neo4jr-simple¶ ↑

A simple, ready to go JRuby wrapper for the Neo4j graph database engine which provides:

• The Neo4j Core Java Library (required and ready to use)

• Raw access to the Java API (using Neo4j::DB.instance )

• Extensions to the Java API to make node manipulation and traversal more rubyesque

• Working specs

• Loaded Neo4j sample database with IMDB data

• Nothing more then Neo4j goodness

• Java

• JRuby

1. Install RVM: rvm.beginrescueend.com/

2. Install Jruby using rvm: rvm install jruby

3. Switch ruby to JRuby: rvm use jruby

• {gem install neo4jr-simple} [gemcutter.org/gems/neo4jr-simple]

• {Neo4j API Docs} [api.neo4j.org/current/org/neo4j/api/core/package-summary.html]

• functional_example_spec includes examples of basic operations in neo4j like creating, retrieving and updating nodes along with simple traversal examples.

Basic Node creation:

Neo4jr::DB.execute do |neo|
  node = neo.createNode
  node[:name] = 'Deiters, Matt'
end

Retrieve a Node:

Neo4jr::DB.execute do |neo|
  node = neo.getNodeById(1234)
end

Find a Node by some value you control:

Neo4jr::DB.execute do |neo|
  # If you add a property 'identifier' to a node, the value can be used to retrieve the node by
  # This can by an id or string but the value must be unique to this node
  # e.g. node[:identifier] = user.id
  node = neo.find_node_by_identifier(user.id)
end

Traverse Database from a node:

Neo4jr::DB.execute do |neo|
  philip_seymour_hoffman = neo.getNodeById(1102)

  order         = Neo4jr::Order::BREADTH_FIRST
  stop_when     = Neo4jr::StopEvaluator::END_OF_GRAPH
  return_when   = Neo4jr::ReturnableEvaluator::ALL
  relationships = Neo4jr::RelationshipType.outgoing(:acted_in)

  traverser = philip_seymour_hoffman.traverse(order, stop_when, return_when, relationships)
  traverser.each do |node|
    #...
  end
end

Use command line shell to query and modify the graph:

neosh -path <path_to_neo_db>

https://github.com/mdeiters
https://github.com/klobuczek  
https://github.com/gregormelhorn

Copyright © 2009 Matthew Deiters. See LICENSE for details.