Issue updating a FileDataModel

[Juan José Ramos]

I am having issues refreshing my recommender, in particular with the
DataModel.

I am using a FileDataModel and a GenericItemBasedRecommender that also has
a CachingItemSimilarity wrapping a FileItemSimilarity. But for the test I
am running I am making things even simpler.

By the time I instantiate the recommender, these two files are in the
FileSystem:
data/datamodel.txt
0,1,0.0

data/datamodel.0.txt
0,2,1.0

And then I run the code you can find below:

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  FileDataModel dataModel = new FileDataModel(new File("data/dataModel.txt"
));

   FileItemSimilarity itemSimilarity = new FileItemSimilarity(new File(
"data/similarities"));

 GenericItemBasedRecommender itemRecommender =
newGenericItemBasedRecommender(dataModel, itemSimilarity);

   System.out.println("Number of users in the system: " +
itemRecommender.getDataModel().getNumUsers()+" and " +
itemRecommender.getDataModel().getNumItems() + "items");

 FileWriter writer = new FileWriter(new File("data/dataModel.1.txt"));

 writer.write("1,2,1.0\r");

 writer.close();

   writer = new FileWriter(new File("data/dataModel.2.txt"));

 writer.write("2,2,1.0\r");

 writer.close();

   writer = new FileWriter(new File("data/dataModel.3.txt"));

 writer.write("3,2,1.0\r");

 writer.close();

   writer = new FileWriter(new File("data/dataModel.4.txt"));

 writer.write("4,2,1.0\r");

 writer.close();

   writer = new FileWriter(new File("data/dataModel.5.txt"));

 writer.write("5,2,1.0\r");

 writer.close();

   writer = new FileWriter(new File("data/dataModel.6.txt"));

 writer.write("6,2,1.0\r");

 writer.close();

 itemRecommender.refresh(null);

 System.out.println("Number of users in the system: " +
itemRecommender.getDataModel().getNumUsers()+" and " +
itemRecommender.getDataModel().getNumItems() + "items");

-----------------------------------------------------------------------------------------------------------------------

The output is the same in both println: Number of users in the system: 2
and 2items. So, only the information from the files that were on the system
by the time I run this test seem to get loaded on the DataModel.

What can be causing that? Is there a maximum number of updates a
FileDataModel can take up in every refresh?

Could it be that actually by the time I call itemRecommender.refresh(null)
the files have not been written to the FileSystem?

Should I be calling refresh in a different manner?

Thank you for your help.