CSC/ECE 517 Spring 2020 - E2006. Refactor Tree Display Controller

E2006. Refactor tree_display_controller.rb

About Expertiza

Expertiza is a web application through which students can submit and peer-review learning objects (articles, code, web sites, etc). The Expertiza project is supported by the National Science Foundation.

Project Description

Problem Statement

E2006. Refactor tree_display_controller.rb

Background

The tree_display_controller is responsible for rendering hierarchical lists in the instructor user interface. Here is a sample instructor homepage:

You will see here that assignments are nested within courses. This means that the node for an assignment has a parent_id that points to a node for a course. Similarly, listings of questionnaires are hierarchical:

The various rubrics, as well as surveys, are types of questionnaires. So the parent_id of a particular rubric will be the type of rubric (e.g., teammate review) that it is.

The tree_display_controller is 379 lines long, and contains 45 methods. Many of those methods have similar names, yet there may be good reasons for having separate methods. Look over how these methods are used, and then decide. Then analyze the rest of the methods and try to find ways to save code and avoid DRY issues. Even if you cannot find a way to improve a method, you should be able to come up with a 1-line or 2-line comment explaining what that method does.

Issues

From the problem background, we have derived three main issues to focus on in the tree display controller:

• Remove unnecessary methods - Search the 45 methods defined in the controller to see where and why they are called. Remove outdated and unused methods, and see where it is fit to merge or replace methods.
• Save code and avoid DRY issues - In addition to removing unnecessary methods, code should be reduced wherever possible to make the controller smaller an easier to read.
• Improve understanding - For all necessary, complex methods in the controller, comments should be added to improve understanding of what methods do. This way, future reviewers won't have to search for implementations to understand the functionality when working on other issues.

Current Implementation

To be completed. (Repeat issues above and how they are currently being dealt with if they have a current solution).

Proposed Implementation

Collapse 'goto' methods

In the legacy code, 60 lines are dedicated to the 12 methods related to traversing the menu system. 11 of the methods call the goto_controller() method with different values, so we decided that those 11 methods could be condensed into single line methods with one overarching comment to describe them.

Original Implementation

  # refactored method to provide direct access to parameters
  def goto_controller(name_parameter)
    node_object = TreeFolder.find_by(name: name_parameter)
    session[:root] = FolderNode.find_by(node_object_id: node_object.id).id
    redirect_to controller: 'tree_display', action: 'list'
  end
 
  # direct access to questionnaires
  def goto_questionnaires
    goto_controller('Questionnaires')
  end
 
  # direct access to review rubrics
  def goto_review_rubrics
    goto_controller('Review')
  end
 
  # direct access to metareview rubrics
  def goto_metareview_rubrics
    goto_controller('Metareview')
  end
 
  # direct access to teammate review rubrics
  def goto_teammatereview_rubrics
    goto_controller('Teammate Review')
  end
 
  # direct access to author feedbacks
  def goto_author_feedbacks
    goto_controller('Author Feedback')
  end
 
  # direct access to global survey
  def goto_global_survey
    goto_controller('Global Survey')
  end
 
  # direct access to surveys
  def goto_surveys
    goto_controller('Assignment Survey')
  end
 
  # direct access to course surveys
  def goto_course_surveys
    goto_controller('Course Survey')
  end
 
  # direct access to courses
  def goto_courses
    goto_controller('Courses')
  end
 
  def goto_bookmarkrating_rubrics
    goto_controller('Bookmarkrating')
  end
 
  # direct access to assignments
  def goto_assignments
    goto_controller('Assignments')
  end

Proposed Implementation

  # The goto_ methods listed below are used to traverse the menu system. It is 
  # hard to tell exactly where they are called from, but at least some (if not all) 
  # are necessary. These functions may be better suited for another controller.
  def goto_controller(name_parameter)
    node_object = TreeFolder.find_by(name: name_parameter)
    session[:root] = FolderNode.find_by(node_object_id: node_object.id).id
    redirect_to controller: 'tree_display', action: 'list'
  end
 
  def goto_questionnaires; goto_controller('Questionnaires') end
  def goto_review_rubrics; goto_controller('Review') end
  def goto_metareview_rubrics; goto_controller('Metareview') end
  def goto_teammatereview_rubrics; goto_controller('Teammate Review') end
  def goto_author_feedbacks; goto_controller('Author Feedback') end
  def goto_global_survey; goto_controller('Global Survey') end
  def goto_surveys; goto_controller('Assignment Survey') end
  def goto_course_surveys; goto_controller('Course Survey') end
  def goto_courses; goto_controller('Courses') end
  def goto_bookmarkrating_rubrics; goto_controller('Bookmarkrating') end
  def goto_assignments; goto_controller('Assignments') end

Files modified

To be completed.

Test Plan

To be completed.

Code Coverage

To be completed.

Team Information

Brooks Anderson

Rick Holloway

PJ Loheide

Mentor: Dr. Edward Gehringer

References

To be completed.