Class: Bulker::Pager

Inherits:
Object
  • Object
show all
Defined in:
lib/bulker/pager.rb

Overview

Bulker::Pager provides paging functionality to split large number of data to devided segments. It can handle large data very easily such like array with each method.

Bulker::Pager is especially designed for ActiveRecord.

class Item < ActiveRecord::Base; end
Bulker::Pager.each(Item.where(:status => "selling"), 100) do
  # do some process for each item
end

For other data source, Bulker::Criteria provides interface for Bulker::Pager.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(cursor, limit) ⇒ Pager

create pager from cursor data and limitaion limit

Raises:

  • (RangeError) 


23
24
25
26
27
 
# File 'lib/bulker/pager.rb', line 23

def initialize(cursor, limit)
  raise RangeError.new("limit must be positive number, but #{limit}") if limit <= 0
  @cursor = cursor
  @limit = limit
end

Class Method Details

.each(cursor, limit, &block) ⇒ Object

access to every cursor data with fetch limitation limit.



16
17
18
19
 
# File 'lib/bulker/pager.rb', line 16

def each(cursor, limit, &block)
  pager = Pager.new cursor, limit
  pager.each { |page| block.call(page) }
end

Instance Method Details

#each(&block) ⇒ Object

access to every data.



30
31
32
33
34
35
36
37
38
39
 
# File 'lib/bulker/pager.rb', line 30

def each(&block)
  size = @cursor.count
  pages = size / @limit + (size % @limit == 0 ? 0 : 1)
  pages.times do |i|
    offset = i * @limit
    @cursor.offset(offset).limit(@limit).each do |row|
      yield row
    end
  end
end