CSC/ECE 517 Spring 2015/oss E1503 RSA

E1503. Refactor Leaderboard model, Leaderboard_helper and LeaderboardController classes

This page provides a description of the Expertiza based OSS project. This project aimed at refactoring the Leaderboard model, LeaderboardController, and Leaderboard_helper classes as per standard coding methodology for Ruby on Rails.

Introduction to Expertiza

Expertiza is a peer review based system used to provide improved learning experience. Project is developed as a combined effort of students and faculty using the Ruby on Rails framework. Expertiza allows the instructor to create and customize assignments, create a list of topics the students can sign up for, have students work on teams and then review each other's assignments at the end. Expertiza supports submission of almost any document type, including the URLs and wiki pages.

Leaderboard is a module that can be used to find top three leaders in any class based on the score they have received on their submissions and reviews.

Project Description

Classes involved:

leaderboard.rb
leaderboard_controller.rb

Modules involved:

leaderboard_helper.rb

What they do

These class are responsible for calculating top 3 individuals which is to be displayed as the leaderboard for the class and generate a metric which aggregates peer review scores for all course assignments and then sorts individuals.

What needs to be done

Methods like getParticipantsScore and extractPersonalAchievements needs to be refactored as these single functions have multiple responsibilities. They can be modularized delegating single resposibility to single method. sortHash method is not an explicit leaderboard model and can be moved to helper methods. Some snippets of code are redundant and have no effect on functionality. They can be removed.

Changes Made<ref>https://github.com/rkyadav-ncsu/expertiza/commits/rails4</ref>

Leaderboard model was having public methods containing more than one feature in each method. We refactored such public methods in necessary public and private methods. Since we didn't create any new public method, we used the existing test cases to validate the changes. We removed helper methods from model class to respective helper class and changed all the references in model and controller classes.

Leaderboard Model

Method Name	Changes Made	Reason For Change
model/Leaderboard#getParticipantsScore	Refactored original method functionality into getAssignmentUniqueParticipantList, getAssignmentUniqueParticipantTeamList, getAggregatedAssignmentRevieweeList, getRevieweeListScore, and getUserScoreHashForCourse methods	Many different features were originally written in one method. We refactored this method into many methods to achieve singularity.
model/Leaderboard#sortHash helpers/leaderboard_helper#sortHash	Migrated method from Leaderboard model to leaderboard_helper class.	sortHash is a helper method and is not explicit part of model class, hence it was moved to achieve code reusability and remove redundancy.
model/Leaderboard scoreEntryScore parameter	Parameter name is changed to entryScore	The name was confusing. It was used to represent each entry's score, hence we changed the name to maintain readability of code.
model/Leaderboard#extractPersonalAchievements	Removed unwanted code snippets	Redundant code snippet was found which has no affect on program.
model/Leaderboard#extractPersonalAchievements	Refactored method functionality and created private method, getCourseAccomplishmentHash	More than one feature was implemented into one method. we split the functionality and remove code redundancy.

Leaderboard Controller

Method Name	Changes Made	Reason For Change
index	Updated reference to sortHash method	We moved sortHash method from model class to helper class. We updated all the old references for this method in index method on mentioned controller.

Re-factored Code Cases

Changes made to leaderboard_model.rb

Methods added to leaderboard_model.rb

  # This method returns the unique participants for assignment list.
  def self.getAssignmentUniqueParticipantList(assignmentList)
    AssignmentParticipant.where(:parent_id => assignmentList.pluck(:id)).uniq
  end

  # This method returns the unique participant teams for assignment list.
  def self.getAssignmentUniqueParticipantTeamList(assignmentList)
    Team.where("parent_id IN (?) AND type = ?", assignmentList.pluck(:id), 'AssignmentTeam').uniq
  end

Before Refactoring

# Get all participants of the assignment list
participantList = AssignmentParticipant.where(:parent_id => assignmentList.pluck(:id)).uniq

# Get all teams participated in the given assignment list.
teamList = Team.where("parent_id IN (?) AND type = ?", assignmentList.pluck(:id), 'AssignmentTeam').uniq
assignmentMap = getAssignmentMapping(assignmentList, participantList, teamList)

After Refactoring

assignmentMap = getAssignmentMapping(assignmentList, getAssignmentUniqueParticipantList(assignmentList), getAssignmentUniqueParticipantTeamList(assignmentList))

Private Methods added to leaderboard_model.rb

  #All the methods below are private methods
  private
  #End result is a hash (qType => (course => (user => score)))
  def Self.getUserScoreHashForCourse(scores,qTypeHash)
    for scoreEntry in scores
      revieweeUserIdList = Array.new
      if(assignmentMap["team"].has_key?(scoreEntry.reviewee_id))
        # Reviewee is a team. Actual Reviewee will be users of the team.
        teamUserIds = TeamsUser.where(:team_id => scoreEntry.reviewee_id).pluck(:user_id)
        revieweeUserIdList.concat(teamUserIds)
        courseId = assignmentMap["team"][scoreEntry.reviewee_id].try(:course_id).to_i
      else
        # Reviewee is an individual participant.
        revieweeUserIdList << assignmentMap["participant"][scoreEntry.reviewee_id]["self"].try(:user_id)
        courseId = assignmentMap["participant"][scoreEntry.reviewee_id]["assignment"].try(:course_id).to_i
      end

      questionnaireType = questionnaireResponseTypeHash[scoreEntry.object_type]

      addScoreToResultantHash(qTypeHash, questionnaireType, courseId, revieweeUserIdList, scoreEntry.score)
    end
    qTypeHash
  end

  def Self.getRevieweeListScore(revieweeList,questionnaireResponseTypeHash)
    ScoreCache.where("reviewee_id IN (?) and object_type IN (?)", revieweeList, questionnaireResponseTypeHash.keys)
  end
  # Aggregate total reviewee list for an assignment
  def Self.getAggregatedAssignmentRevieweeList(assignmentList)
    revieweeList=Array.new
    revieweeList= getAssignmentUniqueParticipantTeamList(assignmentList).pluck(:id)
    revieweeList.concat(getAssignmentUniqueParticipantTeamList(assignmentList).pluck(:id)).uniq!

  end
  # This method returns the unique participants for assignment list.
  def self.getAssignmentUniqueParticipantList(assignmentList)
    AssignmentParticipant.where(:parent_id => assignmentList.pluck(:id)).uniq
  end

  # This method returns the unique participant teams for assignment list.
  def self.getAssignmentUniqueParticipantTeamList(assignmentList)
    Team.where("parent_id IN (?) AND type = ?", assignmentList.pluck(:id), 'AssignmentTeam').uniq
  end
  #All the methods till here are private methods

New method added to leaderboard_helper.rb

  # This method does a destructive sort on the computed scores hash so
  # that it can be mined for personal achievement information
  def self.sortHash(qTypeHash)
    result = Hash.new
    # Deep-copy of Hash
    result = Marshal.load(Marshal.dump(qTypeHash))

    result.each { |qType, courseHash|
      courseHash.each { |courseId, userScoreHash|
        userScoreSortArray = userScoreHash.sort { |a, b| b[1][0] <=> a[1][0]}
        result[qType][courseId] = userScoreSortArray
      }
    }
    result
  end

Method removed from leaderboard_model.rb

  # This method does a destructive sort on the computed scores hash so
  # that it can be mined for personal achievement information
  def self.sortHash(qTypeHash)
    result = Hash.new
    # Deep-copy of Hash
    result = Marshal.load(Marshal.dump(qTypeHash))

    result.each { |qType, courseHash|
      courseHash.each { |courseId, userScoreHash|
        userScoreSortArray = userScoreHash.sort { |a, b| b[1][0] <=> a[1][0]}
        result[qType][courseId] = userScoreSortArray
      }
    }
    result
  end

Before Refactoring

  def self.addScoreToResultantHash(qTypeHash, questionnaireType, courseId, revieweeUserIdList, scoreEntryScore)

  userHash[revieweeUserId] = [scoreEntryScore, 1]

  qTypeHash[questionnaireType][courseId][revieweeUserId] = [scoreEntryScore, 1]

  currentUserScore[0] = (currentTotalScore + scoreEntryScore) / currentUserScore[1]

  csSortedHash = Leaderboard.sortHash(csHash)

After Refactoring

  def self.addScoreToResultantHash(qTypeHash, questionnaireType, courseId, revieweeUserIdList, entryScore)

  userHash[revieweeUserId] = [entryScore, 1]

  qTypeHash[questionnaireType][courseId][revieweeUserId] = [entryScore, 1]

  currentUserScore[0] = (currentTotalScore + entryScore) / currentUserScore[1]

  csSortedHash = LeaderboardHelper.sortHash(csHash)

Changes made to leaderboard_helper.rb

New method added to leaderboard_helper.rb

 # This method returns course accomplishment hash for a user
  def self.getCourseAccomplishmentHash(courseIdList,accomplishmentMap,userId,csHash)
    courseAccomplishmentHash = Hash.new
    csSortedHash = LeaderboardHelper.sortHash(csHash)

    for courseId in courseIdList
      for accomplishment in accomplishmentMap.keys
        # Get score for current questionnaireType/accomplishment, courseId and userId from csHash
        score = csHash.fetch(accomplishment, {}).fetch(courseId, {}).fetch(userId, nil)
        if(score)
          if courseAccomplishmentHash[courseId].nil?
            courseAccomplishmentHash[courseId] = Array.new
          end
          # Calculate rank of current user
          rank = 1 + csSortedHash[accomplishment][courseId].index([userId, score])
          total = csSortedHash[accomplishment][courseId].length

          courseAccomplishmentHash[courseId] << {:accomp => accomplishmentMap[accomplishment],
                                                 :score => score[0],
                                                 :rankStr => "#{rank} of #{total}"
          }
        end
      end
    end
    courseAccomplishmentHash
  end

Before Refactoring

    csSortedHash = LeaderboardHelper.sortHash(csHash)

    for courseId in courseIdList
      for accomplishment in accomplishmentMap.keys
        # Get score for current questionnaireType/accomplishment, courseId and userId from csHash
        score = csHash.fetch(accomplishment, {}).fetch(courseId, {}).fetch(userId, nil)
        if(score)
          if courseAccomplishmentHash[courseId].nil?
            courseAccomplishmentHash[courseId] = Array.new
          end
          # Calculate rank of current user
          rank = 1 + csSortedHash[accomplishment][courseId].index([userId, score])
          total = csSortedHash[accomplishment][courseId].length

          courseAccomplishmentHash[courseId] << {:accomp => accomplishmentMap[accomplishment],
                                                 :score => score[0],
                                                 :rankStr => "#{rank} of #{total}"
          }
        end
      end
    end
    courseAccomplishmentHash

After Refactoring

  return getCourseAccomplishmentHash(courseIdList,accomplishmentMap,userId,csHash)

Changes made to leaderboard_controller.rb

Before

@csHash = Leaderboard.sortHash(@csHash)

After

@csHash = LeaderboardHelper.sortHash(@csHash)

Automated Tests

Unit test

We didn't create any new public method as part of this project, instead we refactored the existing code. Existing test suit was suitable for testing our modifications.