FTP synchronization. How to update your sites via FTP?

Upload your site via FTP. This is usual offer bundled with web hosting solutions. Nowadays it is mostly SFTP, for secure communication.

There are various sophisticated FTP synchronization solutions. But you can also use simple LFTP script to achieve the same. The lftp command is available in most of the Linux distributions.

Here is example script I put in some of the projects which are deployed as pure static HTML/CSS:

lftp -u username -e "set ssl:verify-certificate no; mirror --reverse --delete --only-newer -v site_source_dir /; exit" ftp.somewebhosting.org

It works like a charm thanks to this reverse mirror approach.

But there are better ways of pushing changes to your static sites. If your are interested, watch out the next post which should appear soon.

Tadedon - solid ground for any Java application

Some time ago I started project called tadedon. The name is coined by my little son Alan (Polish), and I assume it is short, unique, and easy to remember.

The whole projects consists of several maven modules, which are intended to be flexible tools for solving common problems. Each module is built on top of library like Guice, GWT, commons-configuration, etc. Tadedon modules shouldn't be considered as extensions to these libraries, but rather as a thin layer of code which allows to use these libraries in special contexts. Here is an example of tadedon-guice-servlet-mock module which supports unit testing of Guice Servlet Modules without the need of real servlet container.

I have already released version 1.0. Now tadedon needs some attention - it should attract more users, and developers. Any contributions are welcome. Putting tadedon modules into maven central repository seems the most important goal right now.

gwt-servlet-war project, no more annoying gwt-servlet in the classpath

All the GWT libraries are available in the central maven repositories now. There are 4 different jars for single platform (gwt-user, gwt-dev, gwt-dev with platform classifier (thus there is even more jars the 4) and gwt-servlet.

If you are developing gwt application which will be packaged as war, these libraries should be included in pom.xml with something like this:

 <dependencies>
   <dependency>
     <groupId>com.google.gwt</groupId>
     <artifactId>gwt-user</artifactId>
     <version>${gwtVersion}</version>
     <scope>provided</scope>
   </dependency>
   <dependency>
     <groupId>com.google.gwt</groupId>
     <artifactId>gwt-dev</artifactId>
     <version>${gwtVersion}</version>
     <classifier>${platform}-libs</classifier>
     <type>zip</type>
     <scope>provided</scope>
   </dependency>
   <dependency>
     <groupId>com.google.gwt</groupId>
     <artifactId>gwt-dev</artifactId>
     <version>${gwtVersion}</version>
     <classifier>${platform}</classifier>
     <scope>provided</scope>
   </dependency>
   <dependency>
     <groupId>com.google.gwt</groupId>
     <artifactId>gwt-servlet</artifactId>
     <version>${gwtVersion}</version>
   </dependency>
 </dependencies>

GWT jars marked with provided will be available during development, but not packaged into war. This approach have only one drawback, core gwt classes are present in both - gwt-user, and gwt-servlet jar in the same time. In case of developing project in eclipse with m2eclipse plugin it leads to very annoying behavior (not finding sources, showing two candidate types with the same name, etc.).

I have created new gwt-servlet-war project to overcome this problem. The idea is very simple. Instead of the last gwt-servlet dependency from above example, one should put:

   <dependency>
     <groupId>pl.ncdc.gwt</groupId>
     <artifactId>gwt-servlet-war</artifactId>
     <version>${gwtVersion}</version>
     <type>war</type>
   </dependency>

After this change, war packaging will be supported by so called "war overlays" where wars specified as dependencies are merged into war being built.

And guess what gwt-servlet-war contains? Only gwt-servlet library in WEB-INF/lib. Thus project is in fact single pom.xml. Anyway It have to be packaged according to gwt versioning scheme.

If anyone have any idea how to set up maven repository on top of code.google.com's subversion, please contribute it to the project. Maybe I should promote this jar to be put in central maven repo, or rather suggest people responsible for putting gwt artifacts there to provide something of this kind along the line?

Maven google code upload plugin

The project is located here.

Example setup (works well with my projects) looks like:

<plugin>
  <groupId>org.riedelcastro</groupId>
  <artifactId>maven-gcupload-plugin</artifactId>
  <version>1.0</version>
  <configuration>
    <uploads>
      <upload>
        <extensions>jar</extensions>
        <labels>Featured,Type-Archive,OpSys-All</labels>  
      </upload>
      <upload>
        <extensions>jar</extensions>
        <postfix>sources</postfix>
        <labels>Featured,Type-Source,OpSys-All</labels>
      </upload>
      <upload>
        <extensions>jar</extensions>
        <postfix>javadoc</postfix>
        <labels>Featured,Type-Docs,OpSys-All</labels>
      </upload>
    </uploads>
  </configuration>
</plugin>

The gcupload:gcupload maven target is added to our Hudson. We have differentia-javaica release build which takes care of everything - deploying jars to our Nexus as well as putting them to Google Code.

Differentia Javaica

I started a new project called differentia-javaica. Here is the quote from the original description:

The aim of this project is to compare two java source codes and check if they are equal. It is not a simple diff. It uses ANTLR to construct two Abstract Source Trees for java types and eventually compare these trees. As a consequence white spaces and comments will not affect comparison. Reordering of elements in source code will be treated as difference though.

This kind of comparison is especially helpful when writing unit tests for java source code generators. When we have expected source code it is possible to check if it equals to generated source code.

We are writing some Java source code generators right now at NCDC and this tools is quite helpful in unit testing. Thus we want to share it with community.

Finding duplicates in array of integer numbers

Some time ago I spotted job offer (polish) posted by a friend of mine. Marek initiated a start up company and now is looking for a new member of his team. The offer is very interesting because it contains a kind of "applicant sieve". :)

There is a task to do for a person who wants to apply - algorithm implemented in any language which solves the following problem:

Having integer numbers array of size N which contains values from range 1 to N, find if there are any duplicated values.

The problem is quite interesting because there are many possible solutions of different properties. Though I am not looking for a new job, I tried to solve the problem. Simple solutions are quite obvious, others which could be called "optimal" become much more complicated. When taking some restrictions into account like O(n) computational complexity, O(1) memory consumption and so on, the solution becomes strightforward. I wonder if it is possible to write an algorithm which will take all restrictions into account and will treat the input array as read-only structure. I tried to implement it, but I failed. :(

In order to achieve the goal I started with testing code. Having some different algorithms I decided to compare their "real life" effectiveness. As you probably know microbenchmarking is loosely connected with real life. :) Anyway writhing them is a good fun. I decided to put everything as open source project called finding-duplicates. I hope Marek won't be angry - the project is spoiling his offer. :) The task was posted some time ago, I hope he has employed someone already. I am quite surprised by the reactions this offer has caused when mentioned on Jacek Laskowski's blog. This is the reason I hope that some people could be interested in my project. I hope that all this buzz will sooner or later bring Marek more candidates. :)

If you have more "optimal" solution then one collected here, just send it to me, or better drop me a line and I will make you a member of this project. I wonder if I have collected all the possible categories of solutions. Special thantks to Adam Woźniak for his implementation. :)

With one additional assumption - array elements are less then N - it would be possible to use algorithm described here, and here. Probably it could be somehow adapted to Marek's problem. For example by adding "virtual" last element to the array. It should has the value less then N (it could be even random number) if we find duplicate and its value is the same as the last element value, then one more pass through the array would be required. Any ideas?

Eclipse Ganymede - rejoicing in virility

Origins of the meme

The phrase "rejoicing in virility" is translated etymology of term ganymede. Ganymedes was the most handsome among mortals - a mythical hero of ancient Greek cluture.

Term ganymede is associated with some memes - probably quite selfish ones. As long as they are referred in this post and as they are understood by readers of this post I assume the last statement being proved. :) In evolution of culture some old memes die, some other are born, some other gain a new life.

Memes of ancient Greek culture often influence birth of new memes and then persist somehow within new ideas. Soon after Galileo discovered moons of Jupiter, one of them was named Ganymede.

A new meme associated with term Ganymede has been born recently. I suppose it's life will be relatively short (about year), although very intensive. For sure it will cause creation of new memes.

If I was asked some time ago what eclipse is, I would not have much problem with the answer - another Java IDE. Now eclipse is much more. We can call it a platform for hosting different development components. Every day connotations of the term eclipse grow like branches of a big tree.

As eclipse is astronomical term, the ganymede used for naming software follows this convention. If I was asked what this Ganymede is I would say: it is an attempt to steer some specific evolutionary process associated with software development. An attempt to stop this evolution for a while. An attempt to match different software projects in the shape they interoperate the best. There is a reason the platform is called ecosystem.

It is not the first time that Eclipse Foundation freezes the evolution at some specific stage. It is called "simultaneous releases" and so far we had two previous releases of this kind also named after moons of Jupiter - Calisto and Europa.

This introduction was long and boring. :) What really interest me as [not-so-]pragmatic programmer, and probably interests you who is reading this post right now, is a comparison between Ganymede and Europa.

Downloading

Ganymede could be downloaded from a new site. What is nice here - special link for downloading Linux AMD64 version. Finding proper version for this platform was a pain in the past. I have downloaded Mac OS X version numbered as RC3.

Launching

I have checked that the Mac OS X version comes with eclipse.ini file adjusted for more realistic usage scenario

-Xms40m
-Xmx512m
-XX:MaxPermSize=256m

Good, I won't have to tweak it by hand. It was probably fixed also in the latest Europa bundles, but for sure not in the initial ones.

During eclipse start I spotted new splash screen, quite interesting to see what else could be arranged with the same conceptual graphical elements and the same color scheme.

My workspace seems to be upgraded quite smoothly. From the first sight I cannot see anything new in eclipse appearance. Although generally being liberal I tend to be conservative on some topics. One of them is look and behavior of tools I am using and I got use to. It is not about software only. It could be about hammer or screwdriver, any extension of human body or human mind. :)

Installing plugins

Although version Eclipse IDE for Java EE Developers provides quite comprehensive development environment there are still some missing futures I use on day to day basis.

Installation of eclipse plugins has been completely redesigned. Now it is simpler and clearer and works without much ambiguity as it use to be. New option of Automatic Updates was added to general eclipse preferences, nice. However there seems to be some software update related bug in RC3, eclipse is trying to install the same upgrades forever. Fortunately when I came back to eclipse.org there was RC4 release available which upgrades without any problem.

I see only one drawback comparing to previous Software Updates functionality. Selecting plugin to install will not show brief description. The description could be find in General Information after right clicking and choosing Properties.

Ganymede comes with dozens of new features comparing to Europa. Some of them I have been using already however specifying Update Site manually. Now these releases are synchronized available from predefined sources. I will just name things important to me:

• Remot System Explorer (included by default in Java EE bundle)
• SVN Team Provider
• Usage Data Collector (included by default)

The last feature is quite interesting:

The Usage Data Collector collects information about how individuals are using the Eclipse platform. This information is periodically uploaded to servers hosted by The Eclipse Foundation (though this is configurable). The intent is to use this data to help committers and organizations better understand how developers are using Eclipse.

Target Users of the Data:

• Users of Eclipse
• Committers working on Eclipse projects
• ISVs and organization creating Eclipse based software
• Enterprise IT departments that make extensive use of Eclipse Foundation
• Academic researchers that want to study how developer work Data to Be Collected

Captured data is associated with a user through a combination of workstation and workspace ids that are automatically generated by the collector. This identification is not tied to any personal information about the user.

The usage data monitors:

• Start up and shutdown times of a workspace
• What is being used and when (timestamp), including
  1. Loaded bundles
  2. Commands accessed via keyboard shortcuts
  3. Actions invoked via menus or toolbars
  4. Perspective changes
  5. View usage
  6. Editor usage

Where possible, the usage data collector also capture the symbolic name and version of the bundle contributing the command/action/perspective/view/editor.

This functionality reminds me Debian Popularity Contents. Did I say something about evolution. It is definitely a kind of convergence.

Subversive plugin is now part of the distribution. Unfortunately it still depends on connectors provided by Polarion. I added:

http://www.polarion.org/projects/subversive/download/eclipse/2.0/update-site/

to my Update Sites, nice feature here (or rather lack of annoyance :) ) - I am not longer forced to provide Site Name - just URL.

I installed SVNKit 1.1.7.

Now it is a time for Maven Integration Plugin plugin, I installed:

• Maven Integration for Eclipse
• Maven POM XML Editor
• Maven: The Definitive Guide book

BTW there is a proposal to create Eclipse Integration for Apache Maven (IAM) under the umbrella of the Eclipse Foundation, great.

I installed additional plugins without any problem:

• EclipseWiki - the latest version is integrated with Eclipse Spellchecker
• Java2HTML - the plugin is quite old, but works with eclipse 3.4 without any problem
• Apache Directory Studio

And now a little bit about new features I can see from the first sight:

New features and other remarks

Unfortunately the most annoying bug (at least for Mac OS X users) of the latest Europa updates remains in Ganymede (I suppose it is connected with SWT). :(

I can see italics text in case of attributes shown in XML editor, interesting.

While browsing available views and perspectives I spotted some interesting things I hadn't tried.

• Palette - I suppose it is available to support diagram editin
• Snippets - something new
• Templates - looks like new interface to the old functionality
• TCP/IP Monitor - it is from Debug Perspective, great I hope it will replace external sniffer for debugging networking code
• JPA related views
• Execution Plan in SQL Development perspective

That's all for now. I hope to write more when I will start using these new features. So far ganymede looks very promising and interesting.

Conclusion

Valueable memes never die. :) Eclipse Foundation is quite good in spreading own memes. It is very interesting to see what kind of "social engineering" is used in order to attract mass attention for products of open source movement . Firefox is a perfect example with todays Download Day 2008.