RFR: JDK-8189611: JarFile versioned stream and real name support

[Xueming Shen]

Hi Alan,

Here is the updated webrev with

(1) to move JarFile.getRealName into JarEntry
(2) to hide ZipFile.entryNameStream() from the public
(3) to reword the JarFile.versionedStream() to scope the "latest versined"

http://cr.openjdk.java.net/~sherman/8189611/webrev

thanks,
Sherman

On 11/20/17, 7:27 AM, Alan Bateman wrote:
> On 17/11/2017 16:53, Xueming Shen wrote:
>> :
>>>
>>> 3. Is ZipFile.entryNameStream really needed? Just asking because 
>>> zf.stream().map(ZipEntry::getName) is possible today.
>>>
>> It's not a "must" for sure. The motivation behind this is that my 
>> observation of most normal use scenario
>> inside JDK is that only the "name" info is interested/collect/used. 
>> The use pattern usually is
>>
>> zf.stream().map(ZipEntry::getName)
>>
>> same for the old Enumeration case, only the "name" is used and the 
>> "entry" object is thrown away mostly.
>>
>> Other than the memory consumption (showed in those two snapshots), 
>> it's also relatively costly to create
>> the ZipEntry especially its "esxdostime" calculation. The jmh numbers 
>> from a simple benchmark test
>> suggests the entryNameStream is about 15-20% faster. So, the only 
>> reason it's there is for better
>> performance.
> I can believe that it is faster but it does loose the ability to 
> filter (it requires checking for a trailing "/" to filter out 
> directories for example). I guess I don't object to adding this but it 
> feels like it an opportunity beyond JDK-8189611.
>
> -Alan