Class: Query::BaseQuery

Inherits:
Object
  • Object
show all
Includes:
Memery
Defined in:
app/services/query/base_query.rb

Overview

The purpose of this class is to provide common methods re-used in Query Objects.
Query object based on http://blog.codeclimate.com/blog/2012/10/17/7-ways-to-decompose-fat-activerecord-models/

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(relation, logger = nil) ⇒ BaseQuery

Returns a new instance of BaseQuery.



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# File 'app/services/query/base_query.rb', line 8

def initialize(relation, logger = nil)
  @relation = relation
  @logger = logger || Rails.logger
end

Instance Attribute Details

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# File 'app/services/query/base_query.rb', line 6

def logger
  @logger
end

#relation ⇒ Object (readonly)

Returns the value of attribute relation.



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# File 'app/services/query/base_query.rb', line 6

def relation
  @relation
end

Class Method Details

.median_record(relation) ⇒ Object

Class-level helper kept for callers that want to compute a median
against an arbitrary relation without instantiating a query object
(e.g. OpportunityQuery#median_opportunity_value uses it on a scoped
relation).

NOTE: previously memoized at the class level via Memery. That was
process-wide, never reset between requests, and keyed on the relation
object identity -- so distinct relations with identical SQL never hit
the cache, and identical relation instances reused across requests
returned stale records. Per-instance memoization above is enough
since query objects are short-lived per controller action.



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# File 'app/services/query/base_query.rb', line 51

def median_record(relation)
  record_count = relation.count
  record_count.positive? ? relation.offset((record_count / 2).floor).first : nil
end

Instance Method Details

#count ⇒ Object 



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# File 'app/services/query/base_query.rb', line 28

def count
  @relation.count
end

#find_each(&block) ⇒ Object 



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# File 'app/services/query/base_query.rb', line 23

def find_each(&block)
  @relation.
    find_each(&block)
end

#median_record ⇒ Object 



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# File 'app/services/query/base_query.rb', line 34

def median_record
  self.class.median_record(@relation)
end

#to_s ⇒ Object

to_s is only useful here when you work in console in these objects, because the basic to_s will
cause relations loaded in the initialize to trigger and that's not what we want unless we ask for it



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# File 'app/services/query/base_query.rb', line 15

def to_s
  "#{self.class.name} #{object_id}"
end

#to_sql ⇒ Object 



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# File 'app/services/query/base_query.rb', line 19

def to_sql
  @relation.to_sql
end