The goal is to expand on our Word Count example in Cascading, using an ExpressionFunction to calculate TF-IDF. This shows how to use a SumBy and also a CoGroup to aggregate the data needed.
We'll keep building on this example to show features related to TDD and "local" mode.
More detailed background information and step-by-step documentation is provided at https://github.com/ConcurrentCore/impatient/wiki
To generate an IntelliJ project use:
To build the sample app from the command line use:
gradle clean jar
Before running this sample app, be sure to set your
HADOOP_HOME environment variable. Then clear the
output directory, then to run on a desktop/laptop with Apache Hadoop in standalone mode:
rm -rf output hadoop jar ./build/libs/impatient.jar data/rain.txt output/wc data/en.stop output/tfidf
To view the results:
An example of log captured from a successful build+run is at https://gist.github.com/3043791
For more discussion, see the cascading-user email forum.
Stay tuned for the next installments of our Cascading for the Impatient series.