The locomotive driving Callisto is Eclipse 3.2, the latest version of the popular Eclipse tools framework and rich client platform."With Callisto, we can now align our product initiatives with one Eclipse release schedule" Eclipse 3.2 is significant on its own, containing a year's worth of enhancements to the Eclipse Platform, Java Development Tools, and Plug-in Development Environment. Of particular importance for Callisto are improvements to Eclipse's Update Manager, which drastically reduce download sizes (with Pack200 compression) and help pick the mirrors closest to you (through GeoIP).
Once you install Eclipse 3.2, bring up the Update Manager (Help > Software updates > Find and Install..., and navigate to the Callisto Discovery Site, the other projects that make up Callisto are displayed. Just pick and choose which functionality you're interested in, and only those parts will be downloaded and installed.
In the past one of the toughest things about using Eclipse plug-ins has been keeping all the dependencies straight. With Eclipse 3.2 and Callisto this is much easier. For example in the screen shot above I selected I wanted to do Web and J2EE Development. The Update Manager told me I needed version so-and-so of some other plug-in, so I just clicked the Select Required button and it figured out what to add. For anyone who has ever tried to install earlier versions of the Eclipse Web tools this will be a welcome improvement.
If successful, Callisto will likely set the model for eclipse.org project releases going forward. Already there is talk of a Europa release (based on Eclipse 3.3) next summer. Users and system integrators can look forward to the various projects releasing on independent schedules, with one big sync-up release a year. This predictability will be helpful for vendors building on top of the Eclipse Platform and other Eclipse projects, according to QNX's Doug Schaefer. He writes:
"Before the Callisto release, our QNX Momentics development platform had to juggle the separate release schedules of the Eclipse Platform and the CDT project. It was difficult to co-ordinate plug-ins targeting our QNX's Neutrino operating system and stay current with Eclipse releases. With Callisto, we can now align our product initiatives with one Eclipse release schedule, and have a common platform upon which to integrate partner plug-ins from vendors such as Klocwork and other Eclipse projects."
Other Eclipse members such as Borland, BEA, and Business Objects agree. You can read more comments from them about the Callisto Effect on the eclipse.org web site.
Callisto is not without its flaws. The different projects are not as integrated as they could be, and the install process could be improved. But some growing pains are only natural in such a large and diverse developer community. Callisto is the first attempt of putting it all together, and the lessons learned will be help improve future releases.