[jira] [Created] (LANG-1241) StringUtils.ordinalIndexOf broken

["Pascal Schumacher (JIRA)" <ji...@apache.org>]

Pascal Schumacher created LANG-1241:
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             Summary: StringUtils.ordinalIndexOf broken
                 Key: LANG-1241
                 URL: https://issues.apache.org/jira/browse/LANG-1241
             Project: Commons Lang
          Issue Type: Bug
          Components: lang.*
    Affects Versions: 3.4
            Reporter: Pascal Schumacher


Quoting rousej from the discussion of [https://github.com/apache/commons-lang/pull/93]

I agree with britter. StringUtils.ordinalIndexOf("aaaaaa", "aa", 2) == 1 would be true because the sequence 'aa' is at every index. There seems to be confusion around this method, but it seems to me the original code had it correct.

{code:java}
int index = lastIndex ? str.length() : INDEX_NOT_FOUND;

do {

if (lastIndex) {

index = CharSequenceUtils.lastIndexOf(str, searchStr, index - 1);

} else {

index = CharSequenceUtils.indexOf(str, searchStr, index + 1);

}
{code}

I'm not sure why StringUtils.ordinalIndexOf("aaaaaa", "aa", 2) == 3 would ever be true.
StringUtils.ordinalIndexOf("aaaaaa", "aa", 2) == 2 is easier to see where it's coming from, but StringUtils.ordinalIndexOf("aaaaaa", "aa", 2) == 1 is still the correct answer, and it also works for other tests. I found my way here because I wanted to use this method in a project, but found that the current release is broken by commit [e5a3039|https://github.com/apache/commons-lang/commit/e5a3039f7a1e727fca40db7357a9191b6a7cf41d] . With the current release if the first index is between 0 and searchStr.length() -1 the method will return the index for ordinal + 1.....in other words the wrong index.

This fact is missed in a test like
assertEquals(3, StringUtils.ordinalIndexOf("aaaaaa", "aa", 2));
/* Note the above test from commit [e5a3039|https://github.com/apache/commons-lang/commit/e5a3039f7a1e727fca40db7357a9191b6a7cf41d] is incorrect since the array of chars begins at 0.*/

The following test should pass, but will fail in the current release due to the broken method:
{code:java}
assertEquals(0, StringUtils.ordinalIndexOf("abaabaab", "ab", 1);
assertEquals(3, StringUtils.ordinalIndexOf("abaabaab", "ab", 2);
assertEquals(6, StringUtils.ordinalIndexOf("abaabaab", "ab", 3);
{code}




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