Module: Liszt::ClassMethods

Defined in:
lib/liszt.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.extended(base) ⇒ Object 



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# File 'lib/liszt.rb', line 45

def self.extended(base)
  class << base
    attr_reader :liszt_sort_by, :liszt_append_new_items
  end
end

Instance Method Details

#clear_list(obj = {}) ⇒ Object 



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# File 'lib/liszt.rb', line 109

def clear_list(obj={})
  ordered_list(obj).clear
end

#initialize_list!(obj = {}, &block) ⇒ Object 



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# File 'lib/liszt.rb', line 51

def initialize_list!(obj={}, &block)
  objects = find(:all, :conditions => liszt_query(obj))

  # If the caller provided a block, or if they passed in a default
  # with the :sort_by option, sort the objects by that block's
  # output before populating the list with their ids. If not, put
  # the objects in descending order by id.
  ids = if block_given?
          objects.sort_by(&block).map(&:id)
        else
          if @liszt_sort_by
            objects.sort_by(&@liszt_sort_by).map(&:id)
          else
            objects.map(&:id).sort.reverse
          end
        end

  ordered_list(obj).clear_and_populate!(ids)
  ids
end

#liszt_key(obj = {}) ⇒ Object (private)

Return the key for the Redis list that includes the given object.



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# File 'lib/liszt.rb', line 119

def liszt_key(obj={})
  key = "liszt:#{table_name}"
  @liszt_scope.each do |scope|
    key << ":#{scope}:#{obj[scope]}"
  end
  key
end

#liszt_query(obj = {}) ⇒ Object (private)

Return the query that retrieves objects eligible to be in the list that includes the given object.



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# File 'lib/liszt.rb', line 129

def liszt_query(obj={})
  if @liszt_query.nil?
    query = ['1 = 1']

    @liszt_conditions.each do |key, value|
      query.first << " AND (#{table_name}.#{key} "
      if value.nil?
        query.first << "IS NULL)"
      else
        query.first << "= ?)"
        query << value
      end
    end

    @liszt_scope.each do |scope|
      query.first << " AND (#{table_name}.#{scope} = ?)"
    end

    @liszt_query = query
  end

  @liszt_query + @liszt_scope.map { |scope| obj[scope] }
end

#meets_list_conditions?(obj = {}) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/liszt.rb', line 113

def meets_list_conditions?(obj={})
  @liszt_conditions.all? { |key, value| obj[key] == value }
end

#ordered_list(obj = {}) ⇒ Object 



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# File 'lib/liszt.rb', line 72

def ordered_list(obj={})
  Liszt::RedisList.new(liszt_key(obj))
end

#ordered_list_ids(obj = {}) ⇒ Object 



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# File 'lib/liszt.rb', line 80

def ordered_list_ids(obj={})
  if ordered_list_initialized?(obj)
    ordered_list(obj).all
  else
    initialize_list!(obj)
  end
end

#ordered_list_initialized?(obj = {}) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/liszt.rb', line 76

def ordered_list_initialized?(obj={})
  ordered_list(obj).initialized?
end

#ordered_list_items(obj = {}, opts = {}) ⇒ Object 



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# File 'lib/liszt.rb', line 88

def ordered_list_items(obj={}, opts={})
  force_refresh = opts.delete(:force_refresh) || false
  was_initialized = ordered_list_initialized?(obj)
  ids = ordered_list_ids(obj)

  # If ordered_list_ids just did the initialization, we can trust that
  # the list of ids is accurate and ignore the force_refresh flag.
  if force_refresh and was_initialized
    objs = find(:all, {:conditions => liszt_query(obj)}.merge(opts))
    real_ids = objs.map(&:id)
    unlisted_ids = real_ids - ids
    if unlisted_ids.count > 0
      ids = ordered_list(obj).clear_and_populate!(unlisted_ids + ids)
    end
  else
    objs = find(:all, {:conditions => ['id in (?)', ids]}.merge(opts))
  end

  objs.sort_by { |obj| ids.index(obj.id) }
end