log4j2 How to control logger name using %c{precision} OR logger{precision}

My logger names follow the convention: project.class

I want to ensure that, in logs, all prefixes except the last 2 are abbreviated to one letter each and the last 2 are printed in full. So I have full names for my loggers AND abbreviated names for other loggers E.g.:

• project.class is printed as project.class
• org.apache.spark.util.Utils is printed as o.a.s.util.Utils

According to documentation (as I interpret it) %c{1.2.*} is the right pattern for me.

But when I set pattern to:
%c %c{1} %c{2} %c{1.2.*} %c{1.3.*} %c{1.*.*} %c{2.*.*}%n

>>> l = spark.sparkContext._jvm.org.apache.log4j.LogManager.getLogger('project.class')
>>> o = spark.sparkContext._jvm.org.apache.log4j.LogManager.getLogger('org.apache.spark.util.Utils')
>>> l.info(''); o.info('')
project.class    class    project.class    p.class    p.class    p.class    pr.class
org.apache.spark.util.Utils    Utils    util.Utils    o.ap.spark.util.Utils    o.apa.spark.util.Utils    o.apache.spark.util.Utils    or.apache.spark.util.Utils
>>>

What I want is for it to print: project.class and o.a.s.util.Utils instead.

The description in official documentation seems VERY confusing:

> c{precision}
>
> logger{precision}
>
> Outputs the name of the logger that published the logging event. The logger conversion specifier can be optionally followed by precision specifier, which consists of a decimal integer, or a pattern starting with a decimal integer.
>
> When the precision specifier is an integer value, it reduces the size of the logger name. If the number is positive, the layout prints the corresponding number of rightmost logger name components. If negative, the layout removes the corresponding number of leftmost logger name components. If the precision contains periods then the number before the first period identifies the length to be printed from items that precede tokens in the rest of the pattern. If the number after the first period is followed by an asterisk it indicates how many of the rightmost tokens will be printed in full. See the table below for abbreviation examples.
>
> If the precision contains any non-integer characters, then the layout abbreviates the name based on the pattern. If the precision integer is less than one, the layout still prints the right-most token in full. By default, the layout prints the logger name in full.

The pattern you are looking for is %c{1.2*} introduced in version 2.20.0 (cf. LOG4J2-2785).

There are now four kinds of %c patterns:

• if the parameter is a positive integer n (e.g. %c{7}), only n rightmost components of the logger name are printed,
• if the parameter is a negative integer -n (e.g. %c{-7}), then the leftmost n components are dropped,
• if the parameter is of the form 1.n*, the n rightmost components are written in full, while the remaining ones are abbreviated to one letter,
• for any other pattern the numbers indicate how many letters to print from each component: e.g. 1.4~.7 means 1 letter from the first component followed by a dot . followed by 4 letters from the second component (followed by ~ if the name was abbreviated) and a dot .. The remaining components are abbreviated to 7 letters with a dot .. The last component is written down entirely.