Category Archives: Java

Nov 26 2012
19 Comments
Cypher, Java

Extending Neo4j

One of the great things about Neo4j is how easy it is to extend it. You can extend Neo4j with Plugins and Unmanaged Extensions. Two great examples of plugins are the Gremlin Plugin (which lets you use the Gremlin library with Neo4j) and the Spatial Plugin (which lets you perform spatial operations like searching for data within specified regions or within a specified distance of a point of interest).

Plugins are meant to extend the capabilities of the database, nodes, or relationships. Unmanaged extensions are meant to let you do anything you want. This great power comes with great responsibility, so be careful what you do here. David Montag cooked up an unmanaged extension template for us to use on github so lets give it a whirl. We are going to clone the project, compile it, download Neo4j, configure Neo4j to use the extension, test the extension and tweak it a bit.
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Jul 02 2012
6 Comments
Java

Batch Importer – Part 3

At the end of February, we took a look at Michael Hunger’s Batch Importer. It is a great tool to load millions of nodes and relationships into Neo4j quickly. The only thing it was missing was Indexing… I say was, because I just submitted a pull request to add this feature. Let’s go through how it was done so you get an idea of what the Neo4j Batch Import API looks like, and in the next blog post I’ll show you how to generate data to take advantage of it.
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Mar 13 2012
1 Comment
Gremlin, Java

JUNG in Neo4j – Part 1

It’s nice to have an arsenal. In the world of graph databases, one such stock room is the Java Universal Network/Graph Framework(JUNG) which contains a cache of algorithms from graph theory, data mining, and social network analysis, such as routines for clustering, decomposition, optimization, random graph generation, statistical analysis, and calculation of network distances, flows, and importance measures (centrality, PageRank, HITS, etc.).

We can use JUNG via the Blueprints ouplementation and access it via Gremlin. It doesn’t come pre-packaged with Neo4j, but Michael Hunger playing the role of “Tank” and was able to load up our stock room with a few key strokes.
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Feb 28 2012
32 Comments
Java

Batch Importer – Part 2

If you’ve been following along, we got Michael’s Batch Importer, compiled it, created some test data, ran it and saw millions of nodes and relationships loaded into Neo4j.

So now we’re ready for our own data. I am going to show you how to get data from a Relational Database like PostgreSQL into a format we can use. If you’re using SQL Server, MySQL, Oracle, etc, the directions will be slightly different, but you’ll get the picture.
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Feb 28 2012
46 Comments
Java

Batch Importer – Part 1

Data is everywhere… all around us, but sometimes the medium it is stored in can be a problem when analyzing it. Chances are you have a ton of data sitting around in a relational database in your current application… or you have begged, borrowed or scraped to get the data from somewhere and now you want to use Neo4j to find how this data is related.

Michael Hunger wrote a batch importer to load csv data quickly, but for some reason it hasn’t received a lot of love. We’re going to change that today and I’m going to walk you through getting your data out of tables and into nodes and edges.

Let’s clone the project and jump in.
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Feb 16 2012
5 Comments
Java

Importing Wikipedia into Neo4j with Graphipedia

Wouldn’t it be cool to import Wikipedia into Neo4j?

Mirko Nasato thought so, and built graphipedia using the batch importer that does just that.

It’s written in Java, so if you’re a pure ruby guy, I’ll walk you through the steps.

Let’s clone the project and jump in.

git clone git://github.com/mirkonasato/graphipedia.git
cd graphipedia

If you look in here you’ll see a pom.xml file which means you’ll need to download Maven and build the project.

sudo apt-get install maven2
mvn install

You’ll see a bunch of stuff flying by, that’s just the dependencies being downloaded. At the end you should see this:
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