externalsort

external sorting for csv file with customized comparator and support to sort with encrypted file

Learning purpose

here is a project for you to learn how to do external sorting. the knowledge of it u can view here. https://15445.courses.cs.cmu.edu/fall2019/slides/10-sorting.pdf

You can clone this project, and read the code architecture. The Entrance class is ExternalSort.java; the core method is sortCsv(...);

To achieve this algorithm, there are two step.

first, you need split one large file to a lot of sorted small file which used this BatchSortedFileProducer.java
second, merge them with a lot of steps which used this SortedFilesMerger.java

Your task is to implement 3 methods in these two files. (search 'TODO' to easily find them)

After finished implementation, you can run the ExternalSortTest.java test cases to verify your program have bug or not.

There are a lot of paramter passed in the method you implement, read the comments and be careful with them.

If you want to find a library help do external sorting.

You could search 'ans.txt' in the project and use the code to fulfill TODO methods.