Two issues in Files

[Alan Bateman]

On 11/09/2013 22:36, Colin Decker wrote:
> Hi,
> I noticed a couple of small issues in Files for JDK8.
>
> The first, more significant issue, is that Files.readAllBytes(Path) 
> now creates a FileChannel, while FileSystemProvider implementations 
> are not required to support FileChannel. A SeekableByteChannel could 
> be created instead, and at least seems much more likely to be 
> supported than FileChannel.
I'll create a bug for this, it should be using newSeekableChannel and 
then testing if it is a FileChannel before deciding how to get the size.


>
> The second issue is with Files.write(Path, byte[], OpenOption...). 
> Instead of passing the whole input byte array to 
> OutputStream.write(byte[]), thus allowing the OutputStream 
> implementation to decide how best to handle it, it loops through 
> writing 8k slices of the array to the OutputStream. Is this intended? 
> It seems wasteful, particularly if an implementation (such as an 
> in-memory implementation) could just write the whole array at once 
> (and might even benefit from knowing up front the total number of 
> bytes being written.)
>
I don't know if there is a right answer to this one. If the underlying 
write requires using an intermediate buffer outside of the heap (common 
case for the default file system when the VM doesn't support any means 
to pin byte[] in the heap) then writing the entire array might be 
undesirable. So the slicing was intentional although there 8k might be a 
bit small.

-Alan.