Class: PaginationHelper::Paginator

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
app/helpers/pagination_helper.rb

Overview

A class representing a paginator for an Active Record collection.

Defined Under Namespace

Classes: Page, Window

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(controller, item_count, items_per_page, current_page = 1, page_parameter = 'page') ⇒ Paginator

Creates a new Paginator on the given controller for a set of items of size item_count and having items_per_page items per page. Raises ArgumentError if items_per_page is out of bounds (i.e., less than or equal to zero). The page CGI parameter for links defaults to “page” and can be overridden with page_parameter.

Raises:

  • (ArgumentError)

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# File 'app/helpers/pagination_helper.rb', line 260

def initialize(controller, item_count, items_per_page, current_page=1,
               page_parameter='page')
  raise ArgumentError, 'must have at least one item per page' if
    items_per_page <= 0

  @controller = controller
  @item_count = item_count || 0
  @items_per_page = items_per_page
  @page_parameter = page_parameter

  self.current_page = current_page
end

Instance Attribute Details

#controllerObject (readonly)

Returns the value of attribute controller


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# File 'app/helpers/pagination_helper.rb', line 272

def controller
  @controller
end

#item_countObject (readonly)

Returns the value of attribute item_count


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# File 'app/helpers/pagination_helper.rb', line 272

def item_count
  @item_count
end

#items_per_pageObject (readonly)

Returns the value of attribute items_per_page


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# File 'app/helpers/pagination_helper.rb', line 272

def items_per_page
  @items_per_page
end

#page_parameterObject (readonly)

Returns the value of attribute page_parameter


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# File 'app/helpers/pagination_helper.rb', line 272

def page_parameter
  @page_parameter
end

Instance Method Details

#[](number) ⇒ Object

Returns a new Page representing the page with the given index number.


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# File 'app/helpers/pagination_helper.rb', line 318

def [](number)
  Page.new(self, number)
end

#basic_html(view, window_size = 2, link_to_current_page = false, params = {}) ⇒ Object

Creates a basic HTML link bar for the given view. The first and last pages of the paginator are always shown, along with window_size pages around the current page. By default, the current page is displayed, but not linked; to change this behavior, pass true to the link_to_current_page argument. Specify additional link_to parameters with params.


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# File 'app/helpers/pagination_helper.rb', line 335

def basic_html(view, window_size=2, link_to_current_page=false, params={})
  window_pages = current.window(window_size).pages
  return if window_pages.length <= 1 unless link_to_current_page
  
  html = ''
  unless window_pages[0].first?
    html << view.link_to(first.number, first.to_link(params))
    html << ' ... ' if window_pages[0].number - first.number > 1
    html << ' '
  end

  window_pages.each do |page|
    if current == page and not link_to_current_page
      html << page.number.to_s
    else
      html << view.link_to(page.number, page.to_link(params))
    end
    html << ' '
  end

  unless window_pages.last.last?
    html << ' ... ' if last.number - window_pages[-1].number > 1
    html << view.link_to(last.number, last.to_link(params))
  end
  
  html
end

#current_pageObject Also known as: current

Returns a Page object representing this paginator's current page.


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# File 'app/helpers/pagination_helper.rb', line 287

def current_page
  self[@current_page]
end

#current_page=(page) ⇒ Object

Sets the current page number of this paginator. If page is a Page object, its number attribute is used as the value; if the page does not belong to this Paginator, an ArgumentError is raised.


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# File 'app/helpers/pagination_helper.rb', line 277

def current_page=(page)
  if page.is_a? Page
    raise ArgumentError, 'Page/Paginator mismatch' unless
      page.paginator == self
  end
  page = page.to_i
  @current_page = has_page_number?(page) ? page : 1
end

#each(&block) ⇒ Object

Successively yields all the paginator's pages to the given block.


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# File 'app/helpers/pagination_helper.rb', line 323

def each(&block)
  page_count.times do |n|
    yield self[n+1]
  end
end

#first_pageObject Also known as: first

Returns a new Page representing the first page in this paginator.


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# File 'app/helpers/pagination_helper.rb', line 293

def first_page
  self[1]
end

#has_page_number?(number) ⇒ Boolean

Returns true if this paginator contains the page of index number.

Returns:

  • (Boolean)

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# File 'app/helpers/pagination_helper.rb', line 312

def has_page_number?(number)
  return false unless number.is_a? Fixnum
  number >= 1 and number <= page_count
end

#last_pageObject Also known as: last

Returns a new Page representing the last page in this paginator.


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# File 'app/helpers/pagination_helper.rb', line 299

def last_page
  self[page_count] 
end

#page_countObject Also known as: length

Returns the number of pages in this paginator.


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# File 'app/helpers/pagination_helper.rb', line 305

def page_count
  return 1 if @item_count.zero?
  (@item_count / @items_per_page.to_f).ceil
end