This is a demo project that shows how to create a project using LensKit and set get the recommender running. It creates a simple command line application that builds a recommender from a delimited text file of ratings, then recommends items for users specified at the command line.
The main code is in org.grouplens.lenskit.hello.HelloLenskit. There are comments
so you can follow along and see what each stage of the process does.
If you are building a web application, you will need to adapt this project; the
project type will need to be changed to a war, and you won't want to use the
HelloLenskit main class. But the basic things done in that class will need to be
done in your application somewhere.
The LensKit home page has further documentation for LensKit, as well as links to our bug tracker and wiki. Also be sure to subscribe to our mailing list and ask any further questions you may have about using LensKit, and follow our Twitter account for updates on new releases and developments.
This project uses Apache Maven for build and dependency management. It is
easy to import into an IDE; a Maven plugin for Eclipse is available in the Eclipse
Marketplace (in your Help menu), and NetBeans and IntelliJ IDEA both have Maven
support built-in. These IDEs will import your project directly from the Maven pom.xml
and set up the build and dependencies.
Note: If you import the Mercurial repository into Eclipse using the MercurialEclipse plugin, you'll need to convert it to a Maven project (right-click the project, select Configure -> Convert to Maven Project) after importing.
The pom.xml file contains the project definition and its dependencies. Review this
for how we pull in LensKit, and how to depend on other modules.
In the Maven POM, we have set up the [AppAssembler plugin][] to produce a runnable
application with shell scripts and batch files to launch it. To build this, run the
package Maven target.
You'll also need a data set. You can get the MovieLens 100K data set here.
Once you have a data set, you can run lenskit-hello through your IDE, or from the command line (with Maven installed) as follows:
$ mvn package
$ /bin/sh target/hello/bin/lenskit-hello.sh ml100k/u.data <userid>
The default delimiter is the tab character.
Have fun!
Various people have ported the lenskit-hello project to other languages: