Auto detect Jansi

[charphi]

It would be usefull to make Ansi.AUTO detect if Jansi is available and enabled at runtime.
Thus, we wouldn't have to specify it manually.

For example:

AnsiConsole.systemInstall(); // Jansi magic
CommandLine.run(new WindowsJansiDemo(), args);
AnsiConsole.systemUninstall();

instead of

AnsiConsole.systemInstall(); // Jansi magic
CommandLine.run(new WindowsJansiDemo(), System.err, Ansi.ON, args);
AnsiConsole.systemUninstall();

[remkop]

Makes a lot of sense. I like this idea a lot.

What is a good way to detect that Jansi is installed? (I'm not sure that it is enough just to check that the Jansi jar is on the classpath...)

[charphi]

It seems that you just need to compare AnsiConsole.out and System.out such as:
AnsiConsole.out == System.out

Here is a quick example code:

static boolean isJansiEnabled() {
	try {
		Class<?> ansiConsole = Class.forName("org.fusesource.jansi.AnsiConsole");
		Field out = ansiConsole.getField("out");
		return out.get(null) == System.out;
	} catch (Exception ex) {
		return false;
	}
}

public static void main(String[] args) {
	System.out.println(isJansiEnabled());
	AnsiConsole.systemInstall();
	System.out.println(isJansiEnabled());
	AnsiConsole.systemUninstall();
	System.out.println(isJansiEnabled());
}

[remkop]

Perfect!

Do you feel like providing a PR for this?

[remkop]

#486 has been merged. Thanks for the contribution!