Installing RMagick seems to be a major pain in the ass… On all systems i got my hands on.
On a fresh Ubuntu Feisty Fawn gems presented me this:
configure: error: C compiler cannot create executables
Hrmpf, ImageMagick was installed, gcc for sure… What did i miss?
1. sudo apt-get install imagemagick 2. sudo apt-get install libmagick9-dev 3. sudo gem install rmagick
Well, the 2nd one…. Found here.
I was in need of tokenizing some comma delimited data within an Oracle Database. A pity, there’s no split for a varchar2 like java.lang.String.split. I could have used Java in the database, but that would be lame, too.j
I found this little function which uses pipelined results, that is, it returns his results while being processed and furthermore, it can be used as a table in a from clause. Great as i need no extra code to check my values in my case.
So here it is:
CREATE OR REPLACE TYPE split_tbl AS TABLE OF VARCHAR2(32767); / show errors; CREATE OR REPLACE FUNCTION f_split ( p_list VARCHAR2, p_del VARCHAR2 := ',' ) RETURN split_tbl pipelined IS l_idx PLS_INTEGER; l_list VARCHAR2(32767) := p_list; l_value VARCHAR2(32767); BEGIN LOOP l_idx := INSTR(l_list,p_del); IF l_idx > 0 THEN pipe ROW(LTRIM(RTRIM(SUBSTR(l_list,1,l_idx-1)))); l_list := SUBSTR(l_list,l_idx+LENGTH(p_del)); ELSE pipe ROW(LTRIM(RTRIM(l_list))); EXIT; END IF; END LOOP; RETURN; END f_split; / show errors; |
This thing takes two parameters, the first one the string to be tokenized, the second an optional delimiter. It returns all tokens trimmed as a row for each token.
Kudos to Scott Stephens.
I always thought that the Java Thread API is something… strange. If you work in a frontend application, things like running long-running tasks in the back without having the GUI ugly frozen and not responding should be somewhat simpler.
SwingWorker has been around for quite a time but made it just recently into the core API (Java6). Furthermore i don’t think that it’s the right thing for performing enduring tasks like checking for mail and pushing a result with a second thread into a database, for example.
Don’t get me wrong, i use SwingWorker quite often, but it didn’t fit my needs and furthermore, i wanted to learn more about Java Threads.
My goal / task was a little daemon that regularly checks an email account and a samba share for some files, load them into an Oracle Database and executes a longer running db procedure. The checking should be suspendable and stoppable independently, the configuration should be reloadable.
I throw some interfaces and abstract classes at the vm and boom, it was that simple 😉
Things i’ve learned:
The following demo can start 7 producers and one consumer, both are synchronized via a BlockingQueue (i actually used a SynchronousQueue at work, as the files must only be removed if they were taken by the db). Both the producers and consumers can be suspended, resumed and stopped. I never ever will start a thread by hand again if not necessary. The threads are managed by an ExecutorService.
For the tasked mentioned above this thing works fine. If anyone comes up with a better idea, let me know.
I had fun to write it, maybe you have fun to read. Be aware, the program is not a good example of organizing classes, i put everything in one file just for the sake of being a demo.
But apart from that, the demo could serve as an example of what came to Java with Java 5 and 6 as i use a lot of generics, enums and enhanced for loops, in case you haven’t seen this.
To compile and run the stuff you need at least a Java5 JDK (get it here, download this file JThreadDemo.zip, unzip it and type
javac snow/white/JThreadDemo.java java snow.white.JThreadDemo
If you read this, i’ll guess you’re familiar with the JDK, java packages and the whole crap.
Get the whole fun after the click:
…or any other thing that responds to wol (wake on lan) from a Mac OS X thingy:
Just use Wake550.
Some people tend to mock Mac OS X in favour of some other Unixes, but i like it… For me, it sucks least.
Today i took some relativly small external firewire drives (250 GB each), attached them to my “always on” serving Mac Mini and it took less than 5 minutes to build a RAID on two external drive.
I’ve choosen a RAID 1 configuration as i want to use the drives for backup purpose. Mainly for my music collection and for the forthcoming Time Machine with Mac OS X Leopard.
As there is no possibility in OS X to share external drives (wtf, i know…) i recommend Sharepoints for greater flexibility with AFP and SMB shares.