RFR (JDK11/NIO) 8201276: (fs) Add methods to Files for reading/writing a string from/to a file

Joe Wang huizhe.wang at oracle.com
Fri Apr 27 19:21:01 UTC 2018

Hi Rémi, Alan,

I'm not sure we'd want to replace system dependent line separators with 
'\n'. There are cases as you described where the replacement makes 
sense. However,  there are other cases too. For example, the purpose is 
to read, edit a text file and then write it back. If this is on Windows, 
and if line separators are replaced with '\n', that would cause the 
resulting file not formatted properly in for example Notepad. There are 
cases where users write text files on Windows using Java, and only found 
the lines were not separated in Notepad.

Files.write(Path, Iterable) is also specified to terminate each line 
with the platform's line separator. If readString does the replacement, 
it would be inconsistent.

I would think readString behaves like readAllBytes, that would simply 
read all content faithfully.


On 4/27/2018 4:43 AM, forax at univ-mlv.fr wrote:
> Hi Alan,
> People do not read the documentation.
> So adding something in the documentation about when a method should be used or not is never a solution.
> Here the user want a String and provides a charset so you have no way but to decode the content to substitute the line separator.
> cheers,
> Rémi
> ----- Mail original -----
>> De: "Alan Bateman" <Alan.Bateman at oracle.com>
>> À: "Remi Forax" <forax at univ-mlv.fr>, "Joe Wang" <huizhe.wang at oracle.com>
>> Cc: "nio-dev" <nio-dev at openjdk.java.net>, "core-libs-dev" <core-libs-dev at openjdk.java.net>
>> Envoyé: Vendredi 27 Avril 2018 13:34:12
>> Objet: Re: RFR (JDK11/NIO) 8201276: (fs) Add methods to Files for reading/writing a string from/to a file
>> On 27/04/2018 12:29, Remi Forax wrote:
>>> I think that having a readString that includes OS dependent line separators is a
>>> mistake,
>>> Java does a great job to try to shield the developer from the kind of things
>>> that makes programs behave differently on different platforms.
>>> readString should subtitute (\r)?\n to \n otherwise either people will do a call
>>> replace() which is less efficient or will learn the lesson the hard way.
>>> raw string literal does the same substitution for the same reason.
>> Yes, there are several discussion points around this and somewhat timely
>> with multi-string support.
>> One thing that I think Joe will need in this API is some note to make it
>> clearer what the intended usage is (as I think the intention is simple
>> cases with mostly single lines of text).
>> -Alan.

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