Arangodb Java Driver and Graphs – Part 2

03Graphs, Java, Query LanguageTags: , , ,

After defining a graph and filling it with some vertices and edges (see part 1), the time has come to retrieve information out of the graph.

Please take a look at the defined graph operations of ArangoDB. These will be the base for our next examples. (Yes, there may be other ways to get the results, this post does not claim completeness!)

We will start with some easy stuff and then smoothly advance in complexity.

Question: “How many edges are defined within the graph?”

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A brief introduction to the Pregel module

00General, JavaTags:

This post is outdated, please see more recent infos below.

Please see a technical article about our current Pregel integration in our blog, details about the various Pregel algorithms ArangoDB supports in our documentation and a tutorial about Community Detection with real data in our training center.

 

 

Ever since Google introduced Pregel as a system for large-scale graph processing we thought of a way how to enable this feature in ArangoDB. So we set up an ArangoDB cluster, created some huge graphs and started evaluating the concept. We came up with a new ArangoDB module (called pregelRunner) that enables the user to write own algorithms, pass them to ArangoDB and have them executed in a Pregel-like fashion.

This means that the user’s algorithm is executed step wise on each server in the cluster in parallel for all its local vertices. In each step the vertices can send messages to each other to distribute information. These messages can be received by the other vertex in the next step. The algorithm terminates when there are no more active vertices left and no message has been sent.

We started to implement an experimental version of Pregel in ArangoDB. You need to check-out the pregel branch of ArangoDB in order to play with the following examples. Please be advised that the implementation is still in an early phase and very like to change. In this post we will provide a brief introduction to ArangoDB’s Pregel module by guiding you through the implementation of an example algorithm.

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Arangodb Java Driver and Graphs – Part 1

00Graphs, JavaTags: , , ,

With ArangoDB 2.2 the new graph API was released featuring multi collection graphs (see blog). With the new version (2.2.1) of arangodb-java-driver the new graph API is supported. In the following you can find a small example of creating a graph with Java.

For the import via maven and configuring the driver, please read the Basics and Driver Setup. For the following we assume, that arangodbDriver is a configured instance of the driver.

So let’s start the whole thing…

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How to use the ArangoDB Java Driver in batch and asynchronous mode?

00General, JavaTags: , ,

The current arangodb-java-driver supports the usage of ArangoDB’s batch and asynchronous interface. This post will guide you through the usage of these features.

The batch interface

The batch interface enables the user to stack a series of calls and execute them in a batch request. Each stacked request returns a request id that can be used to retrieve the single results from the batch response. So how do you use this feature in the java driver ?

First we create an instance of the java driver:

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The new ArangoDB Java Driver

00General, JavaTags: ,

A new arangodb-java-driver is out now, it’s on github. The driver is available for ArangoDB from version 2.2 onwards.

How to include the driver in your application ?

The driver is available as maven artifact. To add the driver to your project with maven, add the following code to your pom.xml:

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FullStack London

00Architecture, Conferences, Foxx, General, nodejsTags:

I recently had the chance to visit FullStack London, a well organized conference. Thanks a lot to Skills Matter. FullStack was opened by Douglas Crockford about “The Better Parts” of ES6. I cannot wait to start using them. Douglas was followed by Isaac Schlueter talking about open source in companies. Although this talk was not technical I learned a lot and it was very inspiring.

The remainder of the conference was all about using JavaScript mostly on server-side using Node.js or in robotics. As robotics is not my kind of topic I visited the talks about server-side JS. They confirmed my impression where JS development is heading to: Microservices. More info

How to Compile ArangoDB From Source

00C++, LinuxTags:

Though we provide a lot of pre-built packages for the stable versions of ArangoDB here, it is often more interesting to play with the bleeding edge development version. New ArangoDB features are normally added to the devel branch, where they can be tested, documented and improved. When a feature matures, it is either backported to a stable branch or will eventually be released when the next stable branch is forked from devel.

Contributing to the core of ArangoDB is also much easier with a ready-to-go devel version. This post explains how to set one up from scratch.

Read more on Jan’s Blog

Handling Binary Data in Foxx

00Foxx, JavascriptTags:

Handling binary data in JavaScript applications is a bit tricky because JavaScript does not provide a data type for binary data. This post explains how to use binary data in JavaScript actions written using ArangoDB’s Foxx.

String vs. binary data

Internally, JavaScript strings are sequences of 16 bit integer values. Furthermore, the ECMAScript standard requires that a JavaScript implementation should interpret characters in conformance with the Unicode standard, using either UCS-2 or UTF-16 encoding.

While this is fine for handling natural language, it becomes problematic when trying to work with arbitrary binary data. Binary data cannot be used safely in a JavaScript string because it may not be valid UTF-16 data.

Read more on Jan’s Blog

If you want to continue with other JavaScript related resources, you should start with ArangoDB NoSQL and JavaScript.