AutoList Design Pattern

Description: The AutoList design pattern is used when a list of all instances of a class is desired. If a class inherits from AutoList, all instances of that class are inserted to the list as they are created, and are removed when they are destroyed.

Eclipse + OSGI
This is a pretty interesting pattern because it essentially creates a dynamic list objects that are of a certain type (or interface to be exact). This concept is prevalent throughout many other patterns like location services and Eclipse Extension Points. The Eclipse extension point when mixed with OSGI Dynamic loading and unloading is basically the AutoList pattern done in a declarative way. When you provide an extension in Eclipse and your extension implements an interface your newly created object is now part of the Extension registry (somewhat). This means the plugin that has instantiated your object has added it to its list of objects. Mix this with the Extension Registry listener concepts and your plugin can now remove that object from its list when the parent plugin gets unloaded.

So in short, this is a great pattern and can easily be implemented in Java using technologies like OSGI bundles and Eclipse Extensions.

Java 5 Generics
However, how do you do this with basic Java? It is not like you can have multiple inheritance! But wait, Java 5 has the concept of Generics which are implemented as Interfaces. So could you actually write the AutoList pattern using the basic Java language? Almost, you would have to have your implementers write all of the code to properly implement the pattern (much uglier than C++).

Aspect Oriented Programming
Lastly, one thing I thought of was the use of Aspect Oriented Programming (AspectJ) to accomplish this on existing objects that declare similar methods and behavior. Your aspects could inject code in the right places to add and remove the instances from the list. I might have to look into this and see if it is even possible.

Reference:
Game Programming Gems III
Java 5 Generics
Eclipse AspectJ

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The Internet Public Library

I may be late on this but I found this site and it looks pretty cool: link here. It contains some good information about Blogs and has some great categories on popular blogs on the internet.

Buying Memory

I just went to buy some memory and saw something I have not noticed in the past. The memory speed calculation is pretty interesting. I of course had to find the fastest memory before I purchased. What amazed me was the difference from brand to brand and even more interesting is that some brands do not even list their speeds! I endedd up buying two more gigabytes ram giving me a total of 3GB. It had what looks like the best CAS latency value of 2-3-2-5.

These are relatively important timing terms:

  1. tRP – The time required to switch internal memory banks. (RAS Precharge)
  2. tRCD – The time required between /RAS (Row Address Select) and /CAS (Column Address Select) access.
  3. tAC – The amount of time necessary to “prepare” for the next output in burst mode.
  4. tCAC – The Column Access Time.
  5. tCL – (or CL) CAS Latency.
  6. tCLK – The Length of a Clock Cycle.
  7. RAS – Row Address Strobe or Row Address Select.
  8. CAS – Column Address Strobe or Column Address Select.
  9. Read Cycle Time – The time required to make data ready by the next clock cycle in burst mode.

Note #1: tRAC (Random Access Time) is calculated as tRCD + tCAC = tRAC
Note #2: RAS and CAS normally appear in technical manuals with an over-line as in RAS or CAS.

Reference Link: link here

Java and Notes Developers do not mix…huh?

I just posted a response over at Ed Brill’s blog about how I think of the world differently with regards to Hannover and its impact on the Notes community. Even when I was a Domino developer customer I was knee deep in Java for many of the Web applications. I also did tons of Java Script. That said, I think we need to sit back and watch how a whole new world of opportunity comes to the Domino and Notes community. Composite Applications in Hannover are going to change the entire perception of the closed Notes architecture. You are now going to be able to leverage all of your existing application knowledge in a whole new architecture – Eclipse.

By the way, did anyone see Maureen Leland’s presentation about designer at Lotusphere? Enough said…

Ok, in case you didn’t check here for a presentation on Workplace Designer.

Upgraded the PC!

I upgraded my PC and it was well worth the money. For around $600 I have a new PC. I never suffer from disk space so that was fine, I stayed with my 1GB of RAM (which I may bump up) and the only things I changed were the CPU, Graphics Card and a new internal DVD writer.

I upgraded the main CPU from a Celeron 1.7ghz to a normal Pentium 3.2ghz. Amazing difference. My test was simple, a screen I have been working on in TrueSpace 6.6 took basically 8.5 minutes to render in full quality mode. With the new CPU it takes only 9 seconds. This is a huge difference in productivity

I then went away from the GeForce 400M to the new GeForce 7800. This bad bear is pretty amazing coming in at 256MB and AGP 8x. I had to stick with AGP because the motherboard does not support PCI Express

Lastly, I upgraded to the Plextor PX-716SA 16X Int Dual Layer Sata Drive (P67-1118 ). This drive is highly rated and only costs $100 (before the rebate).

So in short, I am glad I bought a good enough motherboard years ago (ABIT) that supported the full range on Pentiums for the 478 model.

Jeff McAffer gets Top Committer Award at Eclipse Con

Fellow colleague Jeff McAffer got an honorable mention for the Top Committer Award at Eclipse Con this week. Outside of mentions like Erich Gamma and Ed Burnette, he was the only guy I personally knew.