Step by Step Installation and Configuration of WebLogic Server 12C

Installation

• Download the latest version of file from here. Accept the user license and select generic installer for latest Oracle weblogic server.
• Extract the installation jar from downloaded zip.
• Open a command window with administrator privilege. Navigate to the folder where the Jar is located.
• Run the following command.

  java -jar .jar

• Follow the on-screen instructions to install the weblogic server.

Domain Creation

• Navigate to <WebLogic_installation_directory>\Middleware\Oracle_Home\oracle_common\common\bin
• Run ‘config.cmd’. It would execute a wizard for domain creation.
• Select ‘Create a new domain’ -> browse to the base folder where you want your domain to be created -> Next.
• Create domain using product template -> Basic Weblogic Server Domain -> Next.
• Create an administrator account for the domain -> Next.
• Select domain mode -> Select JDK -> Next.
• In advanced configuration, check the ‘Administration Server’ box. For clustering and load balancing, ‘Topology’ configuration is also needed. These can be set up later from admin console.
• Enter Server name, listen address and port for Admin Server. This server provide the console for managing the domain -> Next.
• Review the setup configuration -> Create.

Starting Admin Server

• Navigate to the folder where the domain has been installed in previous step.
• Run the file ‘startWebLogic.cmd’ from the folder.
• When started, cmd will display ‘<Server state changed to RUNNING.>’.
• Open browser and navigate to URL. http://<serverAddress>:<serverport>/console. With default setting, the URL should be http://localhost:7001/console.
• With default setting, the admin console will be deployed on first access. Wait for few seconds for deployment to finish.
• Login to the console with username and password created while domain creation.
• The console screen can be used for all server configuration.

Deploying Web Application

• In the web console, from the left hand sidebar, select deployments.
• Click on install. It will open up the explorer in the console itself. Navigate to the war file, select it and click next.
• Select ‘Install this deployment as an application’ as installation scope -> Next.
• Give a name for this deployment. Keep the other setting as it is -> Next.
• If you have multiple server or cluster, you will be taken to server selection screen for deployment.
• Select finish. The application can be deployed to the server. The web application can be accessed through url http://<serverAddress>:<serverPort>/<ApplicationContextRoot>

Changing the Context Root of Web Application

Create a file name ‘weblogic.xml’ in WEB-INF folder of the web application. Add following to change the context root.

	<?xml version="1.0" encoding="UTF-8"?>
	<weblogic-web-app xmlns="http://xmlns.oracle.com/weblogic/weblogic-web-app">
	<context-root>/</context-root>
	</weblogic-web-app>

view raw weblogic.xml hosted with ❤ by GitHub

Step By Step Guide For Creating Drools Rules in Kie Workbench And Integrating It In External Java Application

Kie Workbench Side

Creating an organization, repository and project

• Login to Kie workbench with an ‘admin’ account.
• Create a new organization:
  • Authoring -> Administration -> Organizational Units -> Manage organizational Units -> Add
  • Give a name and group id to the organization.
• Create a new repository in the organization.
  • Authoring -> Administration -> Repositories -> New Repositories.
  • Give a name and select the organization
• Create a new project.
  • Authoring -> Project Authoring -> New Item -> New Project
  • Add a Project name and description.
  • Add Group ID (default value is organization id), Artifact id (default value is project name) and initial version number.

Creating a Rule

• Select the Organization, Repository and Project in the Project explorer.
• New Item -> Guided Rule
• Enter a name for the rule and select the package.
• Create the rule.

Adding external POJO model to the rules

The POJO model class that is needed by the workbench project need to be exported as a maven jar and uploaded to the workbench.

Uploading the POJO model class jar

• Authoring -> Artifact Repository -> Upload -> Browse to the Jar and upload
• If Jar does not contain a pom.xml file, you will be asked to manually enter a group and artifact id.

Adding model to the Project

• Navigate to the project -> Open Project Editor
• In project editor, from the dropdown, select Dependencies.
• Add from repository -> Select the model class jar file.

Adding and using model class in Rules.

• Open guided rule editor -> Navigate to the ‘Data Object’ tab.
• New item -> Choose a type.
• The type can be then used in rule editor.

Java Side

Accessing Workbench rule from external Java Application

• Setup drool runtime. Add following dependencies to the application pom.xml

  	<dependency>
  	<groupId>org.drools</groupId>
  	<artifactId>drools-core</artifactId>
  	<version>6.4.0.Final</version>
  	</dependency>
  	<dependency>
  	<groupId>org.kie</groupId>
  	<artifactId>kie-ci</artifactId>
  	<version>6.4.0.Final</version>
  	</dependency>
  	<dependency>
  	<groupId>org.drools</groupId>
  	<artifactId>drools-compiler</artifactId>
  	<version>6.4.0.Final</version>
  	</dependency>
  	<dependency>
  	<groupId>org.kie</groupId>
  	<artifactId>kie-internal</artifactId>
  	<version>6.4.0.Final</version>
  	</dependency>
  	<dependency>
  	<groupId>org.kie</groupId>
  	<artifactId>kie-api</artifactId>
  	<version>6.4.0.Final</version>
  	</dependency>
  	<dependency>
  	<groupId>org.drools</groupId>
  	<artifactId>drools-templates</artifactId>
  	<version>6.4.0.Final</version>
  	</dependency>
  	<dependency>
  	<groupId>org.jbpm</groupId>
  	<artifactId>jbpm-bpmn2</artifactId>
  	<version>6.4.0.Final</version>
  	</dependency>
  	<dependency>
  	<groupId>org.drools</groupId>
  	<artifactId>drools-decisiontables</artifactId>
  	<version>6.4.0.Final</version>
  	</dependency>

  view raw pom.xml hosted with ❤ by GitHub
• Add a new Repository to your maven. This is done by adding following line to settings.xml file residing in MAVEN_HOME folder. If there is no xml file, create one. Url tag must contain the link to the maven repository of kie workbench. The id of the repository must be ‘guvnor-m2-repo’.

  	<profiles>
  	<profile>
  	<activation>
  	<activeByDefault>true</activeByDefault>
  	</activation>
  	<repositories>
  	<repository>
  	<id>guvnor-m2-repo</id>
  	<name>Drools Workbench Repository Group</name>
  	<url>http://xyz/kie-drools-wb/maven2/</url>
  	<layout>default</layout>
  	<releases>
  	<enabled>true</enabled>
  	<updatePolicy>always</updatePolicy>
  	</releases>
  	</repository>
  	</repositories>
  	</profile>
  	</profiles>

  view raw settings.xml hosted with ❤ by GitHub
• Add the authentication details for the above repository in settings.xml file.

  	<servers>
  	<server>
  	<id>guvnor-m2-repo</id>
  	<username>naved</username>
  	<password>naved</password>
  	</server>
  	</servers>

  view raw settings.xml hosted with ❤ by GitHub
• Java code to access the repositories and run the rules.

  	KieServices ks = KieServices.Factory.get();
  	KieContainer kieContainer = ks.newKieContainer(ks.newReleaseId("Testorganization", "ShoppingDiscount", "1.0.9-SNAPSHOT"));
  	KieSession kieSession = kieContainer.newKieSession();
  	kieSession.insert(item);
  	kieSession.fireAllRules();kieSession.fireAllRules();

  view raw Hello.java hosted with ❤ by GitHub
  In the release id, we need to pass the Group ID, Artifact ID and version number of the workbench project.

KieScanner and Repository Updation

KieServices tend to download the remote repository only once in a day and store it in local repository. We can however use the KieScanner and force the container to scan for any update in the remote repository. A scan will only update the local repository if we are using ‘LATEST’ as the version number and a new version of the repository is available in remote directory or the remote repository is in development stage (denoted by ‘-SNAPSHOT’ appended to the version number).

	KieScanner kieScanner = ks.newKieScanner(kieContainer);
	kieScanner.scanNow(); // kieScanner.start(pollingInterval);

view raw Hello.java hosted with ❤ by GitHub

Installing KIE workbench in Apache Tomcat 7 in Windows

KIE Drools Workbench

KIE workbench is the workflow engine where complex business process can be develop and executed. It also provide interface to create guided and DRL rules. The workbench can be linked through a Java application to use the created rule in our application.

Installing KIE workbench in Apache Tomcat 7 in Windows

• Download the Kie workbench from http://download.jboss.org/drools/release/6.4.0.Final/kie-drools-wb-distribution-wars-X.X.X.Final-tomcat7.war. The X.X.X is version of the workbench. It must correspond to the version of Drools engine used.
• The war file downloaded need to be deployed in the web-app folder of Apache tomcat.
• Download and copy following jar files into TOMCAT_HOME/lib
  • btm-2.1.4.jar
  • btm-tomcat55-lifecycle-2.1.4.jar
  • h2-1.3.161.jar
  • jta-1.1.jar
  • slf4j-api-1.7.2.jar
  • slf4j-jdk14-1.7.2.jar
  • kie-tomcat-integration
  • JACC (javax.security.jacc:artifactId=javax.security.jacc-api in JBoss Maven Repository)
• Create configuration files inside TOMCAT_HOME/conf
  • btm-config.properties

    	bitronix.tm.serverId=tomcat-btm-node0
    	bitronix.tm.journal.disk.logPart1Filename=${btm.root}/work/btm1.tlog
    	bitronix.tm.journal.disk.logPart2Filename=${btm.root}/work/btm2.tlog
    	bitronix.tm.resource.configuration=${btm.root}/conf/resources.properties

    view raw btm-config.properties hosted with ❤ by GitHub
  • resources.properties

    	resource.ds1.className=bitronix.tm.resource.jdbc.lrc.LrcXADataSource
    	resource.ds1.uniqueName=jdbc/jbpm
    	resource.ds1.minPoolSize=10
    	resource.ds1.maxPoolSize=20
    	resource.ds1.driverProperties.driverClassName=org.h2.Driver
    	resource.ds1.driverProperties.url=jdbc:h2:file:C:/apache-tomcat-7.0.53/temp2
    	resource.ds1.driverProperties.user=sa
    	resource.ds1.driverProperties.password=
    	resource.ds1.allowLocalTransactions=true

    view raw resources.properties hosted with ❤ by GitHub
    
    The Path in above file need to be change to the actual system path.

Create setenv.sh (or setenv.bat) file inside TOMCAT_HOME/bin and add following:

set CATALINA_OPTS=-Xmx512M -XX:MaxPermSize=512m -Dbtm.root=C:\apache-tomcat-7.0.53\ -Dbitronix.tm.configuration=C:\apache-tomcat-7.0.53\conf\btm-config.properties -Djbpm.tsr.jndi.lookup=java:comp/env/TransactionSynchronizationRegistry -Djava.security.auth.login.config=C:\apache-tomcat-7.0.53\webapps\kie-drools-wb\WEB-INF\classes\login.config -Dorg.jboss.logging.provider=jdk -Dorg.uberfire.nio.git.dir=C:/apache-tomcat-7.0.53/temp

view raw setenv.bat hosted with ❤ by GitHub

Add valve configuration into TOMCAT_HOME/conf/server.xml inside Host element as last valve definition:

<Valve className="org.kie.integration.tomcat.JACCValve" />

view raw server.xml hosted with ❤ by GitHub

Edit TOMCAT_HOME/conf/tomcat-users.xml to include roles and users, make sure there will be 'analyst' or 'admin' roles defined as it's required to be authorized to use kie-wb

	<user username="tomcat" password="tomcat" roles="manager-gui"/>
	<user username="naved" password="naved" roles="admin"/>

view raw tomcat-users.xml hosted with ❤ by GitHub

Start tomcat and open url http://127.0.0.1:8080/kie-drools-wb- distribution-wars-X.X.X.Final-tomcat7

Installing Drools in Eclipse and Creating Simple Hello World Application in Drools

Drools

• Drools is a Business rule management system
• It is used to separate the data from logic.
• It allow us to write logic (rules) in more layman readable form. This allow business people to create their own rules instead of depending on programmers and developers.

Rules

Rules are pieces of knowledge often expressed as, "When some conditions occur, then do some tasks."
The most important part of a Rule is it’s when part. If the when part is satisfied, the then part is triggered

	rule <rule_name>
	<attribute> <value>
	when
	<conditions>
	then
	<actions>
	end

view raw sample.drl hosted with ❤ by GitHub

Installing Drools in Eclipse

Drools comes with plugin for eclipse to create and manage the project from eclipse itself.

Prerequisites to install Drools Plugin:

• Java 1.5 (or higher)
• Eclipse 4.2

Installation Step

• Download the latest binaries from http://download.jboss.org/drools/release/
• Launch Eclipse -> help -> install new software -> Add.
  • Name – Drools
  • Location - http://download.jboss.org/drools/release/X.X.X.Final/org.drools.updatesite/
    where X.X.X is version of drool downloaded.
  • Click Ok
• Checkmark “Drools and jBPM”. Click next. Accept the terms and wait for installation to finish.

Drools Runtime

Drool runtime is needed to create and execute drool rules.

• Click on Windows -> Preference -> Drools -> Installed Drools Runtime -> Add -> Browse.
• Browse to the downloaded binaries folder and Add.

Example Project

1. File -> New -> Drool Project -> Create an empty project.
2. Enter project name -> finish.
3. The project follow maven folder structure. Two primary folder are
   1. src/main/java – Java code would go here.
   2. src/main/resources – Drool files would go here.
4. Create a new java class file in src/main/java. Say ‘Hello.java’ in package ‘com.example’.

   	package com.example;
   	import org.kie.api.KieServices;
   	import org.kie.api.runtime.KieContainer;
   	import org.kie.api.runtime.KieSession;
   	public class Hello {
   	private String hellostr = "Hello World";
   	public String getHellostr() {
   	return hellostr;
   	}
   	public void setHellostr(String hellostr) {
   	this.hellostr = hellostr;
   	}
   	public static void main(String[] args) {
   	Hello hello = new Hello();
   	System.out.println("String before firing rule: "+hello.getHellostr());
   	// Create knowledge base from default drool file.
   	// The default folder from where knowledge base will read
   	// drool file is defined /src/main/resources/META-INF/kmodule.xml
   	// The default value in this generated file is /src/main/resources/rules
   	KieServices ks = KieServices.Factory.get();
   	KieContainer kContainer = ks.getKieClasspathContainer();
   	KieSession kSession = kContainer.newKieSession("ksession-rules");
   	kSession.insert(hello);
   	kSession.fireAllRules();
   	System.out.println("String after firing rule: "+hello.getHellostr());
   	}
   	}

   view raw Hello.java hosted with ❤ by GitHub
5. Create a new drool file in src/main/resources/rules. Say ‘ReplaceHello.drl’.

   	import com.example.Hello;
   	rule "SayGoodBye"
   	when
   	h : Hello(hellostr.contains("Hello"))
   	then
   	h.setHellostr(h.getHellostr().replace("Hello","Goodbye"));
   	end

   view raw ReplaceHello.drl hosted with ❤ by GitHub
6. Result.

   	String before firing rule: Hello World
   	String after firing rule: Goodbye World

   view raw Result hosted with ❤ by GitHub

Apart from creating the rules file in resources folder, we can import the rules files from classpath as well as file system. Below example show an example of reading the rule file from classpath.

	KieServices ks = KieServices.Factory.get();
	KieFileSystem kieFileSystem = ks.newKieFileSystem();
	kieFileSystem.write(ResourceFactory.newClassPathResource("myrule/HelloRule.drl"));
	KieBuilder builder = ks.newKieBuilder(kieFileSystem).buildAll();
	KieContainer kContainer = ks.newKieContainer(ks.getRepository().getDefaultReleaseId());
	KieSession kSession = kContainer.newKieSession();
	if(builder.getResults().hasMessages(Level.ERROR)) {
	throw new RuntimeException(builder.getResults().toString());
	}

view raw Hello.java hosted with ❤ by GitHub

Block Swap Algorithm for Array Rotation

	#include <iostream>
	#include <cstdio>
	using namespace std;
	void swap(int nums[],int start,int end,int d)
	{
	for(int i=0;i<d;i++) {
	int t=nums[start+i];
	nums[start+i]=nums[end+i];
	nums[end+i]=t;
	}
	}
	void rotateLeft(int* nums, int numsSize, int k) {
	k = k%numsSize;
	if(k==0 || k==numsSize)
	return;
	if(numsSize-k==k)
	{
	swap(nums,0,k,k);
	return;
	}
	if(k<numsSize-k) {
	swap(nums,0,numsSize-k,k);
	rotateLeft(nums,numsSize-k,k);
	}
	else {
	swap(nums,0,k,numsSize-k);
	rotateLeft(nums+numsSize-k,k,2*k-numsSize);
	}
	}
	void rotateRight(int* nums, int numsSize, int k) {
	k = k%numsSize;
	if(k==0 || k==numsSize)
	return;
	if(numsSize-k==k)
	{
	swap(nums,0,k,k);
	return;
	}
	if(k<numsSize-k) {
	swap(nums,0,numsSize-k,k);
	rotateRight(nums+k,numsSize-k,k);
	}
	else {
	swap(nums,0,k,numsSize-k);
	rotateRight(nums,k,2*k-numsSize);
	}
	}
	int main() {
	int n,k;
	cin>>n>>k;
	int arr[n];
	for(int i=0;i<n;i++)
	cin>>arr[i];
	rotateLeft(arr,n,k);
	cout<<"After Left Rotation : ";
	for(int i=0;i<n;i++)
	cout<<arr[i]<<" ";
	cout<<endl;
	rotateRight(arr,n,k);
	cout<<"After Right Rotation : ";
	for(int i=0;i<n;i++)
	cout<<arr[i]<<" ";
	cout<<endl;
	}

view raw RotateArrayByBlockSwap hosted with ❤ by GitHub

Linux Memory Layout Test through C

If you have gone through any Operating System Course, you would have come across the Memory Layout Diagram of a Process in physical RAM. Below diagram show the layout of a process in the memory:

But, the question is how does these layout actually maps to a program that i have written?
Without an example with an actual running program, this concept seems vague and is pretty hard to visualize. I have written a C program to actually verify this layout in the memory. Here is the C code:

	#include<stdio.h>
	#include<stdlib.h>
	#pragma GCC optimize ("O0")
	// uninitialized variable
	int g1;
	int g2;
	//iniatialized variable
	int g3=5;
	int g4=7;
	// function to test stack
	void func2() {
	int var1;
	int var2;
	printf("On Stack through func2:\t\t %u %u\n",&var1,&var2);
	}
	void func() {
	int var1;
	int var2;
	printf("On Stack through func:\t\t %u %u\n",&var1,&var2);
	func2();
	}
	int main(int argc, char* argv[], char* evnp[]) {
	// Command line arguments
	printf("Cmd Line and Env Var:\t\t %u %u %u\n",&argc,argv,evnp);
	// Local variable will go to stack and stack should grow downward
	int var1;
	int var2;
	printf("On Stack through main:\t\t %u %u\n",&var1,&var2);
	func();
	// Dynamic Memory should go to heap and should be increasing
	void *arr1 = malloc(5);
	void *arr2 = malloc(5);
	printf("Heap Data:\t\t\t\t\t %u\n",arr2);
	printf("Heap Data:\t\t\t\t\t %u\n",arr1);
	free(arr1);
	free(arr2);
	// Uninitialized and iniatialized Global Variable
	printf("Global Uniniatialized:\t\t %u %u\n",&g1,&g2);
	printf("Global iniatialized:\t\t %u %u\n",&g3,&g4);
	//Static Code must go to Text section
	printf("Text Data:\t\t\t\t\t %u %u ",main,func);
	return 0;
	}

view raw gistfile1.c hosted with ❤ by GitHub

From this source code, let us try to predict where this variables would actually be getting stored in the memory.

We know that command line arguments and environment variable goes to the highest memory available to the process. Therefore, the address for this variables must be greater than any other variable or function address.

Next comes the stack. First function that is called in our program is main function itself which makes a call to func which in turn calls func2. Therefore, main should be at the bottom of the stack followed by func and func2 respectively. Mapping this stack into the memory, as stack grows from high memory to low memory, memory address of local variable of main should be greater than (but should be close to) local variable of func whereas func2's local variable should be having the lowest memory address among the three.

On the other hand, heap start from other side (lower address side) and grows toward stack. Therefore any memory allocated on heap should have address lower than any memory on stack. Our dynamic memory arr2 is allocated after arr1. Therefore, address of arr2 should be greater than arr1, as heap grow toward higher memory side.

Third section is data section which comprises of initialized and uninitialized data. Data section lies just below the heap. Hence, it address must be always less than any memory in heap or above heap. Also, uninitialized data is followed by initialized data. Therefore, address of any uninitialized data must be greater than that of initialized data. This behavior can be seen with the variable g1, g2, g3 and g4.

At last comes the text section which stores the read-only code. These falls at the bottom of the memory allocated to process and must be having address lower than any other section.

Here is the sample output of the program when run at ideone. Click on the link to see the run output at their site itself. I am pasting the same here:

	Cmd Line and Env Var: 3216684080 3216684228 3216684236
	On Stack through main: 3216684052 3216684048
	On Stack through func: 3216684012 3216684008
	On Stack through func2: 3216683964 3216683960
	Heap Data: 144969752
	Heap Data: 144969736
	Global Uniniatialized: 134519328 134519332
	Global iniatialized: 134519320 134519316
	Text Data: 134513984 134513936

view raw gistfile1.txt hosted with ❤ by GitHub

You can verify that this conforms to above discussion. Here is a above memory layout diagram modified for our program:

Setting and Getting Environment Variable in C

There are a number of way by which you can access environment variable in C. Most common of them is to declare as

main(int argc,char* argv[], char** envp)

view raw gistfile1.c hosted with ❤ by GitHub

envp contains all environment strings. Here is an example program:

	#include<stdio.h>
	int main(int argc, char* argv[], char* evnp[]) {
	int i;
	for(i=0; evnp[i]!=NULL; i++) {
	printf("%s\n",evnp[i]);
	}
	}

view raw gistfile1.txt hosted with ❤ by GitHub

We can also use external variable 'environ' to get all the environment variable.
Here is an example program:

	#include<stdio.h>
	extern char** environ;
	int main(int argc, char* argv[]) {
	int i;
	for(i=0; environ[i]!=NULL; i++) {
	printf("%s\n",environ[i]);
	}
	}

view raw gistfile1.txt hosted with ❤ by GitHub

Also,there are function available in stdlib through which we can access any particular environment variable as well as add and modify them. getenv is use to get value of an environment variable whereas setenv is use to add and replace them. setenv also takes an optional parameter which specify whether we want to overwrite any existing variable or not.

Here is a sample program:

	#include<stdio.h>
	#include<stdlib.h>
	void myGetenv (const char * name)
	{
	char * value = getenv (name);
	if (! value) {
	printf ("%s is not set.\n", name);
	}
	else {
	printf ("%s = %s\n", name, value);
	}
	}
	int main(int argc, char* argv[], char* evnp[]) {
	// Variable is not set.
	myGetenv ("myVar");
	setenv ("myVar", "TestVal", 0);
	myGetenv ("myVar");
	// This doesn't change the value because "overwrite" is 0.
	setenv ("myVar", "SecondValue", 0);
	myGetenv ("myVar");
	// This changes the value because "overwrite" is 1.
	setenv ("myVar", "SecondValue", 1);
	myGetenv ("myVar");
	}

view raw gistfile1.c hosted with ❤ by GitHub

The output of above code would be:

	myVar is not set.
	myVar = TestVal
	myVar = TestVal
	myVar = SecondValue

view raw gistfile1.txt hosted with ❤ by GitHub