The application extracts the preferences (or signals) from the user navigation data to be used in the collaborative filtering algorithms implemented in Apache Mahout. The user navigation data is used to create a file with three columns: userID, itemID, value. Apache Mahout needs the first two fields to be provided as integers and the last as double in that same order. The IDs can be also provided as string but the recommender must be set up to handle the mapping between the string identifier and an integer identifier. The integer identifier can be created from the string ID using an hash function.
The parser can use different types of user feedbacks, also called signals or observations: views, downloads and comparisons. The views are events in which a user has seen the details of an item, usually after a search. A download refers to an event in which a user has downloaded a document related to an item and a comparison is the event in which a user has selected two or more items to make a comparison. A recommender based on Apache Mahout reads signals from a base file, e.g. signals.csv, and from other files in the same folder whose name begins in the same way as the base file, say signals-20180424.csv. The folders containing the users' log files are visited recursively. A filter can be used to parse only the files whose name start with a number of 8 digits that represents the date in which the file was created in the format yyyymmdd. When the filter is used only the file that starts with the same or higher number are parsed.

You need Java 8 and Maven to build the code.

The software can be downloaded from Github

$ git clone https://github.com/luigiselmi/mahoutdataproducer.git

From the project's root folder execute the command

$ mvn install

The parser can be run as an executable jar files. At least the path of a folder containing the files of one type of signals must be passed as an argument with the path to the output file.

$ java -jar target/mahoutdataproducer-0.1.0-SNAPSHOT-jar-with-dependencies.jar -output signals.csv  -downloads <downloads folder> -views <views folder> -comparisons <comparisons folder>

An optional numerical filter can be used to parse only the files that start with the same number or higher as in the example

$ java -jar target/mahoutdataproducer-0.1.0-SNAPSHOT-jar-with-dependencies.jar -filter 20180511 -output signals.csv  -downloads <downloads folder>