It might be useful to have the ability to read 1.2 format data files.
I committed this.
+1 I did not review DataFileReader12.java in detail. I looked at the rest of the patch closely and it looks good. Related tests pass.
Unless there are objections, I'll commit this soon.
A 1.2 format file, for tests.
Here's a new version of the patch that adds a static factory method, DataFileReader.openReader(), which looks at the file's version number and uses either the current implementation or the 1.2 implementation. The "tojson" tool and the MapReduce task are also updated to use this factory.
Here's the 1.2 file reader updated slightly so that it compiles in the current trunk.
This still needs tests. Perhaps we should add a small sample data file into subversion that we can read in a test?