The Dev Donkey Blog

I posted this message today on the olap4j mailing list. In the interest of reaching a broader audience, I will copy it here as well.

Cheers!

Dear olap4j community members,

As we previously discussed on this mailing list, we are planning to make the final push towards a 1.0 specification. In order to perform those much needed changes and still maintain compatibility as much as possible, the olap4j team proposes the following transition plan.

• 4th week of July - Release of olap4j 0.9.8
  A first initial release, coded 0.9.8, will be performed during the days to come. This release is mostly a wrap-up of the unofficial releases we have put in the Maven repository. Notable changes include compatibility with SAP BW, contextual drill-through for the Query Model, along with various other compatibility fixes.
• Month of August
  During the month of August, the olap4j community will have a chance to comment the proposed changes to the 1.0 final draft. We will provide an updated functional specification document as well as a complete list of the changes that will be required. Should you judge that some items are still missing, or that some should be modified or removed altogether, you are encouraged to let us know. The mailing list is the best place to hold those discussions, or you can also use our forums.
• September 1st - Release of 0.9.9
  September 1st is the date that marks the end of our discussions. After that, all the changes that we agreed upon will be implemented in the API, as well as the Mondrian and XML/A implementations of the driver. The 0.9.9 release will include those changes, but will still maintain retro-compatibility. Some API calls will be marked for deprecation, new ones will be present as well. The 0.9.9 release will be the last available before 1.0. Everything that is marked for deprecation will be removed as of 1.0, so users will have a chance to convert their code base progressively.
• October 31st - Release of 1.0
  We are planning to release olap4j 1.0 on October 31st. All methods that have been marked as deprecated, whether by the 0.9.9 release or any other previous 0.X release will be removed.

A proposed updated functional specification document, as well as a detailed list of API changes will be sent in the following days, right after the 0.9.8 release. We strongly encourage the users of olap4j to express any concerns or ideas that might arise.

Sincerely yours

Luc Boudreau, for the olap4j development team

Last week we worked on a guerilla-marketing video for Wabit. I’ll let you be the judge of that.

Last week I launched a spin off of the olap4j parser. Mdx4j wraps olap4j’s MDX parser and makes it available to code, without the need of an olap connection.

Why?

Although olap4j contains a SPI parser, we don’t want to promote any particular MDX syntax. I therefore packaged it as a separate project so that everyone can have a piece of the pie!

final String query =
“SELECT{} ON COLUMNS FROM CUBE”;

final MdxParser parser =
Mdx4jParserFactory.createMdxParser();

final ParseTreeNode tree =
parser.parseSelect(query);

http://code.google.com/p/mdx4j/

A colleague of mine once asked me if I knew a program that can connect to almost all relational databases and offers MsAccess like features to build queries. Sure thing says I. Wabit.

So he downloads it and installs it in 5 minutes. It’s free and open source. No hassle. He then creates his connections and manages to do everything he needs to fulfil his duties as a business analyst. Pretty kewl story, heh? Short too. But that’s a good sign because as a developer on this project, I can confirm first hand that this is exactly what we aimed for. Making business intelligence easy and painless.

The Wabit is more than that. It’s also an OLAP data warehouse browsing and reporting tool. It creates charts in 10 seconds and features a template engine for easy corporate branding. Version 1.0 will feature a server repository for multi-user collaboration and incremental saves, scheduling and fine grained security. The enterprise server is not open sourced though, but the Wabit client is a fully featured platform. You can still save all your queries and reports as an XML file for easy import and export and share it with your fellow co-workers.

The Wabit approaches 1.0 now. We need to reinforce the community around it and we need more feedback. The Wabit works on all platforms with a Java JVM, so whatever your background is, I’m sure that we can make good use of your comments or contributions. You are a GUI designer or a BI consultant or even just the regular Java developer, we have need of your help.

Wabit on Google Code
Wabit homepage

(more…)

During my monthly checkup of this blog analytics data (thank you Google Analytics), I discovered a new trend. More and more, people are searching for information on olap4j’s compatibility.Here are the interesting keywords used and the number of occurrences for the last month.

• “olap4j ruby” - 28 occurrences
• “olap4j oracle” - 3 occurrences

Oracle; I can understand. Olap4j is picking up momentum and is more widely adopted. We support both Microsoft Analysis Services and Mondrian via XMLA. Oracle does have an XMLA server, Hyperion Essbase, although we never tested it with olap4j. If one of you reading this post happens to be a Oracle wizard, please contact us so we can have a chat. The more OLAP servers we support the better.Ruby; now that’s intriguing. Ruby can run in a JVM thanks to the JRuby project. Would olap4j work well with JRuby? probably. Are there are any OLAP API for Ruby? Google says no. Digging further in the analytics data didn’t reveal to me the actual intent of those who are searching for “olap4j ruby” keywords. What a mystery… I therefore send out there a general call to anyone interested in using olap4j inside JRuby, for we might have common interests.

Browsing my Google Analytics statistics, I realized there is a lot of people out there that are searching for ways to connect Microsoft SQL Server with olap4j.

Here is a nice example.
// We must use the XMLA driver.
Class.forName("org.olap4j.driver.xmla.XmlaOlap4jDriver");

// This code is for Java 5. With Java 6, you can directly
// unwrap the underlying connection with the .unwrap() call.
OlapConnection connection =
(OlapConnection) DriverManager.getConnection(

// This is the SQL Server service end point.
"jdbc:xmla:Server=http://example.com/olap/msmdpump.dll"

// Tells the XMLA driver to use a SOAP request cache layer.
// We will use an in-memory static cache.
+ ";Cache=org.olap4j.driver.xmla.cache.XmlaOlap4jNamedMemoryCache"

// Sets the cache name to use. This allows cross-connection
// cache sharing. Don't give the driver a cache name and it
// disables sharing.
+ ";Cache.Name=MyNiftyConnection"

// Some cache performance tweaks.
// Look at the javadoc for details.
+ ";Cache.Mode=LFU;Cache.Timeout=600;Cache.Size=100",

// XMLA is over HTTP, so BASIC authentication is used.
"username",
"password" );

// We can execute a query. MDX of course.
CellSet set = connection.createStatement().executeOlapQuery(
"SELECT {} ON COLUMNS FROM CUBE");

Update : Some useful links

• How to: Install Analysis Services by Using Setup
• SSAS Clients Architecture
• Olap4j latest builds

I’ve been working for a month now on some enhancements to the Olap4j project to make it more powerful and compatible. The good news is, I succeeded. The previous version, 0.9.5, lacked some basic functionalities which you would expect from a production ready XML/A driver.

For one, it’s HTTP proxy didn’t support cookies. his was a big problem since the myriad of requests required to populate Olap4j’s meta data objects each created a new user session on the web service back-end. This was a no-no, but now it’s fixed and kicking ass.

I also worked on a SOAP query cache. This is was a big piece of software engineering, since I’m not used to thread safe coding. Thread safe thignys are usually in the lower levels of BI application servers and those issues are tackled from the start. Thanks to Java’s java.util.concurrent package, this was a breeze.

Those changes are not part of any release nor in the SVN yet. I’m still waiting for peer review before the whole commit, but for people eager to see what it looks like, I’ve created a neat little package for y’all.

Now I can move back to my next release of the University of Montreal’s Pentaho platform… all work and no play makes Luc a dull boy.

Cheers !