Class: Arrest::MemSource

Inherits:
Object
  • Object
show all
Defined in:
lib/arrest/transport/mem_source.rb

Constant Summary collapse

@@all_objects = 
{}
@@collections =

holds all objects of all types, each having a unique id

{}
@@edge_matrix =

For every has_many relation

{}
@@data =

matrix of edges based on node ids for has_many and belongs_to relations

{}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ MemSource

Returns a new instance of MemSource.



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# File 'lib/arrest/transport/mem_source.rb', line 44

def initialize
  @@all_objects = {} # holds all objects of all types,

  @@collections = {} # maps urls to collections of ids of objects
  @@random = Random.new(42)

  @@edge_matrix = {}
end

Instance Attribute Details

#data ⇒ Object

Returns the value of attribute data.



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# File 'lib/arrest/transport/mem_source.rb', line 7

def data
  @data
end

Instance Method Details

#cheat_collection(url, ids) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 290

def cheat_collection(url, ids)
    @@collections[url] = ids
end

#collection_json(values) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 158

def collection_json values
  single_jsons = values.map do |v|
    v.to_jhash.to_json
  end
  "[#{single_jsons.join(',')}]"
end

#collections ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 24

def collections
  @@collections
end

#delete(context, rest_resource) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 178

def delete(context, rest_resource)
  raise "To change an object it must have an id" unless rest_resource.respond_to?(:id) && rest_resource.id != nil
  @@all_objects.delete(rest_resource.id)
  @@collections.each_pair do |k,v|
    v.reject!{ |id| id == rest_resource.id }
  end
  remove_edges(@@edge_matrix, rest_resource.id)
  rest_resource
end

#delete_all(context, resource_path) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 147

def delete_all(context, resource_path)
  id_list = Array.new(@@collections[resource_path] || [])
  id_list.each do |base_id|
    @@collections.each_pair do |k,v|
      v.reject!{ |id| id == base_id }
    end
    @@all_objects[base_id].delete
    remove_edges(@@edge_matrix, base_id)
  end
end

#edge_count ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 36

def edge_count
  @@edge_matrix.values.inject(0){|sum, edges| sum + edges.length }
end

#edge_matrix ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 32

def edge_matrix
  @@edge_matrix
end

#get(context, sub, filters = {}) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 117

def get(context,sub, filters = {})
  Arrest::debug sub + (hash_to_query filters)
  # filters are ignored by mem impl so far

  id_list = parse_for_has_many_relations(sub)
  if id_list.empty?
    id_list = @@collections[sub] || []
  end

  objects = id_list.map do |id|
    @@all_objects[id]
  end

  wrap collection_json(objects), id_list.length
end

#get_many_other_ids(context, path) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 100

def get_many_other_ids(context,path)
  matcher = /^.+\/([^\/]+)\/([^\/]+)_ids$/.match(path)
  return [] unless matcher
  object_id = matcher[1]
  relation = matcher[2] + 's'
  if (object_id && relation && @@edge_matrix[object_id])
    id_list = []
    @@edge_matrix[object_id].each do |edge|
      if (edge.name.to_s == relation)
        id_list << edge.id
      end
    end
  end

  wrap id_list, id_list.length
end

#hash_to_query(filters) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 70

def hash_to_query filters
  ps = []
  filters.each_pair do |k,v|
    ps << "#{k}=v"
  end
  if ps.empty?
    ''
  else
    '?' + ps.join('&')
  end
end

#identify_and_store_edges(edge_matrix, rest_resource) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 218

def identify_and_store_edges(edge_matrix, rest_resource)
  from_id = rest_resource.id

  rest_resource.class.all_fields.each do |attr|
    if attr.is_a?(Arrest::HasManyAttribute)
      to_ids = rest_resource.send(attr.name) # -> foo_ids
      url_part = attr.url_part
      foreign_key = attr.foreign_key
      edge_matrix[from_id] ||= Set.new()
      if to_ids
        to_ids.each do |to_id|
          edge_matrix[from_id].add(Edge.new(foreign_key, url_part, to_id, true))
          edge_matrix[to_id] ||= Set.new()
          edge_matrix[to_id].add(Edge.new(foreign_key, url_part, from_id, false))
        end
      end
    elsif attr.is_a?(Arrest::BelongsToAttribute)
      to_id = rest_resource.send(attr.name)
      if to_id
        foreign_key = attr.foreign_key
        has_many_clazz = attr.target_class()
        hm_candidates = has_many_clazz.all_fields.find_all do |field|
          field.is_a?(Arrest::HasManyAttribute) && field.foreign_key.to_s == foreign_key
        end
        return if hm_candidates.empty?
        has_many_node = hm_candidates.first
        url_part = has_many_node.url_part

        edge_matrix[from_id] ||= Set.new()
        edge_matrix[from_id].add(Edge.new(foreign_key, url_part, to_id, true))
        edge_matrix[to_id] ||= Set.new()
        edge_matrix[to_id].add(Edge.new(foreign_key, url_part, from_id, false))
      end
    end
  end
end

#next_id ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 294

def next_id
  (0...32).map{ ('a'..'z').to_a[@@random.rand(26)] }.join
end

#node_count ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 40

def node_count
  @@edge_matrix.length
end

#objects ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 20

def objects
  @@all_objects
end

#parse_for_has_many_relations(resource_path) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 82

def parse_for_has_many_relations(resource_path)
  matcher = /^.+\/([^\/]+)\/([^\/]+)$/.match(resource_path)
  return [] unless matcher
  object_id = matcher[1]
  relation = matcher[2]

  if (object_id && relation && @@edge_matrix[object_id])
    result = []
    @@edge_matrix[object_id].each do |edge|
      if (edge.name.to_s == relation)
        result << edge.id
      end
    end
    return result
  end
  []
end

#post(context, rest_resource) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 270

def post(context, rest_resource)

  Arrest::debug "post -> #{rest_resource.class.name} #{rest_resource.to_hash} #{rest_resource.class.all_fields.map(&:name)}"
  raise "new object must have setter for id" unless rest_resource.respond_to?(:id=)
  raise "new object must not have id" if rest_resource.respond_to?(:id) && rest_resource.id != nil
  rest_resource.id = next_id
  @@all_objects[rest_resource.id] = rest_resource
  unless @@data[rest_resource.resource_path()] != nil
    @@data[rest_resource.resource_path()] = {}
  end
  Arrest::debug "child path #{rest_resource.resource_path()}"
  @@data[rest_resource.resource_path()][next_id.to_s] = rest_resource.id
  if @@collections[rest_resource.resource_path] == nil
    @@collections[rest_resource.resource_path] = []
  end
  @@collections[rest_resource.resource_path] << rest_resource.id

  true
end

#put(context, rest_resource) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 255

def put(context, rest_resource)
  raise "To change an object it must have an id" unless rest_resource.respond_to?(:id) && rest_resource.id != nil
  old = @@all_objects[rest_resource.id]

  remove_outgoing_edges(@@edge_matrix, old.id)

  rest_resource.class.all_fields.each do |f|
    old.send("#{f.name}=", rest_resource.send(f.name))
  end

  true
end

#remove_edges(edge_matrix, node_id) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 208

def remove_edges(edge_matrix, node_id)
  if (edge_matrix[node_id])
    edge_matrix[node_id].each do |edge|
      to_nodes = edge_matrix[edge.id]
      to_nodes.delete_if{|e| e.id == node_id}
    end
    edge_matrix.delete(node_id)
  end
end

#remove_outgoing_edges(edge_matrix, id) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 188

def remove_outgoing_edges(edge_matrix, id)
  if (edge_matrix[id])
    out_edges = edge_matrix[id].find_all{|edge| edge.tail}
    in_edges_to_delete = out_edges.map do |out_edge|
      foreign_edges = edge_matrix[out_edge.id] # the edge set of the foreign node that this node points to
      has_many_back_edges = foreign_edges.find_all do |for_edge|
        for_edge.id == id && for_edge.foreign_key == out_edge.foreign_key
      end
      [has_many_back_edges.first, out_edge.id] # first element may be nil
    end

    in_edges_to_delete.each do |tupel|
      if tupel[0]
        edge_matrix[tupel[1]].delete_if{|e| e.id == tupel[0].id && e.foreign_key == tupel[0].foreign_key}
      end
    end
    edge_matrix[id] = Set.new()
  end
end

#set_collection(clazz, scope, objects) ⇒ Object

only to stub collection for development



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# File 'lib/arrest/transport/mem_source.rb', line 56

def set_collection clazz, scope, objects
  url = clazz.scoped_path scope
  Arrest::debug "url:#{url}"
  @@data[url] = objects
end

#traverse(hash, keys) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 165

def traverse hash, keys
  if keys.empty?
    return hash
  end
  key = keys.first
  if hash == nil
    nil
  else
    traverse hash[key.to_s],keys.drop(1)
  end
end

#wrap(content, count) ⇒ Object 



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# File 'lib/arrest/transport/mem_source.rb', line 62

def wrap content,count
  "{
    \"queryTime\" : \"0.01866644\",
    \"resultCount\" : #{count},
    \"result\" : #{content} }"

end