Step 1: Install dependencies

$ gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
$ \curl -sSL https://get.rvm.io | bash -s stable
$ rvm install jruby
$ gem install pacer

Step 2: Start the IRB and load Pacer

$ irb
jruby-1.7.18 :001 > require 'pacer'
 => true

Step 3: Create a Graph

jruby-1.7.18 :002 > g = Pacer.tg()
 => #<PacerGraph tinkergraph[vertices:0 edges:0]

Windows users may want to try 

jirb_swing

Vertices

jruby-1.7.19 :003 > v1 = g.create_vertex()
 => #<V[0]>
jruby-1.7.19 :004 > v2 = g.create_vertex()
 => #<V[1]>

And edges

jruby-1.7.19 :005 > v1.add_edges_to(:likes, v2)
#<E[2]:0-likes-1>
Total: 1
 => #<Obj 1 ids -> lookup -> is_not(nil)>

jruby-1.7.18 :006 > v2.add_edges_to(:dislikes, v1)
#<E[3]:1-dislikes-0>
Total: 1
 => #<Obj 1 ids -> lookup -> is_not(nil)>

Let's make our data set a bit more interesting ...

All vertices

jruby-1.7.18 :013 > g.v
#<V[0]> #<V[1]> #<V[4]> #<V[5]> #<V[7]>
Total: 5
 => #<GraphV>

All edges

jruby-1.7.18 :014 > g.e
#<E[11]:5-posted-7>  #<E[12]:4-likes-7>  #<E[2]:0-likes-1>  ...
Total: 8
 => #<GraphE>

Specific element, by id

jruby-1.7.18 :015 > g.vertex(5)
jruby-1.7.18 :016 > g.edge(5)

First element of a route

jruby-1.7.18 :017 > g.v.first

Range of elements from a route

jruby-1.7.18 :018 > g.v[2..4]
# The statement above is equivalent to
jruby-1.7.18 :019 > g.v.offset(2).limit(3)

Edges with a given label

jruby-1.7.18 :021 > g.e(:likes)
#<E[12]:4-likes-7> #<E[2]:0-likes-1>
Total: 2
 => #<GraphE -> E-Property(:likes)>

jruby-1.7.18 :023 > bob.out_e
#<E[11]:5-posted-7>
Total: 1
 => #<outE>

jruby-1.7.18 :024 > bob.in_e
#<E[6]:4-follows-5>
Total: 1
 => #<inE>

jruby-1.7.18 :025 > bob.both_e
#<E[6]:4-follows-5> #<E[11]:5-posted-7>
Total: 2
 => #<bothE>

jruby-1.7.18 :027 > e.out_v
#<V[4]>
Total: 1
 => #<outV>

jruby-1.7.18 :028 > e.in_v
#<V[7]>
Total: 1
 => #<inV>

jruby-1.7.18 :029 > e.both_v
#<V[4]> #<V[7]>
Total: 2
 => #<bothV>

jruby-1.7.18 :030 > alice = g.v(name: 'Alice').first
 => #<V[4]>
jruby-1.7.18 :031 > alice.out_e
#<E[6]:4-follows-5> #<E[12]:4-likes-7>
Total: 2
 => #<outE>

jruby-1.7.18 :032 > g.v(type: 'person').out_e
#<E[6]:4-follows-5> #<E[12]:4-likes-7>  #<E[11]:5-posted-7>
Total: 3
 => #<GraphV -> V-Property(type=="person") -> outE>

 some_vertex.out_e.in_v

 some_vertex

 some_vertex.out_e

 some_vertex.in_e.out_v

 some_vertex

 some_vertex.in_e

All properties

jruby-1.7.18 :033 > g.v(type: 'person').first.properties
 => {"name"=>"Alice", "type"=>"person"}

jruby-1.7.18 :034 > g.v(type: 'person').properties
{"name"=>"Alice", "type"=>"person"}   {"name"=>"Bob", "type"=>"person"}
Total: 2
 => #<GraphV -> V-Property(type=="person") -> Hash-Map>

A specific property

jruby-1.7.18 :034 > g.v(type: 'person').first[:name]
 => "Alice"

jruby-1.7.18 :035 > g.v(type: 'person')[:name]
"Alice" "Bob"
Total: 2
 => #<GraphV -> V-Property(type=="person") -> Obj(name) -> decode>

Set the value of a property

jruby-1.7.18 :036 > alice = g.v(name: 'Alice').first
 => #<V[4]>
jruby-1.7.18 :037 > alice[:age] = 32
 => 32
jruby-1.7.18 :038 > alice.properties
 => {"name"=>"Alice", "type"=>"person", "age"=>32}

Delete property

jruby-1.7.18 :039 > alice[:age] = nil
 => nil
jruby-1.7.18 :040 > alice.properties
 => {"name"=>"Alice", "type"=>"person"}

Note: You can set/delete properties of a single item, not of a route.

Delete a single element

jruby-1.7.18 :041 > g.e.first.delete!
 => nil
jruby-1.7.18 :042 > g.v.first.delete!
 => nil

Delete all elements in a route

jruby-1.7.18 :043 > g.e.delete!
Bulk job -> 0!
 => 2

jruby-1.7.18 :044 > g.v.delete!
Bulk job ->!
Bulk job -> 0!
 => 4

jruby-1.7.18 :045 > g.v
Total: 0
 => #<GraphV>

Note: Deleting a vertex also deletes all of its edges.

People should be able to:

A simple social network

Types correspond to values of the type property 

Instances of these objects correspond to vertices