joomla/joomla-platform — pull request #1587 by okonomiyaki3000 (2012-10-09 09:52:19+00:00)
Title: Loggers can be added which exclude specific categories

Also, unit test for adding loggers to exclude specific categories

Suppose you want to separate your logs by category. Until now, it was only possible if you knew the names of all possible categories (which you don't). So now, let's say you want your deprecation logs in one place, your query logs in another, and all others someplace else. Then you just need to do this:

```php
// Normal log files
JLog::addLogger(array('text_file' => 'deprecated'), JLog::ALL, 'deprecated');
JLog::addLogger(array('text_file' => 'databasequery'), JLog::ALL, 'databasequery');
// Excluding categories
JLog::addLogger(array('text_file' => 'others'), JLog::ALL, array('deprecated', 'databasequery'), true);
```