Module: Neo4j::Core::Node::ClassMethods

Included in:
Node
Defined in:
lib/neo4j-core/node/class_methods.rb

Instance Method Summary collapse

Instance Method Details

#_load(node_id, db = Neo4j.started_db) ⇒ Object

Same as load but does not return the node as a wrapped Ruby object.



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# File 'lib/neo4j-core/node/class_methods.rb', line 43

def _load(node_id, db = Neo4j.started_db)
  return nil if node_id.nil?
  db.graph.get_node_by_id(node_id.to_i)
rescue Java::OrgNeo4jGraphdb.NotFoundException
  nil
end

#exist?(entity_or_entity_id, db = Neo4j.started_db) ⇒ true, false

Checks if the given entity node or entity id (Neo4j::Node#neo_id) exists in the database.

Returns:

  • (true, false) —

    if exist



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# File 'lib/neo4j-core/node/class_methods.rb', line 53

def exist?(entity_or_entity_id, db = Neo4j.started_db)
  id = entity_or_entity_id.kind_of?(Fixnum) ? entity_or_entity_id : entity_or_entity_id.id
  node = _load(id, db)
  return false unless node
  node.has_property?('a')
  true
rescue java.lang.IllegalStateException
  nil # the node has been deleted
end

#load(node_id, db = Neo4j.started_db) ⇒ Object, ...

Loads a node or wrapped node given a native java node or an id. If there is a Ruby wrapper for the node then it will create and return a Ruby object that will wrap the java node.

Parameters:

  • node_id (nil, #to_i) —

    the neo4j node id

Returns:

  • (Object, Neo4j::Node, 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-core/node/class_methods.rb', line 69

def load(node_id, db = Neo4j.started_db)
  node = _load(node_id, db)
  node && node.wrapper
end

#new(*args) ⇒ Java::OrgNeo4jGraphdb::Node Also known as: create

Returns a new neo4j Node. The return node is actually an Java object of type Java::OrgNeo4jGraphdb::Node java object which has been extended (see the included mixins for Neo4j::Node).

The created node will have a unique id - Neo4j::Property#neo_id

Examples:

using default database


Neo4j::Transaction.run do
  Neo4j::Node.new
  Neo4j::Node.new :name => 'foo', :age => 100
end

using a different database


Neo4j::Node.new({:name => 'foo', :age => 100}, my_db)

Parameters:

  • args (Hash, Array) —

    either an hash of properties or an array where the first item is the database to be used and the second item is the properties

Returns:

  • (Java::OrgNeo4jGraphdb::Node) —

    the java node which implements the Neo4j::Node mixins



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# File 'lib/neo4j-core/node/class_methods.rb', line 25

def new(*args)
  # the first argument can be an hash of properties to set
  props = args[0].respond_to?(:each_pair) && args[0]

  # a db instance can be given, is the first argument if that was not a hash, or otherwise the second
  db = (!props && args[0]) || args[1] || Neo4j.started_db

  node = db.graph.create_node
  props.each_pair { |k, v| node[k]= v } if props
  node
end