Class: Neo4j::Node

Inherits:
Object
  • Object
show all
Includes:
EntityEquality, Wrapper, PropertyContainer
Defined in:
lib/neo4j/node.rb

Overview

The base class for both the Embedded and Server Neo4j Node Notice this class is abstract and can't be instantiated

Direct Known Subclasses

Server::CypherNode

Defined Under Namespace

Modules: Wrapper

Constant Summary

Constant Summary

Constants included from PropertyValidator

PropertyValidator::VALID_PROPERTY_VALUE_CLASSES

Class Method Summary (collapse)

Instance Method Summary (collapse)

Methods included from PropertyContainer

#[], #[]=

Methods included from PropertyValidator

#valid_property?, #validate_property

Methods included from Wrapper

#neo4j_obj, #wrapper

Methods included from EntityEquality

#==

Constructor Details

- (Node) initialize



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# File 'lib/neo4j/node.rb', line 211

def initialize
  raise "Can't instantiate abstract class" if abstract_class?
  puts "Instantiated!"
end

Class Method Details

+ (Neo4j::Node) _load(neo_id, session = Neo4j::Session.current!)

Same as #load but does not try to return a wrapped node



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# File 'lib/neo4j/node.rb', line 195

def _load(neo_id, session = Neo4j::Session.current!)
  session.load_node(neo_id)
end

+ (Object) create(props = nil, *labels_or_db)

Creates a node



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# File 'lib/neo4j/node.rb', line 182

def create(props=nil, *labels_or_db)
  session = Neo4j::Core::ArgumentHelper.session(labels_or_db)
  session.create_node(props, labels_or_db)
end

+ (true, false) exist?(entity_or_entity_id, session = Neo4j::Session.current!)

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



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# File 'lib/neo4j/node.rb', line 201

def exist?(entity_or_entity_id, session = Neo4j::Session.current!)
  session.node_exist?(neo_id)
end

+ (Object) find_nodes(label, value = nil, session = Neo4j::Session.current!)

Find the node with given label and value



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# File 'lib/neo4j/node.rb', line 206

def find_nodes(label, value=nil, session = Neo4j::Session.current!)
  session.find_nodes(label, value)
end

+ (Object) load(neo_id, session = Neo4j::Session.current!)

Loads a node from the database with given id



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# File 'lib/neo4j/node.rb', line 188

def load(neo_id, session = Neo4j::Session.current!)
  node = _load(neo_id, session)
  node && node.wrapper
end

Instance Method Details

- (Object) _rel(spec = {})



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# File 'lib/neo4j/node.rb', line 155

def _rel(spec = {})
  raise 'not implemented'
end

- (Object) add_label(*labels)

Adds one or more Neo4j labels on the node



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# File 'lib/neo4j/node.rb', line 97

def add_label(*labels)
  raise 'not implemented'
end

- (Object) create_rel(type, other_node, props = nil)

Creates a relationship of given type to other_node with optionally properties



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# File 'lib/neo4j/node.rb', line 68

def create_rel(type, other_node, props = nil)
  raise 'not implemented'
end

- (Object) del

Deletes this node from the database



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# File 'lib/neo4j/node.rb', line 119

def del()
  raise 'not implemented'
end

- (Boolean) exist?



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# File 'lib/neo4j/node.rb', line 124

def exist?
  raise 'not implemented'
end

- (Object) get_property(key, value)

Directly get the property on the node (low level method, may need transaction)



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# File 'lib/neo4j/node.rb', line 60

def get_property(key, value)
  raise 'not implemented'
end

- (Object) labels



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# File 'lib/neo4j/node.rb', line 114

def labels()
  raise 'not implemented'
end

- (Object) node(specs = {})

Returns the only node of a given type and direction that is attached to this node, or nil. This is a convenience method that is used in the commonly occuring situation where a node has exactly zero or one relationships of a given type and direction to another node. Typically this invariant is maintained by the rest of the code: if at any time more than one such relationships exist, it is a fatal error that should generate an exception.

This method reflects that semantics and returns either:

  • nil if there are zero relationships of the given type and direction,

  • the relationship if there's exactly one, or

  • throws an exception in all other cases.

This method should be used only in situations with an invariant as described above. In those situations, a “state-checking” method (e.g. #rel?) is not required, because this method behaves correctly “out of the box.”



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# File 'lib/neo4j/node.rb', line 146

def node(specs = {})
  raise 'not implemented'
end

- (Enumerable<Neo4j::Node>) nodes(specs = {})

This method is abstract.
Note:

it's possible that the same node is returned more than once because of several relationship reaching to the same node, see #outgoing for alternative

Works like #rels method but instead returns the nodes. It does try to load a Ruby wrapper around each node



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# File 'lib/neo4j/node.rb', line 176

def nodes(specs = {})
  #rels(specs).map{|n| n.other_node(self)}
end

- (Hash<Symbol, Object>) props



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# File 'lib/neo4j/node.rb', line 24

def props()
  raise 'not implemented'
end

- (Object) props=(properties)

replace all properties with new properties



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# File 'lib/neo4j/node.rb', line 30

def props=(properties)
  raise 'not implemented'
end

- (Object) refresh

Refresh the properties by reading it from the database again next time an property value is requested.



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# File 'lib/neo4j/node.rb', line 35

def refresh
  raise 'not implemented'
end

- (Object) rel(spec = {})

Same as #node but returns the relationship. Notice it may raise an exception if there are more then one relationship matching.



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# File 'lib/neo4j/node.rb', line 151

def rel(spec = {})
  raise 'not implemented'
end

- (Boolean) rel?(spec = {})

Returns true or false if there is one or more relationships



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# File 'lib/neo4j/node.rb', line 161

def rel?(spec = {})
  raise 'not implemented'
end

- (Enumerable<Neo4j::Relationship>) rels(match = {dir: :both})

Returns an enumeration of relationships. It always returns relationships of depth one.

Examples:

Return both incoming and outgoing relationships of any type

node_a.rels

All outgoing or incoming relationship of type friends

node_a.rels(type: :friends)

All outgoing relationships between me and another node of type friends

node_a.rels(type: :friends, dir: :outgoing, between: node_b)

Options Hash (match):

  • :dir (Symbol)

    dir the direction of the relationship, allowed values: :both, :incoming, :outgoing.

  • :type (Symbol)

    the type of relationship to navigate

  • :between (Symbol)

    return all the relationships between this and given node



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# File 'lib/neo4j/node.rb', line 91

def rels(match = {dir: :both})
  raise 'not implemented'
end

- (Object) remove_label(*labels)

Removes given labels



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# File 'lib/neo4j/node.rb', line 108

def remove_label(*labels)
  raise 'not implemented'
end

- (Object) remove_property(key)

Directly remove the property on the node (low level method, may need transaction)



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# File 'lib/neo4j/node.rb', line 46

def remove_property(key)
  raise 'not implemented'
end

- (Object) set_label(*labels)

Sets label on the node. Any old labels will be removed



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# File 'lib/neo4j/node.rb', line 103

def set_label(*labels)
  raise 'not implemented'
end

- (Object) set_property(key, value)

Directly set the property on the node (low level method, may need transaction)



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

def set_property(key, value)
  raise 'not implemented'
end

- (Object) update_props(properties)

Updates the properties, keeps old properties



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# File 'lib/neo4j/node.rb', line 41

def update_props(properties)
  raise 'not implemented'
end