Peter Lawrey's Weblog

Fast simple configuration framework.

PeterLawrey — Sun, 16 Nov 2008 22:16:00 +0000

Essence JCF About a year ago, I considered having configuration files formatted as Java files instead of XML.
This approach has many benefits. The framework is small (15KB), supports pre-compilation, debugging, refactoring, code analysis, performance tuning and all the other tools support you get with regular Java files.
What the framework gives you is runtime compilation and loading. You can even compile and run a class in memory.

128-bit int and 128-bit double.

PeterLawrey — Mon, 15 Sep 2008 19:49:00 +0100

I put in an RFE which has been added to the bugs database.
Let me know what you think and ...

Low latency, high throughput Remote Method Invocation.

PeterLawrey — Sat, 09 Aug 2008 19:09:00 +0100

Being between jobs, I have a chance to do some open source.

I have written a simple, low latency, high ...

Generics, casting and warnings.

PeterLawrey — Tue, 13 May 2008 07:51:00 +0100

In this article I discuss
Generic as powerful compiler time check for typing rules for method parameters and return values. ...

arrays, Array and Arrays

PeterLawrey — Tue, 13 May 2008 07:49:00 +0100

In this article I discuss
Java is an OO language but it doesn't have a specific array type which is ...

Auto-boxing and assignment between primitives and wrappers

PeterLawrey — Tue, 13 May 2008 07:46:00 +0100

http://www.freshvanilla.org:8080/x/BIAp

The purpose of auto-boxing and un-boxing is to make assignment between primitives and their wrappers simpler. In most cases ...

Using foreach in Java 5 for control instead of waiting for Closures.

PeterLawrey — Sat, 26 Apr 2008 11:42:00 +0100

In this article I look at how you can use the foreach loop for control blocks

Zero footprint container, no libraries required. (Cont)

PeterLawrey — Sun, 20 Apr 2008 09:42:00 +0100

I have been a firm believer that Dependency Injection is a design principle, not a library you include.

java.lang.String which compresses itself.

PeterLawrey — Mon, 24 Mar 2008 12:04:00 +0000

In response to a similar article I discuss an approach having Strings auto-compress.

Looking for Good Reasons to have Closures in Java

PeterLawrey — Sat, 15 Mar 2008 15:51:00 +0000

In this article I go in search of good reasons to include closures in Java. The best reasons I could find were - Closures are cool. - Closures are familiar to those who use functional languages.

Looking for Good Reasons to have Closures in Java

PeterLawrey — Sat, 15 Mar 2008 12:52:00 +0000

In this article I go in search of good reasons to include closures in Java. The best reasons I could find were - Closures are cool. - Closures are familiar to those who use functional languages.

20 Advanced Java Interview Questions.

PeterLawrey — Fri, 14 Mar 2008 23:54:00 +0000

I started by giving simple, intermediate and advanced answers to the same questions.
http://www.freshvanilla.org:8080/display/www/Java+Interview+Questions

Essence Quant 0.2.0 Released - A Simple quantitative analysis library in Java.

PeterLawrey — Sun, 02 Mar 2008 14:16:00 +0000

Essence Quant 0.2.0 is a simple quantitative analysis library.
It supports options pricing and multi-threaded Monte Carlo simulations.
It also ...

Scripting Java in Java and debugging scripted code.

PeterLawrey — Tue, 04 Sep 2007 22:30:00 +0100

I recently tried the Java 6 compiler tools and after so head scratching I rather like the idea.
I got ...

Zero footprint container, no libraries required.

PeterLawrey — Tue, 04 Sep 2007 22:20:00 +0100

Recently, I was struck by the idea of having a IOC, DI container which does not require any libraires at ...

Endless iterators in Java, Hamming numbers and functional languages.

PeterLawrey — Mon, 03 Sep 2007 23:03:00 +0100

Inspired by an article on hamming numbers which shows a elegent solution in haskell, I thought I might try the same thing in Java ...

Its been a while since I blogged.

PeterLawrey — Mon, 09 Jul 2007 20:41:00 +0100

I have been busy at work. But I have also been on holiday to Queensland, moved house and we are about to go to Greece...
I have updated my linkin page. Any agents out there, check it out, send me a invitation. Any one else I suggest you set up a page.

FAQ: How does Essence Framework help manage Thread?

PeterLawrey — Fri, 02 Feb 2007 17:18:00 +0000

Components in Essence are bound to a thread pool. Single threaded components can be bound to a single thread pool, but can coexist with multi-threaded components. Typical applications designed this way use between 1 and 6 threads.

FAQ: Is Essence a clustering solution?

PeterLawrey — Fri, 02 Feb 2007 17:06:00 +0000

Clustering mean different things to different people. This solution allows you to cluster a collection such as Map, Queue, ConcurrentMap or JCache style Cache and anything it.

Essence 0.75 released and a new container planned for 1.0

PeterLawrey — Fri, 26 Jan 2007 23:09:00 +0000

It has a sample application Essence JMS 0.70 and an article on testing clustered components , some documentation and it has been added to SourceForge

Essence 0.75 has now been released http://sourceforge.net/projects/essence

Essence is an all in one library. Futher release will have a collection of small libraries to allow you to pick the bits you might want. The Essence release will be based on those and contain everything it has currently.

Testing failover of components in a cluster

PeterLawrey — Fri, 26 Jan 2007 22:51:00 +0000

This article explores an approach to testing a Component in a clustered environment. One unit test, tests nodes in the ...

Excellent presentation on Effective API Design

PeterLawrey — Sat, 13 Jan 2007 21:21:00 +0000

Effective API Design and the slides PDF presentations

Java Champion interviews.

PeterLawrey — Wed, 27 Dec 2006 10:43:00 +0000

I found these interview very interesting... Dr. Kabutz -- How to become a Java Expert (4:43); (JC alumni) Brian Goetz -- Java Concurrency (2:14); Rod Johnson -- Application of OSGi to the server side (5:58); Kirk Pepperdine -- Mr. Java Performance Tuning (12:27); Joe Walker -- new features of Reverse AJAX in DWR (18:07); Mike Cannon-Brookes -- Bamboo: Atlassian's new continuous intergration server (10:04); (JC alumni) Bruno Souza -- What's new with Netbeans (4:07). These are from https://java-champions.dev.java.net/

Java tip: ReentrantReadWriteLock and Lock upgrading.

PeterLawrey — Mon, 18 Dec 2006 10:49:00 +0000

Recently, to my surprise I discovered that ReentrantReadWriteLock not only didn't support lock upgrading but doesn't throw an exception nor even detect it as a deadlock. If a thread holds a read, the same thread cannot obtain a write lock. So I write utility which can help detect this condition.

Essence 0.67 has enhancements to its cluster support.

PeterLawrey — Sat, 16 Dec 2006 16:28:00 +0000

In Essence 0.67 has a number of enhancements over version 0.65 Download Essence
- Improved multi-threaded components and logical processes support.
- Improved data serialization for file storage and network transfers. As much as 5x smaller than standard serialization.
- Support for compressed network and file storage.
- Improved memory resource usage and cleanup. Thank you YourKit!
- Fisheye link added.

Scary use of generics

PeterLawrey — Tue, 05 Dec 2006 20:53:00 +0000

I have a method
    public static void include(Callback<Map<String, Map>> onCommit,
        Map<String, Map> changes,
        Callback<Map<String, Map>> onRollback) throws IllegalStateException {

Which updates a map
    private final Map<Callback, Pair<Callback, Map<String, Map>>> allChanges =
        new LinkedHashMap<Callback, Pair<Callback, Map<String, Map>>>();

I could have gone to four nested levels of generics but any more than three is a just scary IMHO.

Essence Framework 0.65 tested for 2-way durable mastering gets 68K updates/sec with 6.8 million lookup/sec

PeterLawrey — Sat, 02 Dec 2006 19:28:00 +0000

# High performance highly available clustering. Essence 0.65 has been tested with 2-way and 4-way mastering (were each update is committed to both or all 4 servers) and persisted to disk in near real time. On a Linux blade, the tests performed 68,000 updates per second and 6.8 million lookups per second concurrently in 2- way durable mastering mode. In 4-way durable mastering mode, the tests performed 31,000 updates per second and 3.1 million lookups per second. Performance test results

Essence 0.60 performs 50K updates/second with 4-way mastering

PeterLawrey — Sun, 26 Nov 2006 15:01:00 +0000

Now what it needs is good documentation. Suggestions, offers of help wanted. Good suggestions will be offered a reward via paypal.

Can paying for an IDE be justified?

PeterLawrey — Wed, 22 Nov 2006 21:25:00 +0000

A common question about IntelliJ is; why pay for it when Eclipse is free. I would argue there are many reasons to use IntelliJ and one is the quality of the code you produce. I recently ran my default code inspection setting against a reasonable mature project code base. This application is used for enterprise messaging and was developed under eclipse. Is an IDE which makes it easy to run programs which don't compile a good tool to produce quality code... You be the judge. http://www.jtoolkit.org/articles/inspect-code.html

SQL type FLOAT is a 64-bit but in Java is 32-bit

PeterLawrey — Wed, 22 Nov 2006 20:45:00 +0000

It is worth noting that in Java float/Float is 32-bit and has only 7 digits of precision at best. So basicly don't use them unless your eally need to.