Blueprints Interface

Blueprints is an open source, community developed Java interface for graph databases. In many ways, Blueprints can be likened to the JDBC of the relational database community. Note that any technologies written to work with the Blueprints API can take advantage of a Blueprints-enabled graph database. Example technologies include the open-source products in the TinkerPop stack.

Introduction to TitanGraph

TitanGraph g = TitanFactory.open("/tmp/titan")
Vertex juno = g.addVertex(null);
juno.setProperty("name", "juno");
Vertex jupiter = g.addVertex(null);
jupiter.setProperty("name", "jupiter");
Edge married = g.addEdge(null, juno, jupiter, "married");

In the code example above, two vertices were created named “jupiter” and “juno.” These two vertices were joined in holy matrimony via a married edge. Please review the Blueprints Core API for a review of the Blueprints methods available.

Vertex Queries

Continuing with the example above, more vertices are created that are connected to by Juno.

Vertex turnus = g.addVertex(null);
turnus.setProperty("name", "turnus");
Vertex hercules = g.addVertex(null);
hercules.setProperty("name", "hercules")
Vertex dido = g.addVertex(null);
dido.setProperty("name", "dido");
Vertex troy = g.addVertex(null);
troy.setProperty("name", "troy");
Vertex jupiter = g.addVertex(null);
jupiter.setProperty("name", "jupiter");

Edge edge = g.addEdge(null, juno, turnus, "knows");
edge.setProperty("since",2010);
edge.setProperty("stars",5);
edge = g.addEdge(null, juno, hercules, "knows");
edge.setProperty("since",2011);
edge.setProperty("stars",1);
edge = g.addEdge(null, juno, dido, "knows");
edge.setProperty("since", 2011);
edge.setProperty("stars", 5);
g.addEdge(null, juno, troy, "likes").setProperty("stars",5);

Blueprints (and Titan) supports the notion of vertex-centric queries which can be understood as a query of the elements directly connected to a vertex (i.e. incident edges or adjacent vertices). An example vertex query is provided below:

Find all the people that Juno greatly admires who she has known since the year 2011.

Iterable<Vertex> results = juno.query().labels("knows").has("since",2011).has("stars",5).vertices()

The benefit of a vertex query is that it reduces the amount of data that needs to be pulled off the disk and filtered in-memory. This is important when considering extremely branchy graphs or graphs with “hot spots” called hubs or super-nodes. In these situations, it is imperative to reduce the search space to only that which is required for the particular query. Given the diagrammed graph above, if no restrictions are given to the query (e.g. juno.query().vertices()), then 5 vertices are returned.

for(Vertex vertex : juno.query().vertices()) { 
  System.out.println(vertex.getProperty("name")) 
}

// System.out
hercules
turnus
jupiter
dido
troy

However, given the query in the block of code above, only 1 vertex is returned — the Dido vertex. In this way, intelligent filtering provides performance benefits by reducing the processing and memory footprint required of the consuming application.

for(Vertex vertex : juno.query().labels("knows").has("since",2011).has("stars",5).vertices()) {
  System.out.println(vertex.getProperty("name"));
}

// System.out
dido