MumbleCloseable goes backward

[Remi Forax]

On 06/27/2013 12:38 PM, Paul Sandoz wrote:
> On Jun 27, 2013, at 12:19 PM, Remi Forax <forax at univ-mlv.fr> wrote:
>
>> A Stream should be AutoClosable or MaybeCloseable, or MaybeMaybeNotCloseable ...
>> because using a TWR here goes in the wrong direction, the Stream API is fluent, from left to right and
>> the TWR is right to left because you have to declare a local variable and type it (again unlike the Stream API).
>>
>> So instead of:
>>   try (Stream<Path> stream = Files.walkFile(directory)) {
>>     stream.forEach(path -> {
>>        ...
>>     });
>>   }
>> which is an external way to manage the resources.
>>
>> Because we have lambda, we should promote the internal way to manage the resources, like the rest of the Stream API,
>> so walkFile should be written to take a Function<Stream, R>, like this:
>>   Files.walkFile(directory, stream -> stream.forEach(path -> {
>>     ...
>>   });
>> with the TWR written around the call to the function inside walkFile.
>>
>> so there is *no need* for a Mumble Closeable.
>>
> - R could be Stream.

yes, this has to be documented, but because the result value will be a 
closed Stream,
there is no issue, it will bark at first use.

>
> - ain't gonna work for flatMap:
>
>    Files.walk(dir, sp-> sp.flatMap(p -> Files.lines(p, Function.identity()))...);

you can return void/null, no ?

>
> - much harder to read than:
>
>    Files.walk(dir).flatMap(Files::lines)...

which leak resources.

>
> Paul.

Rémi