Point lambdafications in java.io

[Brian Goetz]

I did a quick look at the code, this would be very easy to implement by 
piggybacking on top of the existing checking for stream re-use.  Just as

   Stream s = ...
   s.forEach(...)
   s.forEach(...) // throws ISE

fails because the stream is being "reused", we can have future stream 
operations fail with ISE if they are initiated after the stream is 
closed.  For the example behavior you suggest, probably anything could 
happen.  But we can make a good-faith effort to prevent future stream 
operations from proceeding (which, Mike noted, is more than a lot of the 
existing Autocloseable IO classes do.)

On 6/18/2013 12:30 PM, Sam Pullara wrote:
> I am very much in favor of a way to signal to the stream to relinquish resources so that you don't have to exhaust it to ensure that it is cleaned up. That said, without things like takeWhile() I'm not sure that there are many cases where you can close the stream unless you are in an exception state. What would be the semantics of something like this:
>
> Stream stream = list.stream();
> stream.forEach(o -> stream.close());
>
> Sam
>
> On Jun 18, 2013, at 9:05 AM, Brian Goetz <brian.goetz at oracle.com> wrote:
>
>> The libraries team added the following methods to java.io and java.nio, with discussion on corelibs-dev:
>>
>> In java.io.BufferedReader:
>>   Stream<String> lines()
>>
>> In java.nio.Files, static methods for:
>>
>>   CloseableStream<Path> list(Path dir) throws IOException;
>>
>>   CloseableStream<Path> walk(Path start, int maxDepth, FileVisitOption... options) throws IOException
>>
>>   CloseableStream<Path> walk(Path start, FileVisitOption... options) throws IOException
>>
>>   CloseableStream<Path> find(Path start,
>>                            int maxDepth,
>>                            BiPredicate<Path, BasicFileAttributes> matcher,
>>                            FileVisitOption... options)
>>         throws IOException
>>
>>   CloseableStream<String> lines(Path path, Charset cs) throws IOException
>>
>>
>> CloseableStream simply extends Stream and AutoCloseable, making it suitable for use with try-with-resources:
>>
>> public interface CloseableStream<T> extends Stream<T>, AutoCloseable {
>>     void close();
>> }
>>
>> Should we consider moving AutoCloseable up to Stream and friends, and get rid of CloseableStream?
>>
>