Class: CohortScope::Cohort

Inherits:
Delegator
  • Object
show all
Defined in:
lib/cohort_scope/cohort.rb

Direct Known Subclasses

BigCohort, StrictCohort

Constant Summary collapse

IMPOSSIBLE_CONDITION = 
::Arel::Nodes::Equality.new(1,2)

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(obj) ⇒ Cohort

Returns a new instance of Cohort.



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# File 'lib/cohort_scope/cohort.rb', line 26

def initialize(obj)
  super
  @_ch_obj = obj
end

Class Method Details

.create(active_record, constraints, minimum_cohort_size) ⇒ Object

Recursively look for a scope that meets the constraints and is at least minimum_cohort_size.



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# File 'lib/cohort_scope/cohort.rb', line 7

def create(active_record, constraints, minimum_cohort_size)
  if constraints.none? # failing base case
    impossible_cohort = new(active_record.scoped.where(IMPOSSIBLE_CONDITION))
    impossible_cohort.impossible!
    return impossible_cohort
  end

  constrained_scope = active_record.scoped.where CohortScope.conditions_for(constraints)

  if constrained_scope.count >= minimum_cohort_size
    new constrained_scope
  else
    create active_record, reduce_constraints(active_record, constraints), minimum_cohort_size
  end
end

Instance Method Details

#+(other) ⇒ Object 



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# File 'lib/cohort_scope/cohort.rb', line 77

def +(other)
  case other
  when Cohort
    combined_conditions = (where_value_nodes + other.where_value_nodes).inject(nil) do |memo, node|
      if memo.nil?
        node
      else
        memo.or(node)
      end
    end
    Cohort.new active_record.where(combined_conditions)
  else
    super
  end
end

#__getobj__ ⇒ Object 



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# File 'lib/cohort_scope/cohort.rb', line 30

def __getobj__
  @_ch_obj
end

#__setobj__(obj) ⇒ Object 



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# File 'lib/cohort_scope/cohort.rb', line 33

def __setobj__(obj)
  @_ch_obj = obj
end

#active_record ⇒ Object 



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# File 'lib/cohort_scope/cohort.rb', line 73

def active_record
  __getobj__.klass
end

#any? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cohort_scope/cohort.rb', line 54

def any?
  return false if impossible?
  super
end

#as_json ⇒ Object 



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# File 'lib/cohort_scope/cohort.rb', line 42

def as_json(*)
  { :members => count }
end

#impossible! ⇒ Object 



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# File 'lib/cohort_scope/cohort.rb', line 46

def impossible!
  @impossible = true
end

#impossible? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cohort_scope/cohort.rb', line 50

def impossible?
  @impossible == true
end

#inspect ⇒ Object 



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# File 'lib/cohort_scope/cohort.rb', line 93

def inspect
  "#<#{self.class.name} with #{count} members>"
end

#none?(&blk) ⇒ Boolean

sabshere 2/1/11 ActiveRecord does this for #any? but not for #none?

Returns:

  • (Boolean) 


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# File 'lib/cohort_scope/cohort.rb', line 60

def none?(&blk)
  return true if impossible?
  if block_given?
    to_a.none? &blk
  else
    super
  end
end

#to_json ⇒ Object

sabshere 2/1/11 overriding as_json per usual doesn’t seem to work



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# File 'lib/cohort_scope/cohort.rb', line 38

def to_json(*)
  as_json.to_json
end

#where_value_nodes ⇒ Object 



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# File 'lib/cohort_scope/cohort.rb', line 69

def where_value_nodes
  __getobj__.instance_variable_get(:@where_values)
end