= Neo4j Replay

Adds a replay behaviour to the Neo4j Node. This is under heavy development - don't use it yet.

== Usage

Simple Usage

class Person < Neo4j::Rails::Model

only object specifid with the replay method will replayable

replay
property :name
has_n :friends

end

p = Person.create(:name => 'andreas') p.name = 'foo' p.save Neo4j::Replay.version # => 1 Neo4j::Replay.rewind(0) p.reload! p.name => 'andreas'

Replay with relationships

p2 = Person.create p3 = Person.create p2.friends << p3 p2.save!

Neo4j::Replay.version # => 3 (3 transactions)

Neo4j::Replay.rewind(2) p2.reload! p3.reload! p2.friends.empty? #=> true

== Interaction with events

Raw interaction with Events

Neo4j::Replay.events #=> an array of events e.g. Neo4j::CreateNodeEvent

event = Neo4j::Replay::CreateNodeEvent.create(:replay_class => 'Person', :_replay_uuid => 1) event.replay # create a Person node event.rewind # deletes the Person node

event = Neo4j::Replay::DestroyNodeEvent.create(:replay_class => 'Person', :_replay_uuid => 1) event.replay # deletes the Person node, all the properties and relationship must already have been destroyed event.rewind # restore the Person node

event = Neo4j::Replay::DestroyRelEvent.create(:type => :friends, :_replay_uuid => 1, :_replay_uuid => 2) event.replay # creates relationship event.rewind # deletes relationship

only relationship between two node object using the ReplayMixin is allowed

event = Neo4j::Replay::CreateRelEvent.create(:type => :friends, :_replay_uuid => 1, :_replay_uuid => 2) event.replay # creates relationship event.rewind # deletes relationship

event = Neo4j::Replay::ChangePropEvent.create(:_replay_uuid => 1, :key => 'name', :new_value => 'andreas', :old_value => 'foo' ) event.replay # sets the property name to andreas event.rewind # restore the property to old value foo

== Custom UUID

Notice each node is expected to have a unique identifier :_replay_uuid, which will be generated. It is possible to user your own UUID:

class Person < Neo4j::Rails::Model property :emplyee_number index :emplyee_number replay :uuid => :employee_number end

== Persistance and serialization

Neo4j::Replay.export(from, to, filename) # stores the event in a csv file.

Neo4j::Replay.import(filename) # reads a csv file of events and replay them.