Module: Neo4j::Wrapper::NodeMixin::ClassMethods

Defined in:
lib/neo4j-wrapper/node_mixin/class_methods.rb

Instance Method Summary collapse

Instance Method Details

#get_or_create(*args) ⇒ Object

Get the indexed entity, creating it (exactly once) if no indexed entity exist.

Examples:

Creating a Unique node


class MyNode
  include Neo4j::NodeMixin
  property :email, :index => :exact, :unique => true
end

node = MyNode.get_or_create(:email =>'[email protected]', :name => 'jimmy')

See Also:

  • #put_if_absent


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# File 'lib/neo4j-wrapper/node_mixin/class_methods.rb', line 64

def get_or_create(*args)
  props = args.first
  raise "Can't get or create entity since #{props.inspect} does not included unique key #{props[unique_factory_key]}'" unless props[unique_factory_key]
  index = index_for_type(_decl_props[unique_factory_key][:index])
  Neo4j::Core::Index::UniqueFactory.new(unique_factory_key, index) { |*| new(*args) }.get_or_create(unique_factory_key, props[unique_factory_key])
end

#load_entity(neo_id) ⇒ Object?

Note:

it will return nil if the node returned is not kind of this class

Loads a wrapped node from the database given a neo id.

Parameters:

  • neo_id (#to_i, nil)

Returns:

  • (Object, nil) —

    If the node does not exist it will return nil otherwise the loaded node or wrapped node.



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# File 'lib/neo4j-wrapper/node_mixin/class_methods.rb', line 87

def load_entity(neo_id)
  node = Neo4j::Node.load(neo_id)
  return nil if node.nil?
  return node if node.class == Neo4j::Node
  node.kind_of?(self) ? node : nil
end

#new(*args) ⇒ Object Also known as: create

Creates a new node or loads an already existing Neo4j node.

You can use two callback method to initialize the node init_on_load - this method is called when the node is loaded from the database init_on_create - called when the node is created, will be provided with the same argument as the new method

Does

  • sets the neo4j property ‘_classname’ to self.class.to_s

  • creates a neo4j node java object (in @_java_node)

If you want to provide your own initialize method you should instead implement the method init_on_create method.

Examples:

Create your own Ruby wrapper around a Neo4j::Node java object

class MyNode
  include Neo4j::NodeMixin
end

node = MyNode.new(:name => 'jimmy', :age => 23)

Using your own initialize method

class MyNode
  include Neo4j::NodeMixin

  def init_on_create(name, age)
     self[:name] = name
     self[:age] = age
  end
end

node = MyNode.new('jimmy', 23)

Parameters:

  • args —

    typically a hash of properties, but could be anything which will be handled in the super method

Returns:

  • the object return from the super method



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# File 'lib/neo4j-wrapper/node_mixin/class_methods.rb', line 40

def new(*args)
  node = Neo4j::Node.create
  wrapped_node = super()
  Neo4j::IdentityMap.add(node, wrapped_node)
  wrapped_node.init_on_load(node)
  wrapped_node.init_on_create(*args)
  wrapped_node
end

#unique_factory_key ⇒ Symbol?

Returns the property which has an unique index or nil.

Returns:

  • (Symbol, nil) —

    the property which has an unique index or nil



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# File 'lib/neo4j-wrapper/node_mixin/class_methods.rb', line 73

def unique_factory_key
  @unique_factory_key ||= begin
    unique = []
    _decl_props.each_pair { |k, v| unique << k if v[:unique] }
    return nil if unique.empty?
    raise "Only one property can be unique, got #{unique.join(', ')}" if unique.size > 1
    unique.first
  end
end