Storm [1] and Spark [2] are two other distributed stream processing libraries in this family. Lots of good work being done in this area; batch-processing a la Hadoop is simply unnecessary for a lot of incredibly useful algorithms.<p>[1] <a href="https://github.com/nathanmarz/storm" rel="nofollow">https://github.com/nathanmarz/storm</a>
[2] <a href="http://www.spark-project.org/" rel="nofollow">http://www.spark-project.org/</a>