Servlet 3.0

Application level log4j.xml and logging in JBoss AS7

Hi,

Log4j or any logging framework is very useful entity of any enterprise application, So that we can have a separate Application level logging using our own version of log4j.jar or any other logger framework version.

In this demonstration we will see how to use the log4j logging inside our Web Application, with it’s own version of “log4j.xml” file. We will also talk about the following points:

In this example we will mainly focus on following points

Point-1). How to use the “log4j.xml” which is placed inside “${YOUR_WAR}/WEB-INF/classes” directory.

Point-2). How to avoid using the JBoss provided logging framework or How to exclude the “org.apache.log4j” module provided by JBoss with the help of “${YOUR_WAR}/META-INF/jboss-deployment-structure.xml” file.

Point-3). Where to place your own version of “log4j.jar” file inside your WAR file. “${YOUR_WAR}/WEB-INF/lib”

Point-4). The Source code of this Demo can be downloaded from the following link (Git Repository):
https://github.com/jaysensharma/MiddlewareMagicDemos/tree/master/ApplicationLevelLog4jDemo

Another Demo (uploaded on 26 Nov 2012) at EAR level.
https://github.com/jaysensharma/MiddlewareMagicDemos/tree/master/EAR_Level_Log4jDemo

Developing WAR with it’s own logging

Step-1). Here we are using JBoss AS7.1 Final release latest build “jboss-as-7.1.0.Final” which can be downloaded from the following link: http://www.jboss.org/jbossas/downloads

Step-2). Create a directory with the name “src” somewhere in your file system like “/home/userone/ApplicationLevelLog4jDemo/”. Inside the “src” directory we are going to place our all source code and xml files for development.

Step-3). Write a simple “index.jsp” file inside “/home/userone/ApplicationLevelLog4jDemo/src” as following:

<html>
<head>
<title>Application Level Log4j Demo In JBoss AS7</title>
</head>
<body>

      <form action="TestServlet" method="Get">
           Choose Log Level : 
                           <select name="logLevel">
                              <option>TRACE</option>
                              <option>DEBUG</option>
                              <option>WARN</option>
                              <option selected="true">INFO</option>
                           </select>
                           <BR>
           Enter Mesage to be logged: <input type="textarea" name="logMessage"/> <BR>
           <input type="submit" name="submit" value="log the message"/> 
      </form>
      
</body>
</html>

Step-4). Now we will write a simple Servlet based on Servlet3.0 specification with name “TestServlet.java” inside “/home/userone/ApplicationLevelLog4jDemo/src” as following

package servlets;
import java.io.IOException;
import java.io.PrintWriter;

//servlet-api
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

//log4j
import org.apache.log4j.Logger;

@WebServlet(value="/TestServlet")
public class TestServlet extends HttpServlet 
  {
	private static final long serialVersionUID = 1L;
        private static Logger logger = null;

        public void init() throws ServletException {
         logger= Logger.getLogger(TestServlet.class);   
        }

	public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			PrintWriter out=response.getWriter();
                        String logLevel=request.getParameter("logLevel");
                        String logMessage=request.getParameter("logMessage");
                        out.println("<html><head><title>Log4j Logging Demo</title></head><body>");
                        if(logLevel.equals("TRACE"))
                           {
                             out.println("["+logLevel+"] "+logMessage+" (logged inside log file).");
                             logger.trace(logMessage);
                           }
                        if(logLevel.equals("DEBUG"))
                           {
                             out.println("["+logLevel+"] "+logMessage+" (logged inside log file).");
                             logger.debug(logMessage);
                           }
                        if(logLevel.equals("INFO"))
                           {
                             out.println("["+logLevel+"] "+logMessage+" (logged inside log file).");
                             logger.info(logMessage);
                           }
                        if(logLevel.equals("WARN"))
                           {
                             out.println("["+logLevel+"] "+logMessage+" (logged inside log file).");
                             logger.warn(logMessage);
                           }

                        out.println("<BR><BR><a href="index.jsp"> Want a different logging level? </a></body></html>");
		     } 
                 catch (Exception e) 
                     {
			e.printStackTrace();
		     }
	}
}

Step-5). The most important part, We will need to write the following kind of “log4j.xml” file inside “/home/userone/ApplicationLevelLog4jDemo/src” as following :

NOTE: We need to just make sure that once the application is build this file should be present inside the ${WAR_NAME}/WEB-INF/classes directory.

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
  <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
     <appender name="AppLogAppender" class="org.apache.log4j.DailyRollingFileAppender">
         <param name="DatePattern" value="'.'yyyy-MM-dd"/>
	 <param name="File" value="${jboss.server.log.dir}/MyAppLogsFile.log" />
	 <param name="Append" value="false"/>
         <layout class="org.apache.log4j.PatternLayout">
	     <param name="ConversionPattern" value="%d [%t] %p - %m%n"/>
	 </layout>
     </appender>

     <!-- The "category" represents the package names of your Application APIs which we want to log -->
     <category name="servlets">
         <priority value="TRACE"/>
     </category>

     <root>
         <priority value ="TRACE"/>
         <appender-ref ref="AppLogAppender"/>
     </root>
 </log4j:configuration>

Step-6). Download and place the desired version of log4j jar (like “log4j-1.2.16.jar”) inside the “/home/userone/ApplicationLevelLog4jDemo/src”. So that after building the application this jar will be available inside the “${WAR_NAME}/WEB-INF/lib” directory.

Step-7). Now the most important part, In order to avoid using JBoss provided logging APIs, we need to place the following kind of “jboss-deployment-structure.xml” file inside “/home/userone/ApplicationLevelLog4jDemo/src” so that we can exclude the jboss logging APIs for our application and our application can use it’s own version of logging APIs.

NOTE: after building the WAR file make sure that the “jboss-deployment-structure.xml” is present inside the “META-INF” directory of your WAR file. Example: ${WAR_NAME}/META-INF/jboss-deployment-structure.xml

<?xml version="1.0" encoding="UTF-8"?>
<jboss-deployment-structure>
  <deployment>
    <exclusions>
        <module name="org.apache.log4j" />
    </exclusions>
  </deployment>
</jboss-deployment-structure>

NOTE: If you are using JBossAS 7.1.2 then In order to avoid this ClassCastException you will need to include the following System property in your JBoss -Dorg.jboss.as.logging.per-deployment=false
If you are using JBoss AS7.1.2 and not using the above mentioned “jboss-deployment-structure” file then you will see the following kind of exception at the time of deployment of your WAR:

18:05:41,507 ERROR [stderr] (MSC service thread 1-3) log4j:ERROR Could not create an Appender. Reported error follows.
18:05:41,509 ERROR [stderr] (MSC service thread 1-3) java.lang.ClassCastException: org.apache.log4j.DailyRollingFileAppender cannot be cast to org.apache.log4j.Appender
18:05:41,509 ERROR [stderr] (MSC service thread 1-3) 	at org.apache.log4j.xml.DOMConfigurator.parseAppender(DOMConfigurator.java:248)
18:05:41,510 ERROR [stderr] (MSC service thread 1-3) 	at org.apache.log4j.xml.DOMConfigurator.findAppenderByName(DOMConfigurator.java:176)
18:05:41,510 ERROR [stderr] (MSC service thread 1-3) 	at org.apache.log4j.xml.DOMConfigurator.findAppenderByReference(DOMConfigurator.java:191)
18:05:41,510 ERROR [stderr] (MSC service thread 1-3) 	at org.apache.log4j.xml.DOMConfigurator.parseChildrenOfLoggerElement(DOMConfigurator.java:523)
18:05:41,510 ERROR [stderr] (MSC service thread 1-3) 	at org.apache.log4j.xml.DOMConfigurator.parseRoot(DOMConfigurator.java:492)
18:05:41,511 ERROR [stderr] (MSC service thread 1-3) 	at org.apache.log4j.xml.DOMConfigurator.parse(DOMConfigurator.java:1001)
18:05:41,511 ERROR [stderr] (MSC service thread 1-3) 	at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:867)
18:05:41,511 ERROR [stderr] (MSC service thread 1-3) 	at org.apache.log4j.xml.DOMConfigurator.doConfigure(DOMConfigurator.java:794)
18:05:41,512 ERROR [stderr] (MSC service thread 1-3) 	at org.jboss.as.logging.LoggingConfigurationProcessor.deploy(LoggingConfigurationProcessor.java:111)
18:05:41,512 ERROR [stderr] (MSC service thread 1-3) 	at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:116)
18:05:41,513 ERROR [stderr] (MSC service thread 1-3) 	at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1811)
18:05:41,513 ERROR [stderr] (MSC service thread 1-3) 	at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1746)
18:05:41,513 ERROR [stderr] (MSC service thread 1-3) 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
18:05:41,514 ERROR [stderr] (MSC service thread 1-3) 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
18:05:41,514 ERROR [stderr] (MSC service thread 1-3) 	at java.lang.Thread.run(Thread.java:722)

Step-8). Now in order to build and deploy the above application we will write a very simple ant build script “build.xml” inside “/home/userone/jboss-as-7.1.0.Final/standalone/TESTING/ApplicationLevelLog4jDemo” as following:

<project name="Log4j_Basic_Demo" default="deploy">
<property name="jboss.home" value="/home/userone/jboss-as-7.1.0.Final" />
<property name="jboss.module.dir" value="${jboss.home}/modules" />
<property name="basedir" value="." />
<property name="tmp.dir" value="tmp" />
<property name="output.dir" value="build" />
<property name="src.dir" value="src" />
<property name="war.name" value="Log4jDemo.war" />
 
        <path id="jboss.classpath">
             <fileset dir="${jboss.module.dir}">
                 <include name="**/*.jar"/>
             </fileset>
        </path>
 
        <target name="init">
           <delete dir="${output.dir}" />
           <mkdir dir="${output.dir}" />
           <delete dir="${tmp.dir}" />
           <mkdir dir="${tmp.dir}" />
           <mkdir dir="${tmp.dir}/WEB-INF/lib"/>
           <mkdir dir="${tmp.dir}/WEB-INF/classes"/>
           <mkdir dir="${tmp.dir}/WEB-INF/META-INF"/>
           <mkdir dir="${tmp.dir}/META-INF"/>
        </target>
 
        <target name="build" depends="init">
           <javac srcdir="${src.dir}" destdir="${tmp.dir}/WEB-INF/classes"  includes="*.java" classpathref="jboss.classpath" />
           <copy todir="${tmp.dir}/WEB-INF/classes">
                <fileset dir="${src.dir}" includes="**/*.java"/>
           </copy>
           <copy file="${src.dir}/index.jsp" tofile="${tmp.dir}/index.jsp"/>   

           <!-- Make sure to place the "log4j.xml" file inside ${WAR_NAME}/WEB-INF/classes  directory--> 
           <copy file="${src.dir}/log4j.xml" todir="${tmp.dir}/WEB-INF/classes"/>

           <!-- Make sure to place the "log4j-1.2.16.jar" file inside ${WAR_NAME}/WEB-INF/lib  directory--> 
           <copy file="${src.dir}/log4j-1.2.16.jar" todir="${tmp.dir}/WEB-INF/lib"/>

           <!-- Using this file we are going to satisfy the log4j dependency without directly placing the log4j.jar inside "WEB-INF/lib"-->
           <copy file="${src.dir}/jboss-deployment-structure.xml" todir="${tmp.dir}/META-INF"/> 

           <jar jarfile="${tmp.dir}/${war.name}" basedir="${tmp.dir}" compress="true"/> 


           <copy file="${tmp.dir}/${war.name}" tofile="${output.dir}/${war.name}"/>
           <delete includeEmptyDirs="true">
              <fileset dir="${tmp.dir}"/>
           </delete>
        </target>
 
        <target name="deploy" depends="build">
            <echo message="*******************  Deploying the WAR file ${war.name} *********************" />
            <echo message="********** ${output.dir}/${war.name} to ${jboss.home}/standalone/deployments **********" />
            <copy todir="${jboss.home}/standalone/deployments/">
                <fileset dir="${output.dir}/">
                  <include name="${war.name}"/>
                </fileset>
            </copy>
            <echo message="*******************  Deployed Successfully   *********************" />
        </target>
</project>

NOTE: The only change in the above file you need to do is to change the “jboss.home” directory path in the second line of the above script to point to your own JBoss AS7 directory.

Step-9). Now before running your ANT script to build and deploy the above webapplication you should have the ANT as well as JAVA set in the $PATH variable of the Shell / command prompt as following:

For Unix Based OS:
export PATH=/home/userone/jdk1.6.0_21/bin:/home/userone/org.apache.ant_1.6.5/bin:$PATH

For Windows Based OS:
set PATH=C:/jdk1.6.0_21/bin;C:/org.apache.ant_1.6.5/bin;%PATH%

Step-10). Now once the PATH is set In the command/Shell prompt you can move inside the directory “/home/userone/jboss-as-7.1.0.Final/standalone/TESTING/ApplicationLevelLog4jDemo” and then run the ant to build & deploy the webapplication. by running the command “ant deploy”

[userone@localhost ApplicationLevelLog4jDemo]$ ant
Buildfile: build.xml

init:
   [delete] Deleting directory /home/userone/ApplicationLevelLog4jDemo/build
    [mkdir] Created dir: /home/userone/ApplicationLevelLog4jDemo/build
    [mkdir] Created dir: /home/userone/ApplicationLevelLog4jDemo/tmp
    [mkdir] Created dir: /home/userone/ApplicationLevelLog4jDemo/tmp/WEB-INF/lib
    [mkdir] Created dir: /home/userone/ApplicationLevelLog4jDemo/tmp/WEB-INF/classes
    [mkdir] Created dir: /home/userone/ApplicationLevelLog4jDemo/tmp/WEB-INF/META-INF
    [mkdir] Created dir: /home/userone/ApplicationLevelLog4jDemo/tmp/META-INF

build:
    [javac] Compiling 1 source file to /home/userone/ApplicationLevelLog4jDemo/tmp/WEB-INF/classes
     [copy] Copying 1 file to /home/userone/ApplicationLevelLog4jDemo/tmp/WEB-INF/classes
     [copy] Copying 1 file to /home/userone/ApplicationLevelLog4jDemo/tmp
     [copy] Copying 1 file to /home/userone/ApplicationLevelLog4jDemo/tmp/WEB-INF/classes
     [copy] Copying 1 file to /home/userone/ApplicationLevelLog4jDemo/tmp/WEB-INF/lib
     [copy] Copying 1 file to /home/userone/ApplicationLevelLog4jDemo/tmp/META-INF
      [jar] Building jar: /home/userone/ApplicationLevelLog4jDemo/tmp/Log4jDemo.war
     [copy] Copying 1 file to /home/userone/ApplicationLevelLog4jDemo/build

deploy:
     [echo] *******************  Deploying the WAR file Log4jDemo.war *********************
     [echo] ********** build/Log4jDemo.war to /home/userone/jboss-as-7.1.0.Final//standalone/deployments **********
     [copy] Copying 1 file to /home/userone/jboss-as-7.1.0.Final/standalone/deployments
     [echo] *******************  Deployed Successfully   *********************

BUILD SUCCESSFUL
Total time: 2 seconds

Step-11). Now you will able to access your application. “http://localhost:8080/Log4jDemo/index.jsp” try to access the servlet and then check the “${jboss.server.log.dir}/MyAppLogsFile.log” file to see if the application level logging is happening properly.

.
.
Thanks
Middleware Magic Team


Running Drools 5.3.0 Final in JBoss AS7

Hi,

Drools is a business rule management system (BRMS) with a forward chaining inference based rules engine. Drools can be called as “Business Logic integration Platform (BLiP)” – the BRMs is dead 🙂 The future is for a unified and integrated solution for Rules, Processes and CEP – this is what users want and this is what we are aiming for.
The best thing here is that “JBoss AS7 executes Drools much faster compared to other So Called Application Servers present in the market, which is needed by an Enterprise”.

Drools 5.0 has splited up into 4 main sub projects, the documentation has already been split to reflect this:
.

Drools Guvnor (BRMS/BPMS)
Drools Expert (rule engine),
Drools Flow (process/workflow)
Drools Fusion (cep/temporal reasoning)

Drools 5.4.0.Beta2 is the current release. It’s new features are mentioned in the following link: http://docs.jboss.org/drools/release/5.4.0.Beta2/droolsjbpm-introduction-docs/html/index.html

In this example we will mainly focus on following points

Point-1). In this example we will see how we can use a Drools 5.3.0.Final inside JBoss AS7 Application Server. This version of Drools can be downloaded from the following link : http://www.jboss.org/drools/downloads

Point-2). How to create a Drools module inside the JBoss AS7 so that the Jars which are provided by the Drools 5.3 will be available for the applications deployed on JBoss AS7.

Point-3). How to use simple Drools rule file and How to create the Drools Engine to execute those rules.

So here we will begin with the steps which can be used to run a drools based application inside JBoss AS7.
The Source code of this Demo is present in the following link:
https://github.com/jaysensharma/MiddlewareMagicDemos

JBoss AS7 Side Drools Module Configurations

Step-1). Here we are using JBoss AS7.1.0 CR1b which can be downloaded from the following link: http://www.jboss.org/jbossas/downloads. We are using “jboss-as-7.1.0.CR1b” in this demo.

Step-2). Download the Drools 5.3.0.Final from the following link “http://www.jboss.org/drools/downloads

Step-3). Extract the downloaded Drools “drools-distribution-5.3.0.Final.zip” (74.6 MB)

Step-4) Create a directory with name “drools/main” inside the JBoss AS7 modules directory “/home/userone/jboss-as-7.1.0.CR1b/modules”

Step-5) Copy and paste all the binaries (JAR) files from “drools-distribution-5.3.0.Final/binaries” and then paste them inside the “/home/userone/jboss-as-7.1.0.CR1b/modules/drools/main”

Step-6) Create a file “module.xml” inside “/home/userone/jboss-as-7.1.0.CR1b/modules/drools/main” as following:

<?xml version="1.0" encoding="UTF-8"?>
<module xmlns="urn:jboss:module:1.1" name="drools">
  <resources>
    <resource-root path="antlr-2.7.7.jar"/>
    <resource-root path="antlr-3.3.jar"/>
    <resource-root path="antlr-runtime-3.3.jar"/>
    <resource-root path="bcmail-jdk14-138.jar"/>
    <resource-root path="bcprov-jdk14-138.jar"/>
    <resource-root path="commons-collections-3.1.jar"/>
    <resource-root path="dom4j-1.6.1.jar"/>
    <resource-root path="drools-clips-5.3.0.Final.jar"/>
    <resource-root path="drools-compiler-5.3.0.Final.jar"/>
    <resource-root path="drools-core-5.3.0.Final.jar"/>
    <resource-root path="drools-decisiontables-5.3.0.Final.jar"/>
    <resource-root path="droolsjbpm-introduction-docs-5.3.0.Final.jdocbook"/>
    <resource-root path="drools-jsr94-5.3.0.Final.jar"/>
    <resource-root path="drools-persistence-jpa-5.3.0.Final.jar"/>
    <resource-root path="drools-templates-5.3.0.Final.jar"/>
    <resource-root path="drools-verifier-5.3.0.Final.jar"/>
    <resource-root path="ecj-3.5.1.jar"/>
    <resource-root path="ejb3-persistence-1.0.2.GA.jar"/>
    <resource-root path="google-collections-1.0.jar"/>
    <resource-root path="hibernate-annotations-3.4.0.GA.jar"/>
    <resource-root path="hibernate-commons-annotations-3.1.0.GA.jar"/>
    <resource-root path="hibernate-core-3.3.2.GA.jar"/>
    <resource-root path="hibernate-entitymanager-3.4.0.GA.jar"/>
    <resource-root path="itext-2.1.2.jar"/>
    <resource-root path="javassist-3.12.0.GA.jar"/>
    <resource-root path="jsr94-1.1.jar"/>
    <resource-root path="jta-1.1.jar"/>
    <resource-root path="jxl-2.6.10.jar"/>
    <resource-root path="knowledge-api-5.3.0.Final.jar"/>
    <resource-root path="log4j-1.2.14.jar"/>
    <resource-root path="mvel2-2.1.0.drools4.jar"/>
    <resource-root path="persistence-api-1.0.jar"/>
    <resource-root path="slf4j-api-1.6.0.jar"/>
    <resource-root path="stringtemplate-3.2.1.jar"/>
    <resource-root path="xml-apis-1.3.04.jar"/>
    <resource-root path="xmlpull-1.1.3.1.jar"/>
    <resource-root path="xpp3_min-1.1.4c.jar"/>
    <resource-root path="xstream-1.4.1.jar"/>
  </resources>
</module>

Step-7) Now Start your JBoss Profile as following from inside the directory “/home/userone/jboss-as-7.1.0.CR1b/bin”:
./standalone.sh -c standalone-full.xml

NOTE: If you don’t want to follow all the above 7 Steps to create a JBoss Module , then as an alternative you will need to place all the above JARs inside your Application’s “WEB-INF/lib” directory.

Developing Drools Based Application

Step-8). Create a directory somewhere in your file system as “/home/userone/DroolsTest” then create another directory “src” inside the “/home/userone/DroolsTest”.

Step-9). Create a directory with name “drools_lib” inside “/home/userone/DroolsTest” Just to place all the Jars of drools here. Copy and paste all the Jars from “drools-distribution-5.3.0.Final/binaries” to “home/userone/DroolsTest/drools_lib”. This step is just required to set the classpath in our ANT.

Step-10). Write a simple program “Message.java” as following inside the directory “/home/userone/DroolsTest/src”:

package test;
public class Message
  {
    public static final int HELLO   = 0;
    public static final int GOODBYE = 1;

    private String          message;
    private int             status; 

    public void setMessage(String message)
     {
         this.message=message;
         System.out.println("[Message] 'setMessage' method called with message : "+message);
     }
    public void setStatus(int status)
     {
         this.status=status;
         System.out.println("[Message] 'setStatus' method called with status : "+status);
     }
    public int getStatus()
     {
         System.out.println("[Message] 'getStatus' method called retuning status : "+status);
         return status;
     }
    public String getMessage()
     {
         System.out.println("[Message] 'getMessage' method called retuning message : "+message);
         return message;
     }
  }

Step-11). Write a simple Drools rule file “testRule.drl” as following inside the directory “/home/userone/DroolsTest/src”:

package rules
import test.Message;

rule "Hello World"
    when
        m : Message( status == Message.HELLO, myMessage : message )
    then
        System.out.println( myMessage );
        //m.setMessage( "Goodbye cruel world" );
        //m.setStatus( Message.GOODBYE );
        //update( m );
end


rule "GoodBye"
    when
        Message( status == Message.GOODBYE, myMessage : message )
    then
        System.out.println( myMessage );
end

Step-12). Write the Rule Engine program “MyRuleEngine.java” as following inside the directory “/home/userone/DroolsTest/src”

package engine;
import test.Message;

import java.io.IOException;
import org.drools.KnowledgeBase;
import org.drools.builder.KnowledgeBuilder;
import org.drools.KnowledgeBaseFactory;
import org.drools.builder.KnowledgeBuilderFactory;
import org.drools.builder.ResourceType;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatefulKnowledgeSession;

public class MyRuleEngine
  {
    /**
     * Creates a Drools KnowledgeBase and adds the given rules file into it
     */
    private static KnowledgeBase createKnowledgeBase( final String rulesFile ) {
        KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
        kbuilder.add( ResourceFactory.newClassPathResource( rulesFile ), ResourceType.DRL );
        KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
        kbase.addKnowledgePackages( kbuilder.getKnowledgePackages() );
        return kbase;
    }

    /**
     * Creates a Drools Stateful Knowledge Session
     */
    private static StatefulKnowledgeSession createKnowledgeSession( final KnowledgeBase kbase ) {
        final StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession();
        return ksession;
    }
    
     public static void executeRuleEngile(String rulesFile,String userInput) throws Exception
       {
          KnowledgeBase kbase = createKnowledgeBase(rulesFile);
          StatefulKnowledgeSession ksession = createKnowledgeSession(kbase);

          Message message = new Message();
          message.setMessage(userInput);
          message.setStatus(Message.HELLO);
          ksession.insert(message);

          ksession.fireAllRules();
          ksession.dispose();
       }  
  }

Step-13). Write a simple Servlet3.0 to invoke the rule engine “DroolsInvokerServlet.java” as following inside the directory “/home/userone/DroolsTest/src”:

package servlets;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.WebServlet;
 
@WebServlet(value="/DroolsInvokerServlet")
public class DroolsInvokerServlet extends HttpServlet
  {
     public void service(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException
       {
            PrintWriter out=res.getWriter();
            System.out.println("[DroolsInvokerServlet] Inside service() of DroolsInvokerServlet.");
            try
             {
               String ruleFile = "testRule.drl";
               System.out.println("[DroolsInvokerServlet] ruleFile = "+ruleFile);
               engine.MyRuleEngine.executeRuleEngile(ruleFile,"Hello World");
               out.println("Check JBoss Console for the Output of Drools Execution.");
             }
            catch(Exception e)
             {
                 System.out.println("[DroolsInvokerServlet] throws Exception: "+e);
                 e.printStackTrace();
             }
            System.out.println("Exiting service() of DroolsInvokerServlet.");
       }
  }

Step-14). Now we will just write a simple “index.jsp” file to invoke the above Servlet as following inside the directory “/home/userone/DroolsTest/src”:

<html>
  <head>
      <title>Drools Demo App</title>
  </head>
  <body>
      <center><h2>
         <a href="DroolsInvokerServlet">Click Here to hit the DroolsInvokerServlet</a>
      </h2></center>
  </body>
</html>

Step-15). Now we will write simple ANT build script “build.xml” which will build / deploy our Drools based application as following inside the directory “/home/userone/DroolsTest”:

<project name="RuleEngine_DroolsProject" default="deploy">
<property name="current.dir" value="." />
<property name="jboss.home" value="/home/userone/jboss-as-7.1.0.CR1b" />
<property name="drools.jar.dir" value="${current.dir}/drools_lib" />
<property name="jboss.module.dir" value="${jboss.home}/modules" />

<property name="basedir" value="." />
<property name="tmp.dir" value="tmp" />
<property name="output.dir" value="build" />
<property name="src.dir" value="src" />
<property name="war.name" value="DroolsHelloWorldDemo.war" />
 
        <path id="jboss.classpath">
           <fileset dir="${jboss.module.dir}">
              <include name="**/*.jar"/>
           </fileset>
           <fileset dir="${drools.jar.dir}">
              <include name="**/*.jar"/>
           </fileset>
        </path>
 
        <target name="init">
           <delete dir="${output.dir}" />
           <mkdir dir="${output.dir}" />
           <delete dir="${tmp.dir}" />
           <mkdir dir="${tmp.dir}" />
        </target>
 
        <target name="build" depends="init">
           <mkdir dir="${tmp.dir}/WEB-INF/lib"/>
           <mkdir dir="${tmp.dir}/WEB-INF/classes"/>
           <mkdir dir="${tmp.dir}/META-INF"/>

           <copy file="${src.dir}/index.jsp" tofile="${tmp.dir}/index.jsp"/>
           <copy file="${src.dir}/testRule.drl" todir="${tmp.dir}/WEB-INF/classes"/>
           <javac srcdir="${src.dir}" destdir="${tmp.dir}/WEB-INF/classes"  includes="*.java" classpathref="jboss.classpath"/>


           <!-- NOTE: we are creating a JAR which contains the  "testRule.drl" and the "engine.MyRuleEngine" class -->
           <jar jarfile="${tmp.dir}/WEB-INF/lib/MyDroolsApp.jar" basedir="${tmp.dir}/WEB-INF/classes" compress="true" />

           <copy todir="${tmp.dir}/WEB-INF">
                <fileset dir="${src.dir}">
                  <include name="*.java"/>
                </fileset>
           </copy>
           <delete dir="${tmp.dir}/WEB-INF/classes" />


           <!-- MOST IMPORTANT PART== Copy all the drools related Jars inside "WEB-INF/lib" If You don't want to create a JBoss Module 
           <copy todir="${tmp.dir}/WEB-INF/lib">
                <fileset dir="${drools.jar.dir}/">
                  <include name="*.jar"/>
                </fileset>
           </copy>
           -->

           <jar jarfile="${tmp.dir}/${war.name}" basedir="${tmp.dir}"  compress="true" >
              <manifest>
                 <!-- Make Sure that the [Dependencies: drools] is added in the ${war.name}/META-INF/MANIFEST.MF file -->
                 <attribute name="Dependencies" value="drools"/>
              </manifest>
           </jar>
           
           <copy file="${tmp.dir}/${war.name}" tofile="${output.dir}/${war.name}"/>
           <delete includeEmptyDirs="true">
              <fileset dir="${tmp.dir}"/>
           </delete>
        </target>
 
        <target name="deploy" depends="build">
            <echo message="*******************  Deploying the WAR file ${war.name} *********************" />
            <echo message="********** ${output.dir}/${war.name} to ${jboss.home}/standalone/deployments **********" />
            <copy todir="${jboss.home}/standalone/deployments/">
                <fileset dir="${output.dir}/">
                  <include name="${war.name}"/>
                </fileset>
            </copy>
            <echo message="*******************  Deployed Successfully   *********************" />
        </target>
</project>

NOTE: The only change in the above file you need to do is to change the “jboss.home” directory path in the second line of the above script to point to your own JBoss AS7 directory.

Step-16). Now before running your ANT script to build and deploy the above webapplication you should have the ANT as well as JAVA set in the $PATH variable of the Shell / command prompt as following:

For Unix Based OS:
export PATH=/home/userone/jdk1.6.0_21/bin:/home/userone/org.apache.ant_1.6.5/bin:$PATH

For Windows Based OS:
set PATH=C:/jdk1.6.0_21/bin;C:/org.apache.ant_1.6.5/bin;%PATH%

Step-17). Now once the PATH is set In the command/Shell prompt you can move inside the directory “/home/userone/DroolsTest” and then run the ant to build and deploy the Drools based application on your JBoss Standalone full profile, by running the command “ant deploy”

[userone@localhost DroolsTest]$ ant deploy
Buildfile: build.xml

init:
   [delete] Deleting directory /home/userone/DroolsTest/build
    [mkdir] Created dir: /home/userone/DroolsTest/build
   [delete] Deleting directory /home/userone/DroolsTest/tmp
    [mkdir] Created dir: /home/userone/DroolsTest/tmp

build:
    [mkdir] Created dir: /home/userone/DroolsTest/tmp/WEB-INF/lib
    [mkdir] Created dir: /home/userone/DroolsTest/tmp/WEB-INF/classes
    [mkdir] Created dir: /home/userone/DroolsTest/tmp/META-INF
     [copy] Copying 1 file to /home/userone/DroolsTest/tmp
     [copy] Copying 1 file to /home/userone/DroolsTest/tmp/WEB-INF/classes
    [javac] Compiling 3 source files to /home/userone/DroolsTest/tmp/WEB-INF/classes
      [jar] Building jar: /home/userone/DroolsTest/tmp/WEB-INF/lib/MyDroolsApp.jar
     [copy] Copying 3 files to /home/userone/DroolsTest/tmp/WEB-INF
   [delete] Deleting directory /home/userone/DroolsTest/tmp/WEB-INF/classes
      [jar] Building jar: /home/userone/DroolsTest/tmp/DroolsHelloWorldDemo.war
     [copy] Copying 1 file to /home/userone/DroolsTest/build

deploy:
     [echo] *******************  Deploying the WAR file DroolsHelloWorldDemo.war *********************
     [echo] ********** build/DroolsHelloWorldDemo.war to /home/userone/jboss-as-7.1.0.CR1b/standalone/deployments **********
     [copy] Copying 1 file to /home/userone/jboss-as-7.1.0.CR1b/standalone/deployments
     [echo] *******************  Deployed Successfully   *********************

BUILD SUCCESSFUL
Total time: 2 seconds

As soon as the WebService will be deployed on the JBoss AS7 you will see the following kind of output on your JBoss Console (STDOUT):


00:44:44,849 INFO  [org.jboss.as.server.deployment] (MSC service thread 1-3) Stopped deployment DroolsHelloWorldDemo.war in 84ms
00:44:44,850 INFO  [org.jboss.as.server.deployment] (MSC service thread 1-3) Starting deployment of "DroolsHelloWorldDemo.war"
00:44:44,913 INFO  [org.jboss.web] (MSC service thread 1-4) registering web context: /DroolsHelloWorldDemo
00:44:44,926 INFO  [org.jboss.as.server] (DeploymentScanner-threads - 2) JBAS018565: Replaced deployment "DroolsHelloWorldDemo.war" with deployment "DroolsHelloWorldDemo.war"

Step-18). Now we will try to access the Drools based application from the following URL:
http://localhost:8080/DroolsHelloWorldDemo/DroolsInvokerServlet

As soon as you will hit the above URL in the browser you will see that the rule got executed and the following kind of output you will see in the JBoss AS7 Console.

00:44:49,298 INFO  [stdout] (http-localhost-127.0.0.1-8080-3) [DroolsInvokerServlet] Inside service() of DroolsInvokerServlet.
00:44:49,298 INFO  [stdout] (http-localhost-127.0.0.1-8080-3) [DroolsInvokerServlet] ruleFile = testRule.drl
00:44:49,335 INFO  [stdout] (http-localhost-127.0.0.1-8080-3) [Message] 'setMessage' method called with message : Hello World
00:44:49,335 INFO  [stdout] (http-localhost-127.0.0.1-8080-3) [Message] 'setStatus' method called with status : 0
00:44:49,336 INFO  [stdout] (http-localhost-127.0.0.1-8080-3) [Message] 'getStatus' method called retuning status : 0
00:44:49,336 INFO  [stdout] (http-localhost-127.0.0.1-8080-3) [Message] 'getStatus' method called retuning status : 0
00:44:49,337 INFO  [stdout] (http-localhost-127.0.0.1-8080-3) [Message] 'getMessage' method called retuning message : Hello World
00:44:49,338 INFO  [stdout] (http-localhost-127.0.0.1-8080-3) Hello World
00:44:49,338 INFO  [stdout] (http-localhost-127.0.0.1-8080-3) Exiting service() of DroolsInvokerServlet.

Some Issues you may face

POINTER-A You may see a NullPointerException while loading the “testRule.drl” file inside your RuleEngine class. So to avoid that issue you should always place the Rule Engine class “engine.MyRuleEngine” and “testRule.drl” inside the same JAR file.

POINTER-B while using jboss module dependencies, If you see any ClassNotFoundException while invoking the Rules, which means the Drools classes are not loaded by JBoss or those jars are not available for your Application. So to avoid this issue better make sure that your WAR file has the right dependencies defined inside the “${WAR.FILE}/META-INF/MANIFEST.MF” as following:

Dependencies: drools

Where “drools” is the name of the module which we created in First 7 Steps of this article.

.
.
Thanks 🙂
Middleware Magic Team


Simplified FileUpload using Servlet3.0 in JBoss AS7

Hi,

Uploading files through web applications is one of the most important job of most of the applications. Earlier to servlet3.0 specification we used to do it manually, But now from Servlet 3.0 specification a very useful feature of file upload is associated. Servlet3.0 specification introduced annotation @javax.servlet.annotation.MultipartConfig and the API javax.servlet.http.Part to simplify the file upload.

Here “javax.servlet.http.Part” represents a part or form item that was received within a multipart/form-data POST request. And the @MultipartConfig indicating that instances of the Servlet expect requests that conform to the multipart/form-data MIME type. Servlets annotated with MultipartConfig may retrieve the Part components of a given multipart/form-data request by calling getPart or getParts.

In this example we will see how to uload files using the @MultipartConfig annotation and how to use the javax.servlet.http.Part API.

Step1). Our application is going to upload the files inside the server location “${jboss.server.base.dir}/upload” directory so make sure that we create a directory with name “upload” inside “${jboss.server.base.dir}”, Which means the following path should exist: “/home/userone/jboss-as-7.1.0.CR1b/standalone/upload”

Step2). Create a Directory somewhere inside your file system where we can create our web application. Suppose i am creating a directory as “/home/userone/EE6_FileUpload_Servlet” and the create a subdirectory with name “src” inside “/home/userone/EE6_FileUpload_Servlet”

Step3). We will place a simple “index.jsp” file inside “/home/userone/EE6_FileUpload_Servlet/src” directory which will present a html form to the user so that user can browse & upload the desired file.

<html>
    <head>
        <title>FileUpload Demo</title>
    </head>
    <body bgcolor="maroon" text="white">
      <center>
        <h1>FileUpload Demo Using Servlet3.0 in JBoss AS7</h1>
        <form id="formId" action="FileUploadServlet" enctype="multipart/form-data" method="post">
          <input type="file" id="FileUploadId" name="***Upload***"  /> 
          <input type="submit" id="uploadButtonId" value="Upload Now" />
        </form>   
      </center>
    </body>
</html>

Step4). Now we will write the “FileUploadServlet.java” program inside the “/home/userone/EE6_FileUpload_Servlet/src” directory which will be responsible for uploading the file provided by end user on the JBoss Server box.

package servlets;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletException;

//IOStream
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;

//Servlet3.0 specific annotations 
import javax.servlet.annotation.WebServlet;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.http.Part;

@WebServlet(description = "FileUploadServlet Description", urlPatterns = { "/FileUploadServlet" })
@MultipartConfig(location="/home/userone/EE6_FileUpload_Servlet")

public class FileUploadServlet extends HttpServlet {
 
    private static final long serialVersionUID = 1L;
    public FileUploadServlet()
        {
          super();
          System.out.println("FileUploadServlet Initialized & Instantiated.");
        }
 
    public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
        {
          PrintWriter out=response.getWriter();
          out.println("<html><head><body>");
          for (Part part : request.getParts()) 
              {
                  String fileName = "";
                  String partHeader = part.getHeader("content-disposition");
                  long partSize = part.getSize();
                  out.println("<BR>Part Name = "+part.getName());
                  out.println("<BR>Part Header = " + partHeader);
                  out.println("<BR>Part Size = " + partSize);
                  System.out.println("part.getHeader("content-disposition") = " + part.getHeader("content-disposition"));
               }
           out.println("<center><h1>File Upload Completed Successfully</h1></center></body></html>");


           //**** Custom Option ****//
           System.out.println("Custom Way To Upload File with Actual FileName.");
           fileUploadWithDesiredFilePathAndName(request);
           System.out.println("File Uploaded using custom Way.");
        }

    

     /* Following method allows us to place the uploaded file in a desired Location on the server along with the desired fileName */
     public void fileUploadWithDesiredFilePathAndName(HttpServletRequest request) throws IOException,ServletException
        {
          /******** Following part of code is not needed ********/
          InputStream inputStream = null;
          FileOutputStream outputStream =null;
          try
           {
             for (Part part : request.getParts()) 
               {
                  System.out.println(part.getName());
                  inputStream = request.getPart(part.getName()).getInputStream();
                  int i = inputStream.available();
                  byte[] b  = new byte[i];
                  inputStream.read(b);
                  System.out.println("Length : " + b.length);

                // Finding the fileName //
                  String fileName = "";
                  String partHeader = part.getHeader("content-disposition");
                  System.out.println("Part Header = " + partHeader);
                  System.out.println("part.getHeader("content-disposition") = " + part.getHeader("content-disposition"));

                  for (String temp : part.getHeader("content-disposition").split(";")) 
                     {
                       if (temp.trim().startsWith("filename")) 
                        {
                           fileName=temp.substring(temp.indexOf('=') + 1).trim().replace(""", "");
                        }
                     }

                  // Writing contents to desired FilePath & FileName //
                  String uploadDir=System.getProperty("jboss.server.base.dir")+"/upload";
                  System.out.println("File will be Uploaded at: " +uploadDir+"/"+fileName);                  
                  outputStream = new FileOutputStream(uploadDir +"/"+fileName);
                  outputStream.write(b);
                  inputStream.close();
               }
            }
          catch(Exception e)
            {
               System.out.println("Unable to Upload File: "+e);
               e.printStackTrace();
            }
          finally
            {
                if(inputStream!=null)
                   {   
                      try{ inputStream.close(); } catch(Exception e){ e.printStackTrace(); } 
                   }
                if(outputStream!=null)
                   {   
                      try{ outputStream.close(); } catch(Exception e){ e.printStackTrace(); } 
                   }
            }
        }
   }

NOTE:
The above servlet represents two ways to upload the file. One is purely using @MultipartConfig(location=”/home/userone/EE6_FileUpload_Servlet”) in this case the upload file location is specified but the uploaded file will have some random name, which is quite confusing some time.

So the above Servlet also has a separate method “fileUploadWithDesiredFilePathAndName(HttpServletRequest)” which extract the actual file name and places it in a desired location on the server box.

Step5). Now we will write a simple ant “build.xml” file in order to build and deploy our web application on JBoss AS7. So write the following “build.xml” file inside “/home/userone/EE6_FileUpload_Servlet” as following:

<project name="Servlet3FileUploadProject" default="deploy">
<property name="jboss.home" value="/home/userone/jboss-as-7.1.0.CR1b" />
<property name="jboss.module.dir" value="${jboss.home}/modules" />
<property name="basedir" value="." />
<property name="tmp.dir" value="tmp" />
<property name="output.dir" value="build" />
<property name="src.dir" value="src" />
<property name="war.name" value="Servlet3FileUploadDemo.war" />

        <path id="jboss.classpath">
           <fileset dir="${jboss.module.dir}">
              <include name="**/*.jar"/>
           </fileset>  
        </path>

        <target name="init">
           <delete dir="${output.dir}" />
           <mkdir dir="${output.dir}" />
           <delete dir="${tmp.dir}" />
           <mkdir dir="${tmp.dir}" />
        </target>
	 
        <target name="build" depends="init">
           <mkdir dir="${tmp.dir}/WEB-INF/classes"/>
           <copy file="${src.dir}/index.jsp" todir="${tmp.dir}"/>
           <javac srcdir="${src.dir}" destdir="${tmp.dir}/WEB-INF/classes"  includes="*.java" classpathref="jboss.classpath"/> 

           <copy todir="${tmp.dir}/WEB-INF">
                <fileset dir="${src.dir}/">
                      <include name="web.xml"/> 
                </fileset>
           </copy>          
           <jar jarfile="${tmp.dir}/${war.name}" basedir="${tmp.dir}" compress="true" />
      
           <!-- Clean up -->
           <copy file="${tmp.dir}/${war.name}" tofile="${output.dir}/${war.name}"/>
           <delete includeEmptyDirs="true">
              <fileset dir="${tmp.dir}"/>
           </delete> 
        </target>

        <target name="deploy" depends="build">
            <echo message="*******************  Deploying the WAR file ${war.name} *********************" />  
            <echo message="********** ${output.dir}/${war.name} to ${jboss.home}/standalone/deployments **********" />  
            <copy todir="${jboss.home}/standalone/deployments/">
                <fileset dir="${output.dir}/">
                  <include name="${war.name}"/> 
                </fileset>
            </copy>
            <echo message="*******************  Deployed Successfully   *********************" />  
        </target>
</project>

NOTE: The only change in the above file you need to do is to change the “jboss.home” directory path in the second line of the above script is to point to your own JBoss AS7 directory home directory.

Step6). Now before running your ANT script to build and deploy the above webapplication you should have the ANT as well as JAVA set in the $PATH variable of the Shell / command prompt as following:

For Unix Based OS:
export PATH=/home/userone/jdk1.6.0_21/bin:/home/userone/apache-ant-1.8.2/bin:$PATH

For Windows Based OS:
set PATH=C:/jdk1.6.0_21/bin;C:/apache-ant-1.8.2/bin;%PATH%

Step7). Now run the ant file from the directory where you have placed the “build.xml” file as following:

[userone@localhost httpOnlyDemo]$ ant

Buildfile: build.xml

init:
   [delete] Deleting directory /home/userone/EE6_FileUpload_Servlet/build
    [mkdir] Created dir: /home/userone/EE6_FileUpload_Servlet/build
    [mkdir] Created dir: /home/userone/EE6_FileUpload_Servlet/tmp

build:
    [mkdir] Created dir: /home/userone/EE6_FileUpload_Servlet/tmp/WEB-INF/classes
     [copy] Copying 1 file to /home/userone/EE6_FileUpload_Servlet/tmp
    [javac] Compiling 1 source file to /home/userone/EE6_FileUpload_Servlet/tmp/WEB-INF/classes
      [jar] Building jar: /home/userone/EE6_FileUpload_Servlet/tmp/Servlet3FileUploadDemo.war
     [copy] Copying 1 file to /home/userone/EE6_FileUpload_Servlet/build

deploy:
     [echo] *******************  Deploying the WAR file Servlet3FileUploadDemo.war *********************
     [echo] ********** build/Servlet3FileUploadDemo.war to /home/userone/jboss-as-7.1.0.CR1b/standalone/deployments **********
     [copy] Copying 1 file to /home/userone/jboss-as-7.1.0.CR1b/standalone/deployments
     [echo] *******************  Deployed Successfully   *********************

BUILD SUCCESSFUL
Total time: 3 seconds

Step8). Now access the application like following: “http://localhost:8080/Servlet3FileUploadDemo/index.jsp

NOTE: We will need to make sure that whatever upload directory we have choosen for this demo, Must already exist.
.
.
Thanks
MiddlewareMagic Team


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