Method createBTreeFile

creates a non random B+ tree file for testing @param columns - number of columns @param rows - number of rows @param columnSpecification - optional column specification @param tuples - optional list of tuples to return @param keyField - the index of the key field @return a BTreeFile @throws IOExcept

(int columns, int rows,
			Map<Integer, Integer> columnSpecification,
			ArrayList<ArrayList<Integer>> tuples, int keyField)