RFR: 7113878: LogManager - namedLoggers should be ConcurrentHashMap instead of Hashtable

[Daniel Fuchs]

On 26/03/15 14:42, Jason Mehrens wrote:
> The snapshot enumeration is a welcomed change.  ConcurrentHashMap has legacy Hashtable methods so you can save a little bit by calling namedLoggers.keys() instead of wrapping the key set.

Yes - but the enumeration returned by ConcurrentHashMap.keys
is in fact an iterator which will let you remove keys.
I explicitly chose to use Collections.enumeration instead
to prevent providing unintended access.


best regards,

-- daniel

>
>
> Jason
>
> ----------------------------------------
>> Date: Thu, 26 Mar 2015 14:32:23 +0100
>> From: daniel.fuchs at oracle.com
>> To: david.holmes at oracle.com; core-libs-dev at openjdk.java.net
>> Subject: Re: RFR: 7113878: LogManager - namedLoggers should be ConcurrentHashMap instead of Hashtable
>>
>> On 26/03/15 13:28, David Holmes wrote:
>>> Hi Daniel,
>>>
>>> On 26/03/2015 10:08 PM, Daniel Fuchs wrote:
>>>> Please find below a trivial fix for
>>>>
>>>>
>>>> 7113878: LogManager - namedLoggers should be ConcurrentHashMap
>>>> instead of Hashtable
>>>
>>> As you say in the bug report, now that the map is always accessed within
>>> synchronized code this serves no purpose. The map not only doesn't need
>>> to be concurrent, it doesn't even need to be thread-safe! So why not
>>> replace with a simple HashMap?
>>
>> You found me out ;-) I should have mentioned it.
>> The enumeration of keys returned from the map will be iterated
>> outside of any synchronized block.
>> ConcurrentHashMap makes this safe.
>>
>> best regards,
>>
>> -- daniel
>>
>>
>>>
>>> David
>>>
>>>> https://bugs.openjdk.java.net/browse/JDK-7113878
>>>>
>>>> http://cr.openjdk.java.net/~dfuchs/webrev_7113878/webrev.00
>>>>
>>>> best regards,
>>>>
>>>> -- daniel
>>