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

Prerequisites

Java
JRuby

Recommend way of installing JRuby

Install RVM: http://rvm.beginrescueend.com/
Install Jruby using rvm: rvm install jruby
Switch ruby to JRuby: rvm use jruby

Getting Started

install neo4jr-simple [http://gemcutter.org/gems/neo4jr-simple]
API Docs [http://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>

Contributors

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