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Mustang: Find Disk Space With New File Methods

At 11:12 PM on Jul 12, 2005, R.J. Lorimer wrote:

Mustang is the codename for the next release of Java (Java 6, Java SE 6, JSE 6, whatever you want to call it), and is currently in early adoption ( Mustang.dev.java.net ). This effectively means that while it isn't released, you can start to play with the details in Mustang, and, within care and reason, start to consider them for your product that may be based on Java SE 6. I would recommend downloading a snapshot of Mustang, and trying your favorite Java applications on it, just to get a feel for what is coming. As most of you probably know, I am a glutton for punishment, and I'm never satisfied with the current state of affairs. So, instead, I have to download unfinished code, and extol the virtues of that which we as-of-yet don't have. Mustang is a veritable goldmine of unfinished 'latest-and-greatest' features. Now, this sounds silly, childish, and at least somewhat related to a mental disorder - but you know you all do it from time to time - and you know want to keep reading, and join me on this path of self indulgence.

One feature that developers have asked for again and again over the course of more than 8 years (697 votes is quite a few), yet Java has never had, is a facility for determining disk/partition size and availability. Up until now, there has been no way to determine the free/used space on a partition using Java. Mustang, however, now has preliminary support built in.

Here is a sample of how to use these methods (on Windows):

File f = new File("c:/");
// prints the volume size in bytes.
System.out.println(f.getTotalSpace());
// prints the total free bytes for the volume in bytes.
System.out.println(f.getFreeSpace());
// prints an accurate estimate of the total free (and available) bytes 
// on the volume. This method may return the same result as 'getFreeSpace()' on 
// some platforms.
System.out.println(f.getUsableSpace());	

From what I have seen, you should take care that the file object these methods are called on represents a partition or volume - otherwise the value returned could be 0. Also, be aware that these methods (although not very likely) have the potential to change - Mustang is not finished yet, and until it is, any new API is fair game to be changed, swapped, altered, poked, prodded, and set on fire. You have been warned - now go have fun with it.

Until next time,

R.J. Lorimer
Contributing Editor - rj -at- javalobby.org
Author              - http://www.coffee-bytes.com
Software Consultant - http://www.crosslogic.com