Command Pattern – Queuing Commands

This is a slight variation of the previous example, with a much different result. If you look at the source you’ll see that only the click handlers of the buttons have changed.

Now, whenever you click a green, red, or blue button each action will queue up waiting for you to click the black button. Once you click the black button, every action queued up (meaning each circle waiting to be created) will execute all at the same time.

View Queued Commands example
source

Tags: design patterns

Command Pattern – Undo and Command Stack

As requested, here’s a demo of the command pattern in action. This example shows how to use the Command Pattern to undo an action. Please watch the video in the previous post before browsing through this source.

Try to focus on how the commands are all added into the command stack, then you’ll see how the stack can be used for undoing, redoing, logging actions, queuing actions, and all sorts of other useful stuff

Click on the green, red, and blue boxes to create new circles. Click on the black box to undo.

source

Tags: design patterns

ActionScript 3 – Command Pattern and Interfaces

Click to view the video in a pop-up. Right-click and “save as” to download the video to your hard drive.

Watch Video Tutorial on Command Pattern and Interfaces

Tags: design patterns

Server Woes and Forum Status

You may have noticed that my site went down for a few hours yesterday and that forum.papervision3d.org is still down. Here’s what happened:

1. When I created the forum a couple months ago, I used ssh to move a bunch of files between domains
2. Yesterday, I updated to wordpress 2.71 and thought it would be a good time to reboot the server for kicks
3. httpd wouldn’t come back on (meaning you couldn’t browse to any of my sites) after the reboot because Plesk screwed up some conf files either when Plesk updated to a newer version or due to the ssh madness I played around with
4. I cleaned up some stuff in plesk, including removing the old forum.pv3d.org domain
5. I found out that when you delete a domain in Plesk, Plesk also deletes all related databases (without warning). I had forgotten I created the original forum database under the forum.pv3d.org domain (not forum.papervision3d.org)
6. My buddy Beto from rojored.com helped get my blog back up by doing some server voodoo (thanks Beto)
7. I thought I set up automatic backups in phpbb3, but I must have missed a step because I can’t find them anywhere
8. The forum is down and as far as I can tell I don’t have a backup of the database (mediatemple doesn’t do automatic backups on dv servers)

So, bottom line, I screwed up royally on this. I should’ve confirmed I had database backups before doing anything with Plesk. I’m upset that Plesk thinks it’s a good idea to delete databases when you delete a domain (especially without a warning), but I have to take most of the blame myself.

I’ll try to get the forums reinstalled next week when I get a spare moment. I’ve already wasted way too many hours trying to resurrect them from the dead. Everyone will have to create a new account and all the content will be gone (I guess you can use google’s cache for individual pages while it’s still available) so we’ll have to start fresh. I’m open to suggestions on how to improve from the first install if you have any.

Oh, and my wife sprained her ankle playing basketball this morning so I’m going to be a bit of a Mr. Mom for the next few days

Tags: off-topic