In the tech-oriented area of the internet, Google Chrome caused more heavy waves than any comparable event before. Reports and discussions surfaced everywhere. According to one source, Google Chrome already had a market share of over 1% after only a few hours - probably caused by curiosity like mine.

Here are some topics - some with a link - I find interesting:

• First impressions
• Why Google releases a browser of its own
• What Chrome can do the others cannot
• Chrome’s effect not only on the browser market
• Security issues of the beta
• Chrome is calling home
• How to prevent Chrome from transmitting data to Google (in German)
• How fast is Chrome really
• Are all of Chrome’s components open source
• Where’re the Mac and Linux versions
• Is the beta of Google Chrome suited for Joe Average
• Lots of opinions on Chrome
• Google, a $100,000 misunderstanding (in German)

Installation and setup

Of course, I was curious too and have tried to download the software. I was able to download ChromeSetup.exe thru a proxy that required authentication, but the subsequent download of the software proper failed due to the fact, that ChromeSetup wasn’t able to handle a proxy that required authentication. It worked with a proxy that didn’t require authentication though. Strange enough, after installation Chrome is able to handle a proxy with authentication.

What I really don’t like is that Chrome is transmitting a unique Id back to Google, so that’s easy to track where the user has been on the internet. To prevent this, change two entries in the file Local State of the Google Chrome installation. Although I can understand Google’s motivation for this, a complete user profile is not something I want Google to have, as I don’t have any control over it.

Bug fixes and more from Google

Google has already addressed some concerns about the EULA and a security problem within a very short period of time, so I hope they will be equally fast fixing new problems as they occur. What they really should address before the first official release is the ability of the user to control in an easy way, what data he wants Google to receive about his surfing habits. If in doubt, don’t send anything. They should not only explain what data is stored on their servers, but give the users a choice.

On the same page, I don’t like how they handle the installation of GoogleUpdate.exe as a service, even though it’s mentioned in section 12 of the Google Terms of Service. It’s not mentioned during the installation of Chrome, that it doesn’t go away after I’ve uninstalled Chrome. It simply stays there and is started every time I log into my computer. Manually editing the Windows registry seems to be required if you want to get rid of the GoogleUpdate service. GoogleUpdate is installed and used by a lot of other Google software too.

It’s fast

After a couple of days using Chrome I’ve to say that I’m impressed by its speed. This doesn’t come from the benchmarks saying that it’s mostly faster than the competition, but from my experiences working with it. It’s not only starting up faster than Firefox 3.0.1, but feels a lot snappier too. Browsing the internet with Chrome is definitely fun.

It’s beta software and not finished yet

The current version of Chrome is an early beta version, so don’t expect that it will not have problems. It’s something you should use only if you’re aware of the risks involved in using beta software. It might have security problems and bugs that can lead to lost data. It shouldn’t be used in production environments.

It’s also missing a lot of features I’m used to expect from other browser like Mozilla Firefox. All the nice little ad-ons are still missing. Especially Adblock Plus is missed here, because only without it I’ve realized how ugly the internet really is. And have you tried to read a RSS feed? It doesn’t work yet.

Conclusion

Google Chrome looks like one piece of software I might love to use one day. Most features present today are impressive already. It will then be added to the list of software from Google I’m using on a regular basis today. I’m using Google software for:

• developing AJAX applications in Java with Google Web Toolkit
• wiring dependencies with the dependency injection framework Google Guice
• extending the Java Collections Framework with Google Collections

These software products I use that come from Google are great, and I like to use them. Chrome is a little bit different as it comes with a price, that not everybody is willing to pay: you give Google the ability to create a user profile of you and you can’t control what they are doing with it. If Chrome has the ability to turn this off, then it might be for me.

The tool

Although I wasn’t involved in the selection process, there’re good reasons for TOS, some were decisive:

• it’s an Open Source solution
• there’s a branch office in our country
• based on the Java and Eclipse platform
• active community
• training and support offerings

I’ve had really good experiences with our main Talend contact over here. Based on a couple of workshops and support cases I have to say that he was of great help for our project.

Depending on were you come from and what you need, some of the points speaking in favor of TOS for us might speak against it for you. The good thing is, there’re enough solutions/products out there, maybe even one for you. But it might not be TOS. If you’re not sure if an ETL solution is right for you, maybe this article by J. Mundy helps.

The staging area

The database system used for the staging area is IBM DB2 Express-C. The staging area is cleared before every import and has two stages itself:

1. data is loaded into tables that reflect the schemas of the CSV files; all fields are VARCHAR fields
2. then, the data is converted into the proper types, e.g. DECIMAL(15,2), DATE, INTEGER, …

The table schemas for the tables in stage one and stage two have a couple more fields than the CSV schemas:

• ID_ROW identifies the data row from the CSV file
• STATUS holds information regarding the correctness of the data (and thus if it has been successfully written to the stage-two table)
• ERRMSG contains a detailed description on the problem (if any)

There’re many CSV files to import into the staging area, but the basic process is the same for all. The TOS job that does the work looks like this:

I’ll give you a short description of the process:

• first line imports the CSV data into the stage-one table
  • the CSV file is read in
  • because the CSV schema and the stage-one table schema differ (more fields, see above) we map the CSV schema to the table schema
  • each row gets the additional ID_ROW field filled
  • the data is written to the stage-one table
• the data now residing in the stage-one table is converted and written to the stage-two table
  • stage-one table data is read in
  • the conversion to the proper types takes place; the status and the error messages are generated here
  • all problem rows are sorted out, based on the content in STATUS
  • the rows without problems are written to the stage-two table
• error logging and reporting
  • all rows that didn’t make it to the stage-two table are updated in the stage-one table to have the correct STATUS and ERRMSG set
  • problematic rows are written to the console for this example

TOS components

TOS basically lets you work with components. You place them on the screen and connect them, enter some information into the properties of these components, and then TOS generates Java source code ready to compile and run. Once generated, you cannot alter the Java source code directly. You have to do it by altering the components properties. Some informations like schemas for CSV files and database tables, database connection info, etc. can be stored in a repository and you can connect them with components. That’s nice if you need the same information in more than one place.

For the type conversions, we use a component called tJavaRow. It has two main properties (called settings in TOS):

• the input and output schemas
• a text area that contains the Java source code executed by this component

I’ll explain later, why we use this really basic component instead of a more fancy one like tMap that seems to do the job more nicely. It doesn’t. Anyhow, the Java source code looks like this:

C_OUT.STATUS = "OK";
C_OUT.ERRMSG = null;
convert(C_IN, C_OUT, "ID_ROW", "toField", "ID_ROW");
convert(C_IN, C_OUT, "FIELD_ONE", "toNumber", "SignedNumber", ",");
convert(C_IN, C_OUT, "FIELD_TWO", "toNormString");
convert(...);

A central conversion routine written in Java is used for all conversions. It does the exception handling in case of a problem (e.g. sets the fields STATUS and ERRMSG) and controls the conversion. The input and output Java data objects are passed in as well as the field names, the name of the conversion routine, and additional parameters. The convert method does the work by using the Java Reflection API to look up fields and methods. The advantage is that it simplifies the exception handling, but it comes with a price: there’s no type safety anymore, i.e. problems are reported at run time, not compile time. We automatically generate the calls from a repository that contains all necessary information. The Java source code is simply copied, not written by hand.

The tMap component on the other hand is nice for ad-hoc mapping and conversion of a few fields, but isn’t really fit for the task otherwise. It might look good during a presentation/sale pitch, but it’s just too painful to work with. That’s because you have to select every field where you want to enter some functionality. It’s just too many clicks. And guess what, if you have to refactor you code, you’ll start all over again, i.e. go to every output field and do the refactoring manually. Imagine a schema with couple of hundred fields and you go nuts.

What I think so far

I’ve only written about a small number of things regarding TOS, but they were important for this part of the project. The import of data from CSV files into the DB2 database is possible within the requirements given above. I didn’t have performance issues related to TOS. The visual components are nice, but sometimes get in the way of working efficiently. What I really want to see is the possibility to edit the components settings with a text editor as a whole in addition to the form based entry.

This information is based on TOS 2.3.2.r12707. Things that were broken in this release were

• HTML documentation was not generated at all
• given exception locations weren’t in sync with generated source code
• export project didn’t work without refreshing project in navigator view (F5)

These things will be fixed in the next releases I’m sure.

Two last things I want to say:

• if you don’t have someone on the team who is sufficiently fluent in Java, you’ll have a hard time to implement non-trivial solutions; depends on your or my definition of ‘non-trivial’ of course ;-)
• after working with TOS for some time now, I have the feeling that it can solve nearly any problem that might occur in such a project

During the recent holidays I spent the entire time away from work and with my family. As most of the time when I’m away from work I made a list of things to look at. Wicket was not on that list. I seldom make it at least half way thru that list anyway. It was the same this time. But then I saw this article on TheServerSide about the release of Wicket 1.3. The big amount of comments caught my interest. Suddenly, Wicket was on that list.

Today, I downloaded and installed Wicket, and then looked for documentation and tutorials. Besides some interesting online resources, I found the combination of two books on Wicket the most helpful:

• The first ten available chapters of Wicket in Action (MEAP - Manning Early Access Program) by Martijn Dashorst and Eelco Hillenius, published by Manning Publications Co.
• Enjoying Web Development with Wicket by Ka Iok Kent Tong, published as PDF only, with freely available first three chapters

The first book seems a little more verbose than the second book and covers more background, while the second book (besides being more complete right now) has much more source code examples. They complement each other perfectly in my opinion. So I got them both.

After reading thru the first three freely available chapters of “Enjoying Web Development with Wicket”, I got interested in chapter 6 (Supporting Other Languages). I was really impressed to see how I18N is a first class citizen in Wicket.

I then turned to “Wicket in Action”. Right now it is not completed and contains many errors, but none of this is really a problem. I made it thru the chapters 1-4 and implemented the Cheesr sample application (from chapter 4) along the way.

I really like what I’ve seen so far from Wicket:

• It’s component based and encapsulates the request/response cycle
• Components seem easy to write
• Good internationalisation concept
• Separation from logic and presentation

Right, I’ve barely scratched the surface yet, but Wicket as a web framework looks promising.

Three days after GWT 1.4.60 came out, the issue was reported, approximately at the same time I was experiencing it. I was hoping for a quick fix, but it didn’t come.

Several month later, Google’s Scott Blum wrote in the GWT forum about an updated GWT 1.4 release. Although I read the forum quite regularly, I nearly missed his posting. He talks about the new release fixing the problem, and he also provides a download link for GWT 1.4.61. I’ve downloaded it and upgraded all my application without a problem so far.

Since it fixes a very serious problem, you should upgrade also. Problem is, you will not see the new version on the GWT download page. At least not yet, but I bet you will see it there shortly. In the meantime, just use this link.

Update: It took a little bit longer than I expected, but the GWT Team has just officially released GWT 1.4.61, which takes care of some minor bugs in the previous release of GWT 1.4.60. The two main issues that were addressed are the “operation aborted” startup error on IE and a potential XSS vulnerability in hosted mode.

There are no differences between the 1.4.61 version released on December 12th, 2007 and the 1.4.61 version released on November 3rd, 2007.

Even though small development teams use a version system in many cases, an issue tracking system is used to a lot lesser extend. But I believe that it’s quite as important as having something like Subversion, because it makes the developers life so much easier. I have just experienced it while working in a small team during my current project. And there are solutions out there, that are easy to install and maintain. One (and one of the easiest and best) is Trac: Trac is an integrated software configuration (and project) management system (SCM). It’s an issue tracking system for software development projects with an integrated wiki. Basically, it’s a project management suite which includes a wiki, a bug/issue tracking system, and a source control viewer that accesses a Subversion repository.

Since developers always tend to try out the newest and latest (I’m no exception to this rule, nor do I want to disappoint you), I’ve installed the Trac version currently under development (0.11dev). The integration with the Eclipse development environment also requires the latest development version of the Trac XML-RPC plugin. This is what you should have installed already:

• Eclipse development platform with Mylyn Trac Connector.
• Working Subversion (SVN) installation.
• Python is installed on your system (Trac is written in Python).
• easy_install is available.
• It helps if you have installed an older version of Trac (e.g. 0.10.4) once. If you don’t have any experience with Trac, you should go there and read their documentation.

Now install Trac and the Trac XML-RPC plugin:

• Checkout the latest development sources from Trac: http://svn.edgewall.org/repos/trac/trunk.
• Install/update Trac from the trunk directory: $ python setup.py install.
• Checkout the sources from the Trac XML-RPC plugin: http://trac-hacks.org/svn/xmlrpcplugin.
• Install/update the Trac XML-RPC plugin as decribed here: $ easy_install trunk.
• Edit trac.ini and add (under [components]) tracrpc.* = enabled.
• Start (or restart) Trac, e.g. via tracd.

You can now access and create your Trac tickets from within Eclipse with the help of the Mylyn Trac Connector.

If the application doesn’t load, please click here!

Before I was able to include a GWT application within a post in this WordPress powered blog, I had to create a WordPress plugin that generates the necessary meta tags. GWT applications only work, when those meta tags are present.

The actual calculation of the expression is done on the server with the help of my Java based framework. The expression is sent to the server asynchronously as a JSON data packet. The server logic evaluates the expression and sends back either the result, or an error message. If you want to see an error message, try a division by 0. The response is sent also in the JSON format back to the browser, where the GWT application takes it and displays it without refreshing the whole page.

The server side logic is built with the help of ANTLR and ANTLR Studio for Eclipse. Instead of writing a lexer and parser for evaluation of the expressions myself, I’ve used a grammar to let these tools do it for me. The following screenshot shows ANTLR Studio for Eclipse in action:

If you want to know what ANTLR is, here is a quote from Terence Parr, the primary author of ANTLR. He has been working on translation tools since the late 80s:

ANTLR, ANother Tool for Language Recognition, (formerly PCCTS) is a parser and translator generator tool, akin to the venerable lex/yacc duo, that lets you construct recognizers, compilers, and source-to-source translators from grammatical descriptions containing C++ or Java actions. You can build translators for database formats, graphical data files (e.g., PostScript, AutoCAD), text processing files (e.g., HTML, SGML), etc. ANTLR is designed to handle all of your translation tasks. ANTLR is recommended by the co-inventor of LL(k) parsers and by the inventor of SLR(k) and LALR(k) parser.

Another tool makes generation of GWT clients easier. It’s the GWT Designer from Instantiations. I’m having a few problems with it, but it still helps a lot. See the following screenshot for an impression:

If you’re interested in this example built with GWT, ANTLR, JSON, etc., and you want to look at the source code, just download it from here.

Do you remember the little problem from the Geometry for kids post earlier today? With the calculator, you can verify if the solution is correct: d = sqrt(3)*5.3.

Update: As of GWT 1.4, a new application-loading mechanism has been introduced, that doesn’t require a meta tag in the page header. It’s still supported for legacy applications. But now, the applications HTML code can directly reference the JavaScript file. I’ve changed the example above accordingly.

While this might be an easy problem for grownups, it seemed not so easy for her. She drew a grid model of the cube, connected the opposite vertices, and measured off the length of the resulting diagonal. It seem logical and right for her. When I asked her about the actual angles in a cube, and how they relate to her projection, it became quite clear, that some angles in the drawing weren’t quite what they should have been.

In my opinion, kids have to learn how to ask the right questions, and how to find answers. And then they should explain it to somebody else. As a freshman I earned some extra money by giving private lessons for juniors and seniors. I quickly learned, that I was only able to explain a problem and its solution in depth, when I was able to answer all kinds of questions they were throwing at me. It didn’t have anything to do with knowledge, but with the ability to express it. And that is quite harder. So whenever you want to make sure you truly understand something, talk to someone about it for a couple of minutes, and have her or him ask you questions.

Finally, she was able to find a solution to the problem. I didn’t explain it to her, but I asked her some questions. She had to explain it to me.

First, I looked for help where all the WordPress plugins/meta are listed. None of them seems to solve my problem. To be honest, I only looked at a few, so I really don’t know if I’ve overlooked the one I need. One Meta plugin came quite close to what I want, but it was for description and keywords only. Except that, it would have been perfect. So I took its idea and modified it.

You have to use WordPress’ custom fields for storing the gwt:module meta tags. Just create a new custom field when you create or edit a post. The key should be set to gwt:module, and the value should be the path and name of your GWT module. The plugin then collects all gwt:module meta tags for all posts on the page and puts them in the header section of the page.

In case you want to use this plugin yourself, you can download the WordPress plugin for creating gwt:module meta tags from this web site.

Later today, I will write a post that actually has a GWT application included.

Epsilon is an Emacs clone, but unlike Emacs, which can be extended with Lisp code, Epsilon uses a C-like language called EEL (Epsilon extension language). As you can see from the list of programming languages I’m sufficient familiar with, Lisp isn’t on it, but C is. Although this short enumeration of programming languages isn’t complete, I haven’t used any of the others for a substantial amount of time. It’s important for me, that Epsilon is programmable in a language I’m fluent in.

There’s one exception to my otherwise consistent use of Epsilon. When it comes to Java programming, I’m using Eclipse most of the time. Not always, because some things I still do with Epsilon, but most of the things are a little easier within Eclipse.

During the time I worked with Epsilon, I observed a strange thing: some programmers (even brilliant ones) worked with editors that are not supporting them well with their work. Even when shown alternative editors that would support them much more, they gave up early on learning the features of the new tool. Instead, they spend hours writing some small utility programs for tasks that are possible within minutes for editors like Epsilon. Instead of investing the time in learning a new tool, they spend much more time with fixing the shortcomings of the editors they were used to.

Don’t get me wrong, Epsilon is not a panacea for everything, and I’m gone the minute I find something better. But in the past 10 years, I haven’t.

FATAL ERROR IN TWO-TASK SERVER: error = 12571
ksedmp: internal or fatal error

This error is logged by Oracle in the user dump trace files. After this error has occurred, no more pages can be compiled. From the ACU client software, it looks like the system is locked up. Only a restart of the synformation server software will help temporarily.

Page compilation within synformation is triggered by altering a block or a page template. The error can be easily reproduced by first altering a page template or a global block, directly followed by altering a local block. This almost always has the consequence that the ACU client software locks up. It’s not possible to compile pages from other ACU clients after this error has occurred. The error can be forced also by changing global and local blocks from different ACU clients.

Since such an error hasn’t been observed on other databases, I assume that it’s a problem only for Oracle databases prior to version 10g. Apparently, the error can be prevented if a certain foreign key is dropped. I recommend that everyone who runs synformation on an Oracle database prior to 10g deletes this key. Executing the following statement will fix the problem:

ALTER TABLE "SYN_PAGE_SECTIONS"
DROP CONSTRAINT "FK_PAGE_SECTIONS_BLOCK_ID" CASCADE;

Deleting this key has no side effects on the operation of the system.

I know that error 12571 hints to a network timeout. It seems strange that dropping a foreign key constraint fixes the problem, but I’ve tried hard to find a fix that feels more logical. Everything else I tried did not fix the problem. I’m not really satisfied with the solution, in part because synformation has a heavily normalised data model, and this fix breaks the beauty. I guess I’ve to live with that. Maybe someone else knows something to ease my pain?