class Rangeable

File: rangeable.rb
(C): Hipposoft 2013
Purpose: Base class for objects which have a ‘used range’ defined by an oldest and newest item in the database.

26-Mar-2013 (ADH): Created.

Public Class Methods

used_range( accurate = false ) click to toggle source

Return a range of years used by all instances. Optionally pass ‘true’ if you want an actual Date object range rather than just a year range.

Derived classes must set USED_RANGE_COLUMN to the column for sorting; e.g. “created_at”. See also “appctrl_search_range_sql” and elsewhere.

# File app/models/rangeable.rb, line 21
def self.used_range( accurate = false )

  # May get nothing back from 'first' if there are no instances of the
  # record for this model at all in the database, so use 'try' to get
  # the 'created_at' value or, if there are no objects, 'nil'.

  first = self.unscoped.order( "#{ self::USED_RANGE_COLUMN } ASC"  ).first.try( :created_at )
  last  = self.unscoped.order( "#{ self::USED_RANGE_COLUMN } DESC" ).first.try( :created_at )

  first = last = Date.current if ( first.nil? ) # No instances of this object in database

  if accurate
    ( first.to_date )..( last.to_date )
  else
    ( first.year )..( last.year )
  end
end