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From Ralph Goers <ralph.go...@dslextreme.com>
Subject Re: Getter method for retrieving the attributes of an appender from the LoggerContext
Date Wed, 27 Jan 2016 01:02:52 GMT
All the attributes have to have String representations to be usable in the XML, JSON &
Properties configurations. Yes, the Map could contain Objects but then every one of them has
to be cast to its real object to be usable. 

The map should be read-only because modifying its contents would have no effect on the appender.

The map should not be stored in an ivar but constructed whenever the attributes are retrieved.
Otherwise it will be temping to just keep them in a map and not as individual attributes,
which would cause problems.

If you have nesting such as  MyAppender extends MyBaseAppender extends AbstractOutputStreamAppender
extends AbstractAppender, I envision a fillAttributes method at each “level” that fills
in the attributes it knows about, so fillAttributeMap(map) should always call super.fillAttributeMap(map)
- except in AbstractAppender of course - and should call it before filling in its own attributes
so that it can override any values provided by the base Appenders.  If the primary Appender
does not implement fillAttributeMap then only the attributes of its super classes will be
included, which is actually correct for the SyslogAppender.

Ralph

> On Jan 26, 2016, at 5:24 PM, Apostolis Giannakidis <ap.giannakidis@gmail.com> wrote:
> 
> One thing to note here. Correct me if I am wrong, but the map should
> be Map<String,
> Object> because not all attributes are Strings. From the top of my head, I
> know that an attribute could also be a boolean.
> 
> On Wed, Jan 27, 2016 at 12:06 AM, Gary Gregory <garydgregory@gmail.com>
> wrote:
> 
>> I could see AbstractAppender implementing a getAttributes() method like
>> this:
>> 
>>    public Map<String, String> getAttributes() {
>>        Map<String, String> map = new HashMap<>();
>>        fillAttributeMap(map);
>>        // (1) should the map be read-only? why?
>>        // (2) if the map is cached in an ivar, the it must be updated by
>> each appender when an attribute changes, so
>>        // I'd say no and follow the KISS principle for now.
>>        return map;
>>    }
>> 
>>    protected void fillAttributeMap(Map<String, String> map) {
>>        // ...
>>    }
>> 
>> The boilerplate of creating and/or managing the map can be in
>> getAttributes().
>> Actually filling in the map in is done in fillAttributeMap() which each
>> appender can override.
>> 
>> fillAttributeMap() could be abstract to force each appender to make sure
>> developers pay attention to providing an implementation.
>> 
>> Gary
>> 
>> 
>> On Tue, Jan 26, 2016 at 3:46 PM, Apostolis Giannakidis <
>> ap.giannakidis@gmail.com> wrote:
>> 
>>> Well, since the idea is to add it to the Appender interface, it means
>> that
>>> all concrete Appenders need to be modified as well. So, yes, I can give
>> it
>>> a try to implement it for all the Appenders. One other simple way would
>> be
>>> to implement it once in the AbstractAppender so that all its subclasses
>>> will inherit it.
>>> 
>>> On Tue, Jan 26, 2016 at 9:15 PM, Gary Gregory <garydgregory@gmail.com>
>>> wrote:
>>> 
>>>> On Tue, Jan 26, 2016 at 1:06 PM, Apostolis Giannakidis <
>>>> ap.giannakidis@gmail.com> wrote:
>>>> 
>>>>> Actually, since this seems to be a useful feature, I would love to do
>>> the
>>>>> patch myself and contribute it to the project, if you don't mind.
>>>>> 
>>>> 
>>>> Do you plan on implementing this for all Appenders?
>>>> 
>>>> Gary
>>>> 
>>>>> 
>>>>> On Tue, Jan 26, 2016 at 8:56 PM, Ralph Goers <
>>> ralph.goers@dslextreme.com
>>>>> 
>>>>> wrote:
>>>>> 
>>>>>> Actually, I kind of like the idea of adding a getAttributes()
>> method
>>> to
>>>>>> the Appender interface. Then each concrete Appender would do:
>>>>>> 
>>>>>> public void getAttributes() {
>>>>>>    Map<String, String> attributes = new HashMap<>();
>>>>>>    super.getAttributes(attributes):
>>>>>>    attributes.put(“myAttribute1”, “value1”);
>>>>>>    return Collections.unmodifiableMap(attributes);
>>>>>> }
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>>> On Jan 26, 2016, at 1:28 PM, Gary Gregory <
>> garydgregory@gmail.com>
>>>>>> wrote:
>>>>>>> 
>>>>>>> How about adding getters for the fields
>>>>>>> in org.apache.logging.log4j.core.net.AbstractSocketManager?
>>>>>>> 
>>>>>>> Gary
>>>>>>> 
>>>>>>> On Tue, Jan 26, 2016 at 12:20 PM, Matt Sicker <boards@gmail.com>
>>>>> wrote:
>>>>>>> 
>>>>>>>> You could always use reflection to access it for now.
>>>>>>>> 
>>>>>>>> On 26 January 2016 at 14:17, Apostolis Giannakidis <
>>>>>>>> ap.giannakidis@gmail.com
>>>>>>>>> wrote:
>>>>>>>> 
>>>>>>>>> Thank you very much for the prompt reply Ralph.
>>>>>>>>> 
>>>>>>>>> As far as I can see, the SyslogAppender class does not
expose a
>>> way
>>>>> to
>>>>>>>>> access these attributes. So, if there is no other way
of
>>> accessing
>>>>>> these
>>>>>>>>> attributes, then I am not able to retrieve the attributes
that
>> I
>>>> want
>>>>>>>> from
>>>>>>>>> the existing SyslogAppender implementation. If I understand
>>>>> correctly,
>>>>>>>>> correct me if I am wrong, I might have to create my own
that
>>>> exposes
>>>>>>>> these
>>>>>>>>> attributes.
>>>>>>>>> 
>>>>>>>>> Apos
>>>>>>>>> 
>>>>>>>>> On Tue, Jan 26, 2016 at 8:03 PM, Ralph Goers <
>>>>>> ralph.goers@dslextreme.com
>>>>>>>>> 
>>>>>>>>> wrote:
>>>>>>>>> 
>>>>>>>>>> Not exactly. You can do:
>>>>>>>>>> 
>>>>>>>>>> Appender appender =
>>>>>>>> ctx.getConfiguration().getAppender(“syslogAppender”);
>>>>>>>>>> 
>>>>>>>>>> then you would have to do
>>>>>>>>>> 
>>>>>>>>>> SyslogAppender syslogAppender = (SyslogAppender)
appender;
>>>>>>>>>> 
>>>>>>>>>> normally you would probably use instanceof to verify
it is
>>>> actually
>>>>> a
>>>>>>>>>> SyslogAppender.
>>>>>>>>>> 
>>>>>>>>>> Once you have that you can call whatever methods
the
>>>> SyslogAppender
>>>>>>>>>> exposes for getting its attributes. They are not
stored in a
>> Map
>>>>>>>> however,
>>>>>>>>>> so you can’t just call a generic getAttribute method.
>>>>>>>>>> 
>>>>>>>>>> Ralph
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>>> On Jan 26, 2016, at 11:58 AM, Apostolis Giannakidis
<
>>>>>>>>>> ap.giannakidis@gmail.com> wrote:
>>>>>>>>>>> 
>>>>>>>>>>> Hello team,
>>>>>>>>>>> 
>>>>>>>>>>> I have created a logger with an appender using
the
>>>>>>>> ConfigurationBuilder
>>>>>>>>>> and
>>>>>>>>>>> the AppenderComponentBuilder.
>>>>>>>>>>> 
>>>>>>>>>>> Let's say that this is how I create my appender:
>>>>>>>>>>> 
>>>>>>>>>>> AppenderComponentBuilder appenderBuilder =
>>>>>>>>>>>              builder.newAppender( "syslogAppender",
>> "Syslog" )
>>>>>>>>>>>              .addAttribute( "protocol", "TCP"
)
>>>>>>>>>>>              .addAttribute( "host", "localhost"
)
>>>>>>>>>>>              .addAttribute( "port", 514 )
>>>>>>>>>>>              .addAttribute( "facility", "LOCAL2"
)
>>>>>>>>>>>              .addAttribute( "immediateFlush",
true )
>>>>>>>>>>>              .addAttribute( "newLine", true );
>>>>>>>>>>> 
>>>>>>>>>>> Then, after I finish creating the builder I use
the
>>>>>>>>>>> Configurator.initialize( builder.build() ) to
get the
>>>>> LoggerContext.
>>>>>>>>>>> 
>>>>>>>>>>> Is there any way I can access the attributes
of the appender
>>>>> through
>>>>>>>>> the
>>>>>>>>>>> LoggerContext?
>>>>>>>>>>> 
>>>>>>>>>>> For example something like this:
>>>>>>>>>>> 
>>>>>>>>>>> LoggerContext ctx = Configurator.initialize(
builder.build()
>> );
>>>>>>>>>>> 
>>>>>>>>>>> String hostname =
>>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>> 
>>>>>>>> 
>>>>>> 
>>>>> 
>>>> 
>>> 
>> ctx.getConfiguration()..getAppenders().get("syslogAppender").getAttribute("host");
>>>>>>>>>>> 
>>>>>>>>>>> Thank you all very much for your help.
>>>>>>>>>>> 
>>>>>>>>>>> Apostolis
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 
>>>>> ---------------------------------------------------------------------
>>>>>>>>>> To unsubscribe, e-mail:
>>> log4j-user-unsubscribe@logging.apache.org
>>>>>>>>>> For additional commands, e-mail:
>>>> log4j-user-help@logging.apache.org
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> 
>>>>>>>> --
>>>>>>>> Matt Sicker <boards@gmail.com>
>>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> --
>>>>>>> E-Mail: garydgregory@gmail.com | ggregory@apache.org
>>>>>>> Java Persistence with Hibernate, Second Edition
>>>>>>> <http://www.manning.com/bauer3/>
>>>>>>> JUnit in Action, Second Edition <
>> http://www.manning.com/tahchiev/>
>>>>>>> Spring Batch in Action <http://www.manning.com/templier/>
>>>>>>> Blog: http://garygregory.wordpress.com
>>>>>>> Home: http://garygregory.com/
>>>>>>> Tweet! http://twitter.com/GaryGregory
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>> ---------------------------------------------------------------------
>>>>>> To unsubscribe, e-mail: log4j-user-unsubscribe@logging.apache.org
>>>>>> For additional commands, e-mail:
>> log4j-user-help@logging.apache.org
>>>>>> 
>>>>>> 
>>>>> 
>>>> 
>>>> 
>>>> 
>>>> --
>>>> E-Mail: garydgregory@gmail.com | ggregory@apache.org
>>>> Java Persistence with Hibernate, Second Edition
>>>> <http://www.manning.com/bauer3/>
>>>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/>
>>>> Spring Batch in Action <http://www.manning.com/templier/>
>>>> Blog: http://garygregory.wordpress.com
>>>> Home: http://garygregory.com/
>>>> Tweet! http://twitter.com/GaryGregory
>>>> 
>>> 
>> 
>> 
>> 
>> --
>> E-Mail: garydgregory@gmail.com | ggregory@apache.org
>> Java Persistence with Hibernate, Second Edition
>> <http://www.manning.com/bauer3/>
>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/>
>> Spring Batch in Action <http://www.manning.com/templier/>
>> Blog: http://garygregory.wordpress.com
>> Home: http://garygregory.com/
>> Tweet! http://twitter.com/GaryGregory
>> 



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