Class: Thron::Paginator

Inherits:
Object
  • Object
show all
Defined in:
lib/thron/paginator.rb

Constant Summary collapse

MAX_LIMIT = 
50

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Paginator

Returns a new instance of Paginator.



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# File 'lib/thron/paginator.rb', line 16

def initialize(options = {})
  body = options[:body]
  limit = options.fetch(:limit) { MAX_LIMIT }
  fail ArgumentError, 'body must be a proc object' unless body.is_a?(Proc)
  fail ArgumentError, 'body must accept the limit and offset attributes' unless body.arity == 2
  @body = body
  @limit = self.class.check_limit(limit)
  @offset = offset.to_i
  @cache = {}
end

Instance Attribute Details

#cache ⇒ Object (readonly)

Returns the value of attribute cache.



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# File 'lib/thron/paginator.rb', line 14

def cache
  @cache
end

#limit ⇒ Object (readonly)

Returns the value of attribute limit.



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# File 'lib/thron/paginator.rb', line 14

def limit
  @limit
end

#offset ⇒ Object (readonly)

Returns the value of attribute offset.



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# File 'lib/thron/paginator.rb', line 14

def offset
  @offset
end

Class Method Details

.check_limit(limit) ⇒ Object 



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# File 'lib/thron/paginator.rb', line 8

def self.check_limit(limit)
  limit.to_i.tap do |limit|
    return MAX_LIMIT if limit > MAX_LIMIT
  end
end

Instance Method Details

#next ⇒ Object 



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# File 'lib/thron/paginator.rb', line 32

def next
  @offset = next_offset
  fetch.value
end

#preload(n) ⇒ Object 



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# File 'lib/thron/paginator.rb', line 37

def preload(n)
  starting_offset = max_offset
  (n).to_i.times do |i|
    index  = starting_offset.zero? ? i : (i + 1)
    offset = starting_offset + (index * @limit)
    fetch(offset)
  end
end

#prev ⇒ Object 



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# File 'lib/thron/paginator.rb', line 27

def prev
  @offset = prev_offset
  fetch.value
end

#total ⇒ Object 



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# File 'lib/thron/paginator.rb', line 46

def total
  return @total if @total
  return 0 if cache.empty?
  @total = cache.fetch(0).value.total
end