[jira] [Commented] (LANG-1148) StringUtils.isBlank does not work correctly with strings containing non-breakable whitespace characters

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

    [ https://issues.apache.org/jira/browse/LANG-1148?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15295074#comment-15295074 ] 

Pascal Schumacher commented on LANG-1148:
-----------------------------------------

I agree that non-breakable whitespace should be treated as whitespace. For example guava https://github.com/google/guava/blob/8fbeb9038cbe8b382b1ee188ae8459203cd04fb5/guava/src/com/google/common/base/CharMatcher.java#L1217 classifies non-breaking space as whitespace.

Of course there is the compatibility issue, so I guess a change like this should only be done in commons-lang 4.0.

> StringUtils.isBlank does not work correctly with strings containing non-breakable whitespace characters
> -------------------------------------------------------------------------------------------------------
>
>                 Key: LANG-1148
>                 URL: https://issues.apache.org/jira/browse/LANG-1148
>             Project: Commons Lang
>          Issue Type: Bug
>          Components: lang.*
>    Affects Versions: 2.6
>         Environment: Windows 8.1 x64 , Java 1.8, but can be reproduced in any environment with an official Oracle JDK or JRE
>            Reporter: Aleksandr Bogush
>            Priority: Minor
>              Labels: test
>   Original Estimate: 3h
>  Remaining Estimate: 3h
>
> isBlank uses java.lang.Character.isWhitespace(char ch) method, which has not been changed for a long time for backward compatibility. Over the years non-breakable whitespaces were introduced and are now used in some cases. So if we execute the code
> {noformat}org.apache.commons.lang.StringUtils.isBlank("\u00A0"); //returns false
> org.apache.commons.lang.StringUtils.isBlank("\u202F"); //returns false
> org.apache.commons.lang.StringUtils.isBlank("\u2007"); //returns false{noformat}
> we will get 3 falses, which is not right, according to StringUtils.isBlank documentation: {noformat}Checks if a String is whitespace, empty ("") or null.{noformat}
> I suggest fixing it by using regex pattern {noformat}"^[\\p{Z}]*$"{noformat} instead of looping over the string characters. I know that it is a bit less fast than it works now, but it will work much more correctly. I would be glad to do it myself and write unit tests for it, so if you want, please contact me via email alex.bohush@gmail.com
> Additionally, I would modify the documentation itself too, because it does not tell that it returns true when meeting multiple whitespaces.



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