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New feature: Summaries tab

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I have been tasked to implement this new “Summaries” tab which is under “Assignments” and on the same level as “Groups”, “Submissions”, etc. It has a similar basic layout as the “Submissions” tab which is a table with functionalities such as filtering, pagination and sorting by columns. Each row in this table corresponds to a group; the columns are Repository, Commit date, Marking state, Grace credit used, Final grace, and grades for each marking criterion of the group. It serves as a detailed mark breakdown for each assignment.

While implementing it, I following the same logic for the “Submissions” tab for populating data, handling pagination and sorting. For the most part it works fine. However, I did come across two major roadblocks:

1. This is more of a difference to consider than a problem. Since I am displaying marks for each marking criterion, the number of columns is different across different assignments and it might change when the assignment rubric is changed. Therefore I need to dynamically display the criteria according to which assignment we are viewing. For the “Submissions” tab, since it only displays information that is common to every assignment, the number of columns won’t change.

2. Since now I have new columns, I need to implement new “compare” functions for them for the “sorting by column” to work. The way sorting and paginating works in the “Submissions” is as follows: The “compare” function for each column is coded in a constant hash in the Submission controller; when a pagination/sorting event occurs, the hash, along with other paratmeters, is passed to the handle_pagination_event helper function which handles sorting, and then pagination. The problem is I can’t store all the “compare” functions for the criteria in the same static fashion since the marking rubric may change and the corresponding compare functions required also change. In addition, since data in the criterion columns are of the same type (“mark”) and the implementation of the compare function should be identical except there is a unique mark id for each column.


The way I implemented it is that, hopefully following the “DIY” principle of Ruby on Rails, I created a single new compare function for comparing marks for a certain marking criterion. Instead of having two parameters (the two objects being compared), I have a third paramter, mark id,  for the compare function to get the desired mark. Then the two marks are extracted and compared according to the established logic. The whold picture is, the view generates table columns dynamically according to the rubric of the current assignment; when a “sort by criterion” event occurs, the corresponding mark id is passed along with other parameters and the hash which contains the new 3-parameter comapre function to the pagination helper function; the helper function executes the compare function to sort the data by this particular marking criterion.


While exploring other possible solutions, I have noticed that there are sortable table in Markus that are handled in a totally different way, namely the “FilterTable” javascript class. After reading the git wiki page of FilterTable, I found out that when the FilterTable object is created, the columns should be specified. Therefore it cannot handle situations where name and number of columns are changed dynamically. Moreover, it doesn’t seem to have pagination feature (it’s just a long table). I am by no means a javascript expert, so please correct me I am wrong.


The following are some screenshots of the Summaries tab:

(1) sorting by final grade as in the Submissions tab



(2) sorting by the first marking criterion:



(2) sorting by the second marking criterion:



Also I am relatively new to the Ruby on Rails world, so if you have any suggestions or better solutions, please let me know 🙂



Xiang Yu


Written by Xiang Yu

November 3rd, 2013 at 3:35 pm

Posted in Uncategorized

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