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Showing posts from May, 2011

This Blog Has Moved!

Right, so yes, five years ago I moved to github pages, and never bothered to redirect any of these pages there. Now I've moved on from there, and... Finally I am using my real domain, trishagee.com . My blog is now at trishagee.com/blog .  See you there!
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My first public appearance

I'm finally moving up from working behind the scenes to actually doing a (short) presentation for the LJC. I'm going to be giving a lightning talk on Wednesday at the AWS Elastic Beanstalk event , on the JCP - what it is and what our election to the executive committee means.   Ben and Martin's post  gives a little more background on the subject. Another LMAX LJC member  Mike will also be giving a lightning talk, on Project Coin. Now all I have to do is write it...
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Getting around a bit

I'm honoured to now be listed on three aggregated blog feeds: The new and somewhat embryonic blogs.lmax.com . The London Java Community Aggrity . ThoughtWorks Alumni , along with a whole host of distinguished names. The pressure's on to try and write useful stuff.  Oh OK, I'll settle for "entertaining".
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Why Java developers hate .NET

I have been struggling with .NET.  Actually, I have been fighting pitched battles with it. All I want to do is take our existing Java client example code and write an equivalent in C#.  Easy, right? Trisha's Guide to Converting Java to C# Turns out writing the actual C# is relatively straightforward.  Putting to one side the question of writing optimal code (these are very basic samples after all), to get the examples to compile and run was a simple process: 1. Find-and-replace the following (only you can't use Ctrl+R like I expect.  Sigh.) final = readonly (but remove from method params) System.out.printf = Console.WriteLine Map = Dictionary BigDecimal = decimal Set ... oh.  I have no idea. 2. When using callbacks, replace anonymous inner classes with delegates Java something.doSomething(new SomethingRequest(), new SomethingCallBack() { public void onSuccess() { System.out.println("Action successful"); } public voi...
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The London Java Community elected to the JCP SE/EE Executive Committee

As an associate member of the London Java Community (LJC), I'm very pleased with the news that we won an Open seat on the Java SE/EE executive committee.   The results show that we got an astonishing 47.5% of the vote - if an MP got voted in with that percentage the newspapers would probably be using the word "landslide". It's quite exciting to be one of the two user groups involved.  We hope to balance some of the larger corporate organisations, we're the voice of real life Java developers who use the language every day, for enterprise development or open source projects. You can argue Java is dying, but the community is not.  And I think we're exactly the people to guide its future. PS (Warning: gratuitous plug incoming) If you're at all Java-curious and you like drinking and attempting to be social, join us this Tuesday for our monthly Developer Sessions at the Porterhouse in Covent Garden.
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Popular posts from this blog

Dissecting the Disruptor: What's so special about a ring buffer?

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Recently we open sourced the LMAX Disruptor , the key to what makes our exchange so fast.  Why did we open source it?  Well, we've realised that conventional wisdom around high performance programming is... a bit wrong. We've come up with a better, faster way to share data between threads, and it would be selfish not to share it with the world.  Plus it makes us look dead clever. On the site you can download a technical article explaining what the Disruptor is and why it's so clever and fast.  I even get a writing credit on it, which is gratifying when all I really did is insert commas and re-phrase sentences I didn't understand. However I find the whole thing a bit much to digest all at once, so I'm going to explain it in smaller pieces, as suits my  NADD audience. First up - the ring buffer.  Initially I was under the impression the Disruptor was just the ring buffer.  But I've come to realise that while this data structure is at the hea...
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Dissecting the Disruptor: Writing to the ring buffer

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This is the missing piece in the end-to-end view of the Disruptor.  Brace yourselves, it's quite long.  But I decided to keep it in a single blog so you could have the context in one place. The important areas are: not wrapping the ring; informing the consumers; batching for producers; and how multiple producers work. ProducerBarriers The Disruptor code has interfaces and helper classes for the Consumer s, but there's no interface for your producer, the thing that writes to the ring buffer.  That's because nothing else needs to access your producer, only you need to know about it.  However, like the consuming side, a ProducerBarrier is created by the ring buffer and your producer will use this to write to it. Writing to the ring buffer involves a two-phase commit.  First, your producer has to claim the next slot on the buffer.  Then, when the producer has finished writing to the slot, it will call commit on the ProducerBarrier . So let's look at...
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Dissecting the Disruptor: How do I read from the ring buffer?

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The next in the series of understanding the Disruptor pattern developed at LMAX . After the last post we all understand ring buffers and how awesome they are.  Unfortunately for you, I have not said anything about how to actually populate them or read from them when you're using the Disruptor. ConsumerBarriers and Consumers I'm going to approach this slightly backwards, because it's probably easier to understand in the long run.  Assuming that some magic has populated it: how do you read something from the ring buffer? (OK, I'm starting to regret using Paint/ Gimp .  Although it's an excellent excuse to purchase a graphics tablet if I do continue down this road.  Also UML gurus are probably cursing my name right now.) Your Consumer is the thread that wants to get something off the buffer.  It has access to a ConsumerBarrier , which is created by the RingBuffer and interacts with it on behalf of the Consumer .  While the ring buffer obviously n...
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