Maybe, when requiring your just created extension, you get a LoadError. If it is the first time you require it, it is quite likely that you have not followed JRuby requiring conventions. If you want to know how require works, you can find the best documentation ever about it in the comment before org.jruby.runtime.load.LoadService class.
photo credit: cesarastudillo
Note: not code in this post, but you can see the code in Github. Follow the links!
Writing a JRuby extension is very easy, but there are almost not post out there about it. As far as I know, there is only one, Ola’s. It is a really good tutorial indeed, but it lacks some details that might be not-that-easy to solve. Please, take some time to read it and, if some details are different, do follow Ola’s way.
Everything’s ready now, so let’s start talking about BasicLibraryService. If you take a look at Nokogiri4J sourcecode, in ext/java/nokogiri folder, you will see a NokogiriService.java file. NokogiriService implements BasicLibraryService. This interface consists only of the method basicLoad which receives a Ruby object.
We will use this method to define classes and methods in the Ruby world. For defining a module, defineModule method is used with the name of the module. After that, modules and classes under that module can be defined easily by using the methods defineModuleUnder, which takes the name as parameter, and defineClassUnder, which takes the name and few parameters more. Let’s dive into it.
defineClassUnder needs three arguments. The first one is the class’ name. The second, is the parent class. If you have defined it previously, just passed it, otherwise use RubyObject by calling the method getObject on the Ruby instance. The third parameter is an ObjectAllocator. ObjectAllocators returns intances of the classes in Java world. When instantiating Nokogiri::XML::Comment in Ruby world, JRuby will ask the ObjectAllocator for an instance of the Java class. It passes a Ruby object and the RubyClass being instantiated to the allocate method in the ObjectAllocator (more on RubyClass in following posts).
Finally, we will need to define some methods. Easiest way is by using the defineAnnotatedMethods. It takes a Java class as parameter. For knowing what this method does, you need to know a bit more about @JRubyMethod annotation (more on it in following post, have you realized the “Part I” in the title?). As you define methods, you may need to undefine some in a subclass. So easy! Use the undefineMethod method, which takes the name of the method as parameter (surprisingly, it undefines a method by redefining it!).
Next time, Implementing your first class.
Ok. My fault. Now, let’s go get some work done.
First, if you haven’t done it, read the previous post about helping nokogiri and forgot about the script and memory leak. It seems that there are more important issues, so let’s fix them first. First run jruby test/test_jruby.rb from Nokogiri root. You’ll see a lot of errors (27 by now) and failures (14). Choose one, and get it green. After that, send me a pull request.
Ok. That sounds simple, but what if the number of errors or failures raises? The rule I use is simple: keep the sum of both numbers going down and having a failure is better than having an error.
On the other hand, if you take a look at test/test_jruby.rb, you’ll see that not every test is in there. There is a reason for that. Even keeping the number of test low, you get a lot of errors/failures. If that annoys me with just 50 failures, imagine if I had a couple of hundreds errors. When all is right, I’ll add some more to keep the fun on.
Photo by Paul Johnston.
First things first, if you wanna help, you’ll need to clone the git repo. Just:
git clone git://github.com/tenderlove/nokogiri.git
cd nokogiri
git checkout --track -b java origin/java
Install the dependencies. Just:
rake install:deps
Because it uses some native libraries, you’ll need to do that with MRI. Finally, you’ll need to generate some files, just run jruby -S rake java:spec. For having a hprof file, you’ll need to run this script with the following command:
jr -J-Xmx32m -J-XX:+HeapDumpOnOutOfMemoryError nokogiri_doc_frag.rb
-J-Xmx32m limits the heap space to 32 Mb, and the other options makes the JVM to write a hprof file when a OutOfMemoryError is thrown. After that, you can inspect that file with the profiler you can find in NetBeans.
In next post, I’ll comment where I think the problem is.
Hi, all,
sorry for the silence all these months, but I’ve been working hard on Nokogiri. First things first, it is not complete yet. Anyway, I’m gonna tell you how to build a gem and start working with it.
photo credit: Matthew Byrne
Clone the repo and checkout the java branch.
git clone git://github.com/tenderlove/nokogiri.git
git checkout --track -b java origin/java
Next step: build the gem. As easy as jruby -S rake java:gem. Maybe, you need to install rexical and racc. jruby -S rake install:deps would do.
Finally, you have a gem in the pkg folder. Install it, and you’re done.
Updated: Take a look here if you wanna help.
It’s been long time since last status update, but there are some things to tell, so here I am.
Thankfully, this year I’m a GSoC student again (and my mentor is Tom too). The main part of my project would be porting Nokogiri to JRuby, so I haven’t code for RMagick for a while now.
Let’s start with the status update then.
Nokogiri
I’ve been working on Nokogiri for a while. I forked Charles’ repo in Github, and I’ve implemented some cool features. For example, today I got my XML::Reader implementation to pass all tests in test_reader.rb. I hope I’ll be able to make a release this month (cross your fingers).
On the other hand, I got my first patch accepted in Nokogiri’s main repo.
RMagick4J
Not to much work done here, sorry. I haven’t code anything for a while now. Migrating from mercurial to git is already planned, but before that I would like to do a few commits more. Anyway, I’m quite happy with this project. Some people are using it and reporting bugs (in the end, those little things are all that matters). What else can I ask for?
Please, if you find a bug, report it here.
MagickWand
Tim Hunter (creator of RMagick) released MagickWand recently. I’ve been considering porting it to JRuby too. I have to take a deeper look at the C code, but, by now, I think it could be a good way to lead RMagick4J development. If finally I port it, I will split RMagick4J in two projects (Magick4J and RMagick4J). This way, MagickWand4J and RMagick4J would share the same java codebase, as MagickWand and RMagick share ImageMagick.
ruby2java
Take a look here. Awesome, isn’t it? And as soon as I have some time to work on it, siesta will be out too…
P.D. By the way, no more personal stuff in this blog. That stuff is now here, and only in Spanish (sorry about that).
Two days ago, I was talking about Susan Boyle with a friend. I do not like her, my friend didn't even know who she is. I told her about Susan, she has a good voice (not a great one) and she can sing pretty well. The only difference is that she is quite ugly (in Spanish I would say that she is uglier than hitting your own father with a sweaty sock). Her answer was pretty simple: It's all about expectations.
She said that by looking at her, my expectations were low, so when she sang even with a good-but-not-extraordinary-as-they-want-us-to-believe voice.
Other way of making things look better is the Bluetooth-Cooper theorem ("Averything is better with bluetooth"), in this case, with the Jackson-Vader corollary:
[youtube]http://www.youtube.com/watch?v=rxL3Yvf-d58[/youtube]
RMagick4J 0.3.7 Happy Birthmonth has been released!
RMagick is a Ruby binding to ImageMagick and GraphicsMagick. RMagick4J implements ImageMagick functionality and the C portions of RMagick for use with JRuby.
Current stable version: 0.3.7
Project URL: http://kenai.com/projects/rmagick4j
Installation: gem install rmagick4j
New effects:
(I think that's all that you need to use simple_captcha)
Major bugs resolved:
Furthermore, RMagick4J does not depend on jhlabs library anymore (the gem has lost some weight!).
Thanks to:
Please try out your applications with rmagick4j and help us provide feedback (even birthmonth cake!). It is our goal to make a fully-compatible implementation of RMagick4j in JRuby.
You have some image examples here: http://www.serabe.com/rmagick4j
This is a very special release, cause March is my birthmonth.
Happy Birthmonth to:
This week I've been fixing some bugs, adding some minor effects and adding wave effect.
In order to add wave effect I've had to read a lot of ImageMagick code. Lucky me, there was an if that made all too much simpler. Unlucky me, I didn't realize until the third reading-code day.
Anyway, after sweating blood, here you are the images:
| RMagick | RMagick4J |
| original | |
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|
| charcoal 0.75 | |
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| negate | |
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| normalize | |
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| blur_image 2 | |
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| wave | |
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