I think there is a work-around, use list() and flatMap() should get you what
you needed.
The API is designed to walk a tree where you suppose to have access with. If OS
level cause an IOException, that need to be dealt with. Acknowledged that
exception handling is not a strong suite in Stream API, developer will need to
do some work.
Files.find() also allows you to get entries and filter out by permission. What
you can do is make sure you have permission on the top level, then call find
with maxDepth 1 to only get entries on that directory.
Combined with flatMap(), you should be able to get what you want. Try the
following code to see if it works for you.
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Stream;
import java.io.IOException;
public class ListCanRead {
static Stream<Path> walkReadable(Path p) {
if (Files.isReadable(p)) {
if (Files.isDirectory(p)) {
try {
return Stream.concat(Stream.of(p), Files.list(p));
} catch (IOException ioe) {
return Stream.of(p);
}
} else {
return Stream.of(p);
}
}
return Stream.of(p);
}
public static void main(String[] args) throws IOException {
System.out.println("List directory: " + args[0]);
walkReadable(Paths.get(args[0])).flatMap(ListCanRead::walkReadable)
.forEach(System.out::println);
Files.walk(Paths.get(args[0]))
.forEach(System.out::println); // Could throw AccessDeniedException
}
}
Cheers,
Henry
On May 24, 2016 at 4:48:30 PM, Gilles Habran (gilleshab...@gmail.com) wrote:
> Good morning,
>
> well I would like to be able to manage the outcome of the processing myself
> and not get an exception in a part where I have no control.
>
> For example, I would expect to get an exception when I tried to read a file
> where I don't have the permission. I would not expect to get an exception
> when Java creates the Stream.
>
> Maybe I am the only one to have a problem with this ? I don't know but it
> feels strange to be forced to execute a software with root permissions
> where I don't even plan to read file I cannot read because of lack of
> permissions.
>
> For me, we should be able to test the attributes of a file and depending on
> the result, read the file or not. If we read the file without permission,
> we get an exception, if not, we can go to the next file without error.
>
> If that's unclear, please let me know, I'll try to give more informations
> or examples.
>
> Thank you.
>
> On 24 May 2016 at 10:19, Andrew Haley wrote:
>
> > On 05/20/2016 10:38 AM, Gilles Habran wrote:
> > > why is my message still waiting for approval after a month ?
> >
> > What is it you want Java to do? You can't walk the directory
> > because you don't have permission. sudo should work.
> >
> > Andrew.
> >
> >
>
