s 2184192KB
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index=2
https://ideone.com/UKwvxk
qiita - result_of_index_of sample impl 2
language:
Java (HotSpot 12)
created:
5 years ago
visibility:
public

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