Folks,
I checked and it's possible to use available() directly from stream
encapsulated at GridDataInput, but I'm not sure it's a good idea to update
almost obsolete classes.
Catching EOFException hack looks as reasonable solution in current case.
Thoughts?
чт, 31 мая 2018 г. в 11:39, Pavel Pereslegin <xxt...@gmail.com>:
> Hello Igniters!
>
> When deserializing Externalizable cache entry it's impossible to use
> ObjectInput#available method for checking is there anything left to
> read in buffer. This is because OptimizedObjectInputStream#available
> always returns -1 (hard-coded).
>
> Does anyone know the reasons why this method is not fully implemented?
> Is it acceptable to extend GridDataInput with method available() and
> implement it by calling available() from underlying input stream?
>
> I've faced with such problem when I tried to put additional field into
> GridCacheSetHeader class. It should be able to read both the old and
> new versions of this class, so, currently, I have to catch
> EOFException to safely read the old one.
>
> @Override public void readExternal(ObjectInput in) throws IOException {
> oldField = in.readInt();
> ...
> try {
> newField = in.readInt();
> }
> catch (EOFException e) {
> newField = DEFAULT_VALUE;
> }
> }
>
> With available() method this code will look like
>
> @Override public void readExternal(ObjectInput in) throws IOException {
> oldField = in.readInt();
> ...
> if (in.available() > 0)
> newField = in.readInt();
> else
> newField = DEFAULT_VALUE;
> }
>
> Which case is preferred – to catch EOFException or to implement
> available() at GridDataInput which looks obsolete?
>
