Small, fast, async, special, practical java logging.
- Console logging must provide information, not flood. When you run the application, you usually want to see its progress and results on-line. But in case of unexpected results, you also want to be able to analyse the application behaviour. So, you have two different purposes of logging. The Fastlog (by default) provides two outputs, yes, for different purposes: the console (STDOUT and STDERROR) and a file. The console is usually used just in time of running, to view the progress, so its log level is relatively high. Also it does not print unnecessary information such as time for each line for short processes (but if the process lasts more, it starts printing time). The log file is usually used for post process analisys and debugging, so its log level is low ("debug" by default), and it has time for each line. The application just prints to log, and the Fastlog itself knows whether to write to the file, to the console or both.
- Logging should not slow down the application. The Fastlog prints asynchronously, using the buffer with up to several hundreds log messages, in dedicated thread and tries to combine log lines to write several at once, so the output does not slow down the application (really it can if there are too many log lines to be printed to the console, which itself is not very fast, or the log file is on the slow drive)
- Console output should be colorized to distinguish errors and warnings. The Fastlog uses ANSI color for STDOUT and prints colorized messages not only on Linux, but even on Windows platform, in standard Windows console.
- Several parallel processes or threads or any other logical parts of the application should be distinguished in one log. It is very easy to assign prefixes to different logical parts of the application, and they are automatically added to each log line.
- An application running as a child of another application can use its own or parent logging (sharing the same log file in the latter case). Any number of loggers can be created, having or not parent loggers and sharing or not a log file, prefix, log levels (the logger object is very small and fast).
- A message text having the parameter placeholders can be distinguished from parameter values - as you wish.
- Logging has deferred output ability which can be used to log fast or slow runs differently. Imagine, you want the line "My process finished quickly and successfully" for fast run or "My process started" ... "My process finished, elapsed 1 hour" for slow. It is possible by logging "My process started" message, specifying, say, 5 seconds delay, and after the process finish, try to cancel the message and if successful, log "My process finished quickly and successfully" or if not successful log "My process finished, elapsed 1 hour" otherwise.
- When the message text parameters passed, they are automatically converted to strings, including objects INSIDE Maps, Arrays, Iterables, limiting the total message length and possible self-references.
See package.html for usage description and examples.