RFR: 8023168 - Cleanup LogManager class initialization and LogManager/LoggerContext relationship

[Daniel Fuchs]

Hi Mandy,

On 9/5/13 2:46 AM, Mandy Chung wrote:
>
> On 9/4/2013 12:56 PM, Daniel Fuchs wrote:
>> Hi,
>>
>> Please find below a changeset that will fix
>>
>> 8023168: Cleanup LogManager class initialization and
>>          LogManager/LoggerContext relationship.
>>
>> <http://cr.openjdk.java.net/~dfuchs/webrev_8023168/webrev.00/>
>>
>
> It is good to see the LogManager/Logger initialization untangled. This 
> helps in the long run.
>
> LogManager.java L342: thanks to adding the assert here. L340-341 can 
> be removed.
> This will be helpful in debugging (rather than swallowing the 
> exception).  The initialization has been so fragile and swallowing the 
> exception makes the problem even worse.  With this cleanup, I think 
> the initialization code will be more robust.
Will do.
>
> The ensureLogManagerInitialized method does the rest of the 
> initialization for the global log manager - it reads the 
> configuration, instantiates and registers the root logger, and also 
> register the global logger.  The comment L289-292 about deadlock 
> between two class initializers needs to be revise.
Will do.
>
> I agree with David that it's worth exploring if lazy holder class 
> idiom would help here - perhaps a holder class with a static 
> rootLogger field.
Well, I am not too keen on using a lazy holder class idiom here.
Though it is true that ensureLogManagerInitialized will do nothing if 
called before the 'manager' field
is set, or if called from additional instances of LogManager, I'd prefer 
not to stick this code in yet
another static initializer. If that's acceptable - I'd prefer to use a 
synchronized block within the
method and an additional volatile boolean to mark when initialization is 
finished.

This should make it possible to avoid entering the synchronized block 
once the LogManager
is initialized.

>
> Since you touch these lines, it's good to switch to try-with-resource.
>
> 1205         final InputStream in = new FileInputStream(fname);
> 1206         final BufferedInputStream bin = new BufferedInputStream(in);
> 1207         try {
> 1208             readConfiguration(bin);
> 1209         } finally {
> 1210             in.close();
> 1211         }
>
OK.

> Logger.java - getGlobal() method: would it help if the holder class
> has static Logger global field which is set during its class
> initialization.  It should guarantee that global.manager is set
> and the log manager initialization completes??

Can't do. Logger.global is a public final field.

-- daniel

>
> I was wondering if this can be simplified.
>
> thanks
> Mandy
>