JDeveloper 11g: Using assert() for testing and debugging

Assertions are a very useful feature for testing and debugging, but are rather neglected. Instead of using loggers to provide continuously diagnostic messages in critical programme  flow points, or even worse if- else - System.out.println() constructs, assert statements can only be enabled only when necessary. Thus, you avoid wasting valuable resources. In addition, you do not need to add any jar libraries to your IDE  project, or application server to use it. In order to use assert, you need to  pass the -ea argument, call a non void java method and check a Boolean  condition. For instance: assert(Month < 13). Nonetheless, you can not  use an assert statement to check the values passed to public methods. Consider for example the following code snippet, from an business components, employees entity object:
              
protected void doDML(int operation, TransactionEvent e) {
                if (operation == DML_UPDATE) {
    ...
               histStartDate = row.getEndDate();
              /*Check whether end date equals current date*/
              /*if (histStartDate.equals(new Date(Date.getCurrentDate()))){
                  System.out.println("End date equals current date!");
                  }*/
               assert(histStartDate.equals(new Date(Date.getCurrentDate() ) )) :
                          "End date equals current date! ";

Another trivial example from an ejb client follows:

public class PlaceBidClient {
    public static void main(String [] args) {
...
                     Bid bid = placeBid.addBid("Lila",  Long.valueOf(100),  2001.50);
                     System.out.println("Bid Successful, BidId Received is:" + bid.getBidId());
                     assert(bid.getBidId() == 502):"BidId Received is "+bid.getBidId();
  }
}
Finally, when run, the log output reads:

-javaagent:C:\Oracle\Middleware\jdev_11gR1\jdeveloper\..\modules\org.eclipse.persistence_1.0.0.0_2-0.jar -Duser.language=en -Duser.country=US -ea actionbazaar.buslogic.client.PlaceBidClient

Exception in thread "main" java.lang.AssertionError: BidId Received is 393
    at actionbazaar.buslogic.client.PlaceBidClient.main(PlaceBidClient.java:24)Bid Successful, BidId Received is:393

A free site for sports funs: http://www.woop.gr/

This is a new free online Greek sports channel covering both national and international soccer, basketball matches, motorcycle racing events and so on. Since Eurosport channel now asks for subscription and payments, this could be an interesting alternative, in case your spouse insists on watching that boring soap opera. Most text is in Greek, but you can find your way around. Try clicking on "Live" links, in order to find something interesting to watch. So, this is it: http://www.woop.gr/
Finally, if you would like to try other online tv channels there is http://2onlinetv.com.

JDeveloper 11g: Using Log4j in ADF view object

Just like the entity object instance, covered here, the process for an ADF view object, goes like this. First, you add the library as shown in the image on your left hand side. Second, you create a log4j.properties file in:

C:\...\Model\src

 similar to the following example:


# Set root logger level to INFO and its only appender to ConsoleOut.
log4j.rootLogger=INFO, ConsoleOut


# ConsoleOut is set to be a ConsoleAppender.
log4j.appender.ConsoleOut=org.apache.log4j.ConsoleAppender


# ConsoleOut uses PatternLayout.
log4j.appender.ConsoleOut.layout=org.apache.log4j.PatternLayout
log4j.appender.ConsoleOut.layout.ConversionPattern=%-5p: [%d] %c{1} - %m%n


log4j.logger.org.apache.jsp=DEBUG
#Addon for
com.sun.faces.level=FINE






Third, if you want to use logging in several view objects, you need to edit your view object super class code like that:

package tuhra.model.framework;

import oracle.jbo.server.ViewRowImpl;

import org.apache.log4j.Logger;

public class TuhraViewRowImpl extends ViewRowImpl {
  protected Logger logger = Logger.getLogger(this.getClass());
}

and your view object code like that:

public class AllEmployeesRowImpl extends TuhraViewRowImpl implements AllEmployeesRow {...
     public void defineDefaultImage(Number newDefaultImageId){
 ...
                      if (logger.isDebugEnabled())
                         logger.debug("Default Image has been defined!");

 }
}

Next your diagnostic message appears in the log output window:

INFO : [2010-09-25 11:55:18,739] AllEmployeesRowImpl - DefaultImage has been defined!
Finally, if you need more tips about appenders:
http://www.mobilefish.com/developer/log4j/log4j_quickguide_appenders.html

The full source code is available on line:
http://code.google.com/p/nickaiva-blogspot/downloads/list

and is given without any guarantee of support whatsoever.

Estimate the taxi fare for your routes in Athens, Greece

Many people and mostly tourists, protest about the exorbitant fares paid to taxi drivers, especially in Athens, in greater Attica and other areas. In order to help the passengers in estimating beforehand their fare, I shall publish about  a Greek site, that is it has some text in Greek, I am afraid! So, you can visit the following blog url: http://www.zee.gr/taxi/ and click on taxi estimator to enter your starting point and destination, just by clicking on the map!

JDeveloper 11g:Using Log4j in an ADF application module

This is another concise instance for using Log4j in  an ADF application module, that is  in a  model project. The steps are quite similar:
starting with adding the log4j library, as shown in the image on your left hand side.
Next,  you need to create a log4j.properties file, within:

C:\...\Model\src

just  like the following:


# Set root logger level to INFO and its only appender to ConsoleOut.
log4j.rootLogger=INFO, ConsoleOut
# ConsoleOut is set to be a ConsoleAppender.
log4j.appender.ConsoleOut=org.apache.log4j.ConsoleAppender
# ConsoleOut uses PatternLayout.
log4j.appender.ConsoleOut.layout=org.apache.log4j.PatternLayout
log4j.appender.ConsoleOut.layout.ConversionPattern=%-5p: [%d] %c{1} - %m%n
log4j.logger.org.apache.jsp=DEBUG
#Addon for
com.sun.faces.level=FINE


Third, you need to edit your code just like that:

...

import org.apache.log4j.Logger;

...

public class TuhraServiceImpl extends TuhraApplicationModuleImpl implements TuhraService {

  private Logger logger = Logger.getLogger(this.getClass());

...

public void createNewImageForEmployee(Number employeeId, String imageName){

...
   if (logger.isDebugEnabled())
      logger.debug("New image has been created!");   

    }

}


Finally,  you should see your logger message appear in the log output window;


INFO : [2010-09-16 10:26:16,517] TuhraServiceImpl - New image has been created!

Would you like to refactor?

Moreover, you could move the code line below:


private Logger logger = Logger.getLogger(this.getClass());


 to the super class:


package tuhra.model.framework;
 
import oracle.jbo.server.ApplicationModuleImpl;
import org.apache.log4j.Logger;

public class TuhraApplicationModuleImpl extends ApplicationModuleImpl {

  protected Logger logger = Logger.getLogger(this.getClass().getName());

}


Once more, your custom  logger message should appear in the log output :


INFO : [2010-09-16 15:20:02,247] TuhraServiceImpl - New image has been created!

Finally, if you need more tips about appenders:
http://www.mobilefish.com/developer/log4j/log4j_quickguide_appenders.html  
https://logging.apache.org/log4j/2.x/

International Herald Tribune edition is now available in Greece, by Kathimerini

For those interested in learning news from the inside, about Greece: 
http://www.ekathimerini.com/

Comments on Oracle SOA Suite 11g R1 Developer's Guide, by Matt Wright and Antony Reynolds

On the bright side, the text is well written in British English,  and neatly organized as well. It is based on the successful recipe of the previous book about 10g SOA and it's  divided in three parts: the first is a short introduction to the Oracle SOA Suite and its various components, and will give you an fast-paced, but limited hands-on, introduction to each of the key components. The second section provides a brief best-practice guide to applying the various components of the SOA Suite to implement a real-world SOA-based solution; it illustrates this through the development of an auction site (oBay) whose source code is actually missing! The final section covers other subjects, such as the packaging, deployment, testing, security, and administration of SOA applications.
On the dark side, some hands on practice although realistic, require a permanent connection to the internet, since currency rates conversion and stock exchange quotes are necessary for testing your BPEL process. These are not always available (I got many "Server too busy" messages) and this might hinder you from completing your practice correctly. Besides, the source code offered publicly, contains only the final solution, but no solutions for the intermediate steps, nor sample inputs for testing, i.e. EUR for the euro currency. Furthermore, the code for oBay application is actually missing and so is its installation guide, mentioned in the text. I think the approach about self contented practice taken by the other competitor: Getting started with Oracle SOA 11g suite is by far better. In fact, its step by step instructions are more exact and easier to follow.
In summary, the book offers a sound theoretical basis better than its competitor, but it is so much weaker in guidance  and in hands on practice. Moreover, some chapters, such as 18 about business rules, are rather purely descriptive and hence difficult to follow. Whether you need such a book which resembles the free on line Oracle Fusion SOA developer guide manual, it is up to you. It targets developers or  technical architects who work in the SOA domain. Of course there are some prerequisites, I quote: "You need basic understanding of the concepts of SOA, as well as some of the key standards in this field, including web services (SOAP, WSDL), XML Schemas, and XSLT (and XPath)". Finally, you need a fast computer, preferably with more than 4GB of memory, to setup the SOA suite.

JDeveloper 11g:Using Log4j in ADF business components projects

In case you prefer using  ADF business components in your Model project, the procedure for using log4j logging is almost identical with the EJB way. You might also read an example on using logging within an ADF application module as well.
First, you need to add the library, by double clicking your Model project, as you can see on your left hand side.
Second, you need to create a log4j.properties file within:
C:\...\Model\src

just  like the following:


# Set root logger level to INFO and its only appender to ConsoleOut.
log4j.rootLogger=INFO, ConsoleOut

# ConsoleOut is set to be a ConsoleAppender.
log4j.appender.ConsoleOut=org.apache.log4j.ConsoleAppender

# ConsoleOut uses PatternLayout.
log4j.appender.ConsoleOut.layout=org.apache.log4j.PatternLayout
log4j.appender.ConsoleOut.layout.ConversionPattern=%-5p: [%d] %c{1} - %m%n

log4j.logger.org.apache.jsp=DEBUG
#Addon for
com.sun.faces.level=FINE


Third, you edit your entity object code like that:
...
import org.apache.log4j.Logger;



public class ImagesImpl extends TuhraEntityImpl {
...

    private Logger logger = Logger.getLogger(this.getClass());
  ...

    private void adjustImageUsages(RowSet newImageUsagesBeforePost) {
   ...
      if (logger.isDebugEnabled())
             logger.debug("ImageUsages has been adjusted");
        }
...
}

Finally the message you created appears in the log output window:
INFO : [2010-09-12 09:56:32,593] ImagesImpl - ImageUsages has been adjusted

Would you like to refactor?

Furthermore, if you use logging within multiple entity objects, you could move the declaration code line:

private Logger logger = Logger.getLogger(this.getClass());

to the super class:

package tuhra.model.framework;

import oracle.jbo.server.EntityImpl;
import org.apache.log4j.Logger;

public class TuhraEntityImpl extends EntityImpl {
  protected Logger logger = Logger.getLogger(this.getClass());
}


Upon commit, the logger output appears once more:

INFO : [2010-09-16 10:28:07,288] ImagesImpl - ImageUsages has been adjusted

For dynamic changes of logging levels, one can consult for example:
dynamically-changing-log-level-with-weblogic-log4j-jmx-and-wlst/

Finally, if you need more tips about appenders:
http://www.mobilefish.com/developer/log4j/log4j_quickguide_appenders.html
https://logging.apache.org/log4j/2.x/

JDeveloper 11g:Using Log4j in a JSF backing bean

Another example which might prove useful to JSF or ADF developers,  is logging within a backing bean.
First, you need to add the Log4j.jar by double clicking the ViewController project. You can see the library window on your left handside, showind the jar already added. Note that you can use logging via log4j in combination with ADFLogger, that is if you are using ADF, or even without it.

Second, you need to create the log4j.properties file in ViewController/src. Another  log4j.properties sample file is given here, for your convenience:


# Set root logger level to INFO and its only appender to ConsoleOut.
log4j.rootLogger=INFO, ConsoleOut

# ConsoleOut is set to be a ConsoleAppender.
log4j.appender.ConsoleOut=org.apache.log4j.ConsoleAppender

# ConsoleOut uses PatternLayout.
log4j.appender.ConsoleOut.layout=org.apache.log4j.PatternLayout
log4j.appender.ConsoleOut.layout.ConversionPattern=%-5p: [%d] %c{1} - %m%n
log4j.logger.org.apache.jsp=DEBUG
#Addon for
com.sun.faces.level=FINE


Third, you need to code! The example bean code follows:
...
import org.apache.log4j.Logger;
...
public class ImageUploadBean extends TuhraBackingBean implements Serializable {
  private Logger logger = Logger.getLogger(this.getClass());
  ...
 private void insertRows() {
...
    if (logger.isDebugEnabled())
       logger.debug("Succeeded in adding new image!");
    }
}

Finally, your message appears in the log window:

INFO : [2010-09-11 21:47:52,005] ImageUploadBean - Succeeded in adding new image!

Would you like to refactor?

Furthermore, if you use logging in several beans, you could move the declaration code line:

private Logger logger = Logger.getLogger(this.getClass());
 

to the super class TuhraBackingBean:

package tuhra.view.framework;

import oracle.adf.model.BindingContext;

import oracle.binding.BindingContainer;

import org.apache.log4j.Logger;

/**the purpose of this framework class is to
access the commonly used properties.
 */
public abstract class TuhraBackingBean {
   
    protected Logger logger = Logger.getLogger(this.getClass());
 
  /**the purpose of this framework method is to
  access the bindings programmatically.
   */
    public BindingContainer getBindings() {
        return BindingContext.getCurrent().getCurrentBindingsEntry();
    }
}
Then the log outputs once more:
INFO : [2010-09-16 09:46:37,767] TuhraServiceImpl - New image has been created!
INFO : [2010-09-16 09:46:37,767] ImageUploadBean - Succeeded in adding new image!

where the first info message comes from the application module code (this could be another example I suppose!), while the second from the aforementioned backing bean. You could follow more or less the same steps for JDeveloper 10g too.
Finally, if you need more tips about appenders:
http://www.mobilefish.com/developer/log4j/log4j_quickguide_appenders.html

https://logging.apache.org/log4j/2.x/