Using ADF Logging in a non-ADF project

In a previous post (Starting with ADF 11G Logging), I explained how ADF logging is simple to set up, and how it will enable you to set the logging levels at runtime, without having to restart any server. When I showed this to a colleague of mine, he immedialtely popped the question : “Can’t we use this for all of our java applications, even the ones that don’t use ADF?”. Well, the answer is yes, and it turns out to be very easy. Just add the correct jar to your project and your done.

This blog will demonstrate how to get this working. I use Eclipse Juno to create a small webproject, only containing a servlet that does the logging. In fact I will use the same servlet I used in the previous post.

So I open my Eclipse , and started with a File -> New -> Dynamic Web project. Give it a name, set ‘Dynamic web module version’ to 2.5, click the  ’Add project to an ear’ checkbox and click finish.

Now Eclipse has created a web and ear module for me.

Now right click the web project (ADFLogging), and select New -> Servlet, give it a name, eg. TestServlet, and click finish.

Remove the generated code in the servlet, and copy the code from the servlet ‘ExecuteLogger’ from my previous post (here) and paste it in our new serlvet.

PS. : When you copied the code from my previous blog, don’t forget to set ADFLogger.createADFLogger to our current servlet class name : TestServlet.class.

We will get compile errors on HttpServletRequest,etc… and on the ADFLogger class because they are not defined in the classpath of the project. So we’ll add them in order to get our servlet compiled.  I get the 2 jar’s from a JDeveloper installation I did on my machine. We’ll only add these jar’s in order to get the servlet compiled in Eclipse. We will NOT deploy them, as they are already available on our Weblogic server.

To add the jar’s, right click on the web project, and go to Properties. In the Properties, click on ‘Java Build Path’.

Click on ‘Add External JARs…’ , and go to the directory where you installed your JDeveloper, which in my case is : C:\Oracle\Middleware.

In that directory , get following jar’s from the sub-directory :

\oracle_common\modules\javax.servlet_1.0.0.0_2-5.jar : contains the servlet classes like HttpServletRequest/Response,etc…

\oracle_common\modules\oracle.adf.share.ca_11.1.1\adf-share-base.jar : contains the ADFLogger classes.

Now we see the the following jar’s added :

Click OK and return to the servlet. In the servlet use CTRL-SHIFT-O to import the neccessary classes from the jar’s we just added.

Now all compile errors should be gone.

Generate the ear file as follow : File -> Export -> Ear file

Select the ear project and enter destination of the ear file

When you examine the ear, you will notice that the folder \WEB-INF\lib is empty.

As the servlet and ADFLogger jar is already available on Weblogic, there is no need to deploy it with our application.

Now deploy the ear to the Weblogic and test the servlet with following url. :

http://localhost:7101/ADFLogging/TestServlet

It will generate following output :

To check the logging done by this servlet :

As I used the integrated Weblogic of JDeveloper, I will look for my logs using JDeveloper, but in a production environment,

these logs can be viewed using the enterprise manager of Weblogic. For details, see my previous blog.

In the Oracle Diagnostics Logging configuration, I see my servlet after the deployment. No message level is defined, so it will take “Warning”, as this one is defined as default by the Root Logger

After te execution, I see following log lines in the log analyzer.

So that’s it. So the bottom line is to add the ADFLogger jar to your non-ADF project, and you are ready to go !

Starting with ADF 11G Logging

In software development, logging is an indispensible part of the job. When developing  java programs, Log4j (Apache framework) is probably the most commonly used framework.

But when we are writing Java programs, using the Oracle ADF framework, there is another option : ADF Logger. This logger is integrated in the Weblogic enterprise manager, and gives you the flexibility to adjust your log-levels at runtime. This blog post briefly demonstrates how the ADF logging works, using a servlet that logs at all levels.

The first example is run on a remote Weblogic server. At the end of the post the same example is run within the integrated Weblogic server of JDeveloper.

First we start with viewing the loggers defined in Oracle Enterprise Manager (OEM) before our servlet is deployed :

When we select ‘Log Configuration’ we get the Log Configuration screen, where some loggers are already defined and their loglevels can be configured :

We’ll deploy a servlet that uses the ADF Logger, change the loglevels at runtime, and check the logging to see what happens.

So fire up your JDeveloper and select a new Fusion Web Application (ADF) or download the JDeveloper project from  https://www.dropbox.com/s/mwkjdw8k265iadx/LoggerApp.zip

Then create a servlet like the one below, which is a simple servlet called ‘ExecuteLogger’ that logs a message on all loglevels :

package be.iadvise.loggerapp;

 import java.io.IOException;
 import java.io.PrintWriter;

 import java.util.Calendar;

 import javax.servlet.*;
 import javax.servlet.http.*;

 import oracle.adf.share.logging.ADFLogger;

 public class ExecuteLogger extends HttpServlet {
  private static final String CONTENT_TYPE = "text/html; charset=UTF-8";

 private static ADFLogger _log = ADFLogger.createADFLogger(ExecuteLogger.class);

  public void init(ServletConfig config) throws ServletException {
  super.init(config);
  }

 public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  response.setContentType(CONTENT_TYPE);
  PrintWriter out = response.getWriter();
  out.println("<html>");
  out.println("<head><title>Executing logging with ADFLogging and System.out.println</title></head>");

 Calendar cal = Calendar.getInstance();
  String loggingId = Long.toString(cal.getTimeInMillis());
  out.println("<h1>Executing logging with ADFLogging and System.out.println</h1>");
  out.println("<h2>Used Logging id = "+loggingId+"</h2>");
  out.println("<p>The logging id is different for each request.</br>Use the logging id to search the log messages in the logfiles or EM for this request.");
  out.println("<p>Logger Name in EM = "+_log.getName());

  out.println("<p>****************** START LOGGING ******************");

  out.println("<table >");

 // FINEST
  _log.finest("Loglevel finest : This is a logmessage with the ADFLogger. Logging id = "+loggingId);
  System.out.println("Loglevel finest : This is a logmessage with the System.out.println. Logging id = "+loggingId);
  out.println("<tr><td>FINEST</td><td>Loglevel finest : logMessage written to ADFLogger and System.out.println. Logging id = "+loggingId+"</td></tr>");

  // FINER
  _log.finer("Loglevel finer : This is a logmessage with the ADFLogger. Logging id = "+loggingId);
  System.out.println("Loglevel finer : This is a logmessage with the System.out.println. Logging id = "+loggingId);
  out.println("<tr><td>FINER</td><td>Loglevel finer : logMessage written to ADFLogger and System.out.println. Logging id = "+loggingId+"</td></tr>");

  // FINE
  _log.fine("Loglevel fine : This is a logmessage with the ADFLogger. Logging id = "+loggingId);
  System.out.println("Loglevel fine : This is a logmessage with the System.out.println. Logging id = "+loggingId);
  out.println("<tr><td>FINE</td><td>Loglevel fine : logMessage written to ADFLogger and System.out.println. Logging id = "+loggingId+"</td></tr>");

  // CONFIG
  _log.config("Loglevel config : This is a logmessage with the ADFLogger. Logging id = "+loggingId);
  System.out.println("Loglevel config : This is a logmessage with the System.out.println. Logging id = "+loggingId);
  out.println("<tr><td>CONFIG</td><td>Loglevel config : logMessage written to ADFLogger and System.out.println. Logging id = "+loggingId+"</td></tr>");

  // INFO
  _log.info("Loglevel info : This is a logmessage with the ADFLogger. Logging id = "+loggingId);
  System.out.println("Loglevel info : This is a logmessage with the System.out.println. Logging id = "+loggingId);
  out.println("<tr><td>INFO</td><td>Loglevel info : logMessage written to ADFLogger and System.out.println. Logging id = "+loggingId+"</td></tr>");

  // WARNING
  _log.warning("Loglevel warning : This is a logmessage with the ADFLogger. Logging id = "+loggingId);
  System.out.println("Loglevel warning : This is a logmessage with the System.out.println. Logging id = "+loggingId);
  out.println("<tr><td>WARNING</td><td>Loglevel warning : logMessage written to ADFLogger and System.out.println. Logging id = "+loggingId+"</td></tr>");

  // SEVERE
  _log.severe("Loglevel severe : This is a logmessage with the ADFLogger. Logging id = "+loggingId);
  System.out.println("Loglevel severe : This is a logmessage with the System.out.println. Logging id = "+loggingId);
  out.println("<tr><td>SEVERE</td><td>Loglevel severe : logMessage written to ADFLogger and System.out.println. Logging id = "+loggingId+"</td></tr>");

  out.println("</table>");

  out.println("<p>****************** END LOGGING ******************");

  out.println("<body>");
  out.println("</body></html>");
  out.close();
  }
 }
 

Then, map this servlet in your web.xml as follows :

<servlet>
 <servlet-name>ExecuteLogging</servlet-name>
 <servlet-class>be.iadvise.loggerapp.ExecuteLogger</servlet-class>
 </servlet>
 <servlet-mapping>
 <servlet-name>ExecuteLogging</servlet-name>
 <url-pattern>/executeLogging</url-pattern>
 </servlet-mapping>

The line

private static ADFLogger _log = ADFLogger.createADFLogger(ExecuteLogger.class);

will create an entry in the ADF logging panel of OEM  for the class ‘be.iadvise.loggerapp.ExecuteLogger’ during the first execution of our servlet.

So generate the ear file (in JDeveloper : Application -> Deploy -> your application) , and deploy to an ear , and deploy the ear to your remote Weblogic.

Then, execute the servlet by entering following url in a browser http://server:port/appname/executeLogger

We will receive the following output where the logging id is a unique id for every request (this will help us find the log info logged for every run) :

and in our log configuration screen, the logger for our servlet is added automatically with level WARNING :

When we look to the logging itself, by selecting the following :

We see that our servlet has logged 2 lines  : level WARNING and ERROR, as the logger was default created with level “warning”.

(We look in the log files for the id generated by the servlet to get our 2 lines)

Now let’s update our log level to TRACE (finest), press apply, confirm the update, execute the servlet again , and see what happens to our logging :

confirm the update :

execute the servlet again (it generates a new logging id)

look for the generated logging :

As we have set the loglevel to trace (finest), which is the lowest level, we see all the generated loglines.

Remark : When we undeploy the application, the logger will remain visible in the log configuration screen until the managed server is restarted.

Using the integrated Weblogic server in JDeveloper

This screen shot shows you how get to the log configuration and logging screen in JDeveloper :

After executing the servlet locally, the Oracle Diagnostic Logging will show you the following :

and the analyze log :

then we change the log level :

and execute the servlet again and watch the output :

That’s it !!!

The big advantage of ADFLogging is the update of the loglevel at runtime, so whenever something seems to be going wrong, just set the loglevel to e.g. TRACE and check the logfiles. When the problem is solved reset it to WARNING or ERROR. And this without having to restart your application.

Also, being able to view and search the logfiles using the EM increases the userfriendlyness of this system. You don’t have to access the files directly on the system anymore.