Talend Open Studio and NullPointerException in tMap


The tMap component in Talend Open Studio is a very powerfull component, however is common to encounter an exception message like this:

Exception in component tMap_1 java.lang.NullPointerException
at test.test_0_1.Test.tMysqlInput_1Process(Test.java:2502)
at test.test_0_1.Test.runJobInTOS(Test.java:2793)
at test.test_0_1.Test.main(Test.java:2705)

The exception message is shown in the picture:

Data Mining techniques on Twitter to discover user sentiment

Twitter provides a comprehensive web serice API which can be used to retrive its data. At the university of Waikato some researchers used Weka (a popular Data Mining Open Source tool) to process Twitter real time data. Their objective was to analyze users's sentiment, in other words if each single post contained a positive or negative feeling.

For example, a message like "Of course I will" has a positive meaning, while "It's wrong" contains a negative one. And it's possible to consider emoticons like :-) or :-| as well.

Enable access from remote hosts in Pentaho


Pentaho Business Intelligence Suite listens by default on localhost port 8080.

To allow access from remote clients other than localhost you need to edit the configuration file <pentaho-home>\tomcat\webapps\pentaho\WEB-INF\web.xml replacing the default string


with something like this

Customize Pentaho home page, logo and login form


Pentaho Business Intelligence Platform is written in Java EE and is Open Source (Comunity Edition), this give you a lot of flexibility if you know how to program in Java. You can apply modifications on the source code as long as you accomplish the license terms.

Before proceed with this tutorial you must have at least a basic background in HTML and JSP.


Customize home page

In Pentaho BI Suite version 3.8.0 the default home page is like this.

Pentaho home page to be customized


Import Mondrian FoodMart database in Oracle

Mondrian, the Open Source OLAP engine, contains a sample database named FoodMart, which is quite usefull for data warehousing prouposes. This archive contains all you need to import FoodMart database in Oracle (if you prefer you can download the Mondrian's one, add the missing libraries and JDBC drivers).

To load FoodMart data warehouse in Oracle:

Creating new Documents with Pentaho Design Studio


To create and deploy new documents in Pentaho Business Intelligence Suite you can use the web interface directly. The web interface is usefull when you have simple reports or simple analysis or to let the final user create them. Some external tools, like Pentaho Report Designer or Mondrian Schema Workbench can publish docuements directly into Pentaho's web platform to achive more control on document definition.