add block handler to handle block files on different under file systems[Tachyon-33][SubTask 1]

details are on Tachyon's JIRA
BlockHandler is used to read and write block files on different under file systems, currently local file system is realized.
Thanks for the explanation.
On Aug 25, 2014 8:19 PM, "shimingfei" <notifications@github.com> wrote:

> In core/src/main/java/tachyon/client/BlockHandlerLocal.java:
>
> > +        LOCAL_FILE_CHANNEL.close();
> > +      } catch (IOException e) {
> > +        exception = e;
> > +      }
> > +    }
> > +    if (LOCAL_FILE != null) {
> > +      LOCAL_FILE.close();
> > +    }
> > +    if (exception != null) {
> > +      throw exception;
> > +    }
> > +  }
> > +
> > +  @Override
> > +  public boolean delete() throws IOException {
> > +    checkPermission();
>
> @dcapwell <https://github.com/dcapwell>
> there are two cases that needs check permission.
> 1. if there are more than one user, the block file is created by some
> user, and deleted by another user.
> 2. if block data is stored on persistence storage, and copied/backup to
> some new machine by other user, when deleting the added blocks on the new
> machines, permission needs to be checked.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/amplab/tachyon/pull/318/files#r16694008>.
>