Questions on the NIO.2 API

[Rémi Forax]

  Le 31/01/2011 16:30, Martijn Verburg a écrit :
> Hi all,
>
> I've finally come back to this Chapter and am thinking about the 
> various rough code samples I've written (running b127 on Windows XP 
> SP3 32bit).  My next code sample simply takes the reader through some 
> of the file system api in order to explore some of the basics.
>
> import java.io.IOException;
> import java.nio.file.*;
>
> public class Listing_2_1
> {
>     public static void main(String[] args) throws IOException
>     {
>         try (FileSystem fileSystem = FileSystems.getDefault())
>         {
>             Path timeSheetFile 
> = fileSystem.getPath("C:/projects/timesheet.txt");
>             Path backupDir = fileSystem.getPath("H:/projects/");
>             Path backupFile 
> = fileSystem.getPath("H:/projects/timesheet.txt");
>
>             timeSheetFile.checkAccess(AccessMode.READ);
>             backupDir.checkAccess(AccessMode.WRITE);
>
>             FileStore backupFileStore = backupDir.getFileStore();
>             if (!backupFileStore.type().equals("NTFS"))
>             {
>                 throw new IOException("Suspicious storage type");
>             }
>
>             CopyOption copyOptions = StandardCopyOption.REPLACE_EXISTING;
>             timeSheetFile.copyTo(backupFile, copyOptions);
>         }
>     }
> }
>
> The code example is a pretty patsy one, but one gotcha in particular 
> was noticed by earlier reviewers.
>
> The FileStore object's type is simply a String as opposed to a 
> constant, enum or other defined type.  This makes it very hard to rely 
> on for decision making (as per the if statement I have above).  I 
> assume this is a limitation of being able to consistently detect the 
> underlying storage type?

Yes, the problem is that the string can be easily misspelled.
I wondering if it worth an API like this:

interface FileStoreType {
   public String getName();
}

public enum StandardFileStoreType implements FileStoreType {
   EXT3, EXT4, FAT32, NTFS;
   ...
}

public class FileStoreTypes {
   public static FileStoreType getFileStoreType(final String name) {
      // StandardFileStoreType.valueOf(name)
      // otherwise new FileStoreType() {
      //   public String getName() {
      //      return name;
      //   }
      //};
   }
}

In that case, the code can be rewrite to:
backupFileStore.type().equals(StandardFileStoreType.NTFS)) { ... }

>
> Thanks again all.
> Martijn
> (@java7developer - twitter)
>

Rémi