Github user rikles commented on a diff in the pull request:
https://github.com/apache/commons-lang/pull/75#discussion_r30461235
--- Diff: src/main/java/org/apache/commons/lang3/StringUtils.java ---
@@ -3277,6 +3277,164 @@ public static String substringBetween(final String
str, final String open, final
return list.toArray(new String[list.size()]);
}
+ /**
+ * <p>Split a String into an array, using an array of fixed string
lengths.</p>
+ *
+ * <p>If not null String input, the returned array size is same as the
input lengths array.</p>
+ *
+ * <p>A null input String returns {@code null}.
+ * A {@code null} or empty input lengths array returns an empty array.
+ * A {@code 0} in the input lengths array results in en empty
string.</p>
+ *
+ * <p>Extra characters are ignored (ie String length greater than sum
of split lengths).
+ * All empty substrings other than zero length requested, are returned
{@code null}.</p>
+ *
+ * <pre>
+ * StringUtils.splitByLength(null, *) = null
+ * StringUtils.splitByLength("abc") = []
+ * StringUtils.splitByLength("abc", null) = []
+ * StringUtils.splitByLength("abc", []) = []
+ * StringUtils.splitByLength("", 2, 4, 1) = [null, null, null]
+ *
+ * StringUtils.splitByLength("abcdefg", 2, 4, 1) = ["ab", "cdef",
"g"]
+ * StringUtils.splitByLength("abcdefghij", 2, 4, 1) = ["ab", "cdef",
"g"]
+ * StringUtils.splitByLength("abcdefg", 2, 4, 5) = ["ab", "cdef",
"g"]
+ * StringUtils.splitByLength("abcdef", 2, 4, 1) = ["ab", "cdef",
null]
+ *
+ * StringUtils.splitByLength(" abcdef", 2, 4, 1) = [" a", "bcde",
"f"]
+ * StringUtils.splitByLength("abcdef ", 2, 4, 1) = ["ab", "cdef",
" "]
+ * StringUtils.splitByLength("abcdefg", 2, 4, 0, 1) = ["ab", "cdef",
"", "g"]
+ * StringUtils.splitByLength("abcdefg", -1) = {@link
IllegalArgumentException}
--- End diff --
It's true that negative numbers could be easily promotes to 0.
But here, it's not like in `StringUtils.split(String, String, int)` where
the int value indicate the maximum number of results we want. It's very common
that passing a zero or negative value mean _no limit_.
Here, we request several "column" lengths. I thought it was natural and
easier to consider negative lengths as a coding mistake.
I even wondered if we could interpret negative values like :
* _unlimited length_. But what about
`StringUtils.splitByLength("abcdefg", -1, 2, -1, -1)` ... ?
* _backward move_ like `StringUtils.splitByLength("abcde", 3, -2, 4) =
["abc", "bcde"]`. But what about `StringUtils.splitByLength("abcdef", 1, -4,
3)` ... ?
I don't know what to think about it...
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