How to Use a Rule Session in Java EE

Samples > Rule Execution Server Integration > How to Use a Rule Session in Java EE

How to Use a Rule Session in Java EE

The sample shows you how to execute a simple stateless rule session on a Java EE application server. You can execute the sample on the Web using Java Server Pages (JSP), or by using a Java client.

Key Features

Key features include:

Stateless EJB rule session and stateless simple rule session (POJO)
Rule Execution Server management model IlrJmxMutableModel
Rulesets archive (.jar files)
A Java XOM (Execution Object Model) for the shop model
Execution report
JSR 94: JavaTM Rule Engine API Specification 1.0 (http://jcp.org/en/jsr/detail?id=94)

Installing the Sample

Before installing the sample, you will need to start the Rule Execution Server Console using:

The Samples Console: When you open the Samples Console the JBoss Samples Server is automatically started and Rule Execution Server pre-deployed.
Other supported application servers: Install Rule Execution Server on your application server. See Installing JRules Modules.

Configuring the Samples Property File

If you are using an application server other than the JBoss Samples Server, configure the sample property files for your application server as follows:

WebLogic:

<InstallDir>/executionserver/samples/j2eerulesession/weblogic92|100/build.properties:

WL_HOME=${env.WL_HOME}. By default the variable is set to your WL_HOME environment variable.

<InstallDir>/executionserver/samples/j2eerulesession/weblogic92|100/jndi.properties:

java.naming.provider.url=<JNDIService>. This defines the URI of the machine running the JNDI service. For example: java.naming.provider.url=t3://localhost:7001/

WebSphere:

<InstallDir>/executionserver/samples/j2eerulesession/websphere6/build.properties:

WAS_HOME=${env.WAS_HOME}. By default the variable is set to your WAS_HOME environment variable.

<InstallDir>/executionserver/samples/j2eerulesession/websphere6/jndi.properties:

java.naming.provider.url=<JNDIService>. This defines the URI of the machine running the JNDI service.

JBoss:

<InstallDir>/executionserver/samples/j2eerulesession/jboss40/build.properties:

jboss.home=<JBoss_Installation_Directory> . By default the path is set to the Samples Server.

jboss.config=<JBoss_Configuration>. By default this property is set to the configuration file of the Samples Server.

<InstallDir>/executionserver/samples/j2eerulesession/jboss40/jndi.properties:

java.naming.provider.url=<JNDIService>. This defines the URI of the machine running the JNDI service. By default, this property is set to the Samples Server URI.

Sun AS 82:

<InstallDir>/executionserver/samples/j2eerulesession/sunas82/build.properties:

SUNAS82_HOME=${env.SUNAS_HOME}. By default the variable is set to your SUNAS_HOME environment variable.

Oracle10g:

<InstallDir>/executionserver/samples/j2eerulesession/oracle10g/build.properties:

ORACLE_HOME=${env.ORACLE_HOME}. By default the variable is set to your ORACLE_HOME environment variable.

<InstallDir>/executionserver/samples/j2eerulesession/oracle10g/jndi.properties:

java.naming.provider.url=<JNDIService>. This defines the URI of the machine running the JNDI service.

Building the Sample

You need to build the sample if you are using an application server other than the JBoss Samples Server.

To build the sample:

Go to the Samples Console and locate the sample executionserver > j2eerulesession > <APPLICATION_SERVER_NAME>

where <APPLICATION_SERVER_NAME> is one of the following:

- weblogic92 for WebLogic 9.2

- weblogic100 for WebLogic 10.0

- websphere6 for WebSphere 6.1

- jboss40 for JBoss 4.0

- oracle10g for Oracle10g AS

- sunas82 for Sun AS 82

Execute the ear command to build the XOM classes and package the following files:

- the Web Archive Resource (WAR) including the JSPs

- the rule session Java Archive Resources (JARs)

- the Enterprise Archive Resource (EAR)

The EAR file is generated in the directory <JRULES_HOME>/executionserver/samples/j2eerulesession/<APPLICATION_SERVER_NAME>/build.

Installing the Sample on JBoss

To install the sample on JBoss through the sample server:

Start the Samples Console and wait for it to complete (the Samples documentation will open).
In the Samples Explorer open:

executionserver/j2eerulesession/jboss40/J2eerulesession Sample: JBoss platform

Double-click ear.
When the build is successful, double-click deploy.

The EARs for the other application servers should be deployed through the respective application server console.

Running the Sample

The sample can only be run through the Samples Console.

To run the sample:

Open a web browser and type the appropriate URL for your application server:

JBoss Samples Server: http://localhost:8080/rulesession

WebLogic 9.2/10.0: http://localhost:7001/rulesession

WebSphere 6.1: http://localhost:9080/rulesession

JBoss 4.0: http://localhost:8080/rulesession

Oracle10g: http://localhost:8888/rulesession

SunAS 82: http://localhost:8080/rulesession

Username: bres

Password: bres

Click the RuleApp Management tab. The list of available rulesets are displayed.
Click the View to view BAL rules contained in the ruleset.
Click Deploy to deploy the ruleset (for example, balsample2).
Select the Execution tab.

The Java (POJO) rule session produces an execution report. In the section Rules execution each icon represents a different mode of launching a ruleset. For more information about these three modes, see Execution.

Click the icon under Java Rule Session.
Examine the rule execution results and the execution report:

Execution results:

- Messages: Displays any output parameters whose values are affected by the execution of the rules

- Normal Price: The normal price of the item.

- Discount: The discount calculated by the rules.

- Final Price: The cost of the item minus the calculated discount.

Execution report:

Using the IlrExecutionResult class, you have access to a lot of information about the execution, such as: working memory, execution times, number of rules fired, and so on. In the sample we have displayed the following information:

- The number of rules fired

- The rules fired

- Execution time

You can also execute the rules remotely using a Java client, as follows:

Go to the Samples Console and locate the sample: executionserver > j2eerulesession > <APPLICATION_SERVER_NAME>

where <APPLICATION_SERVER_NAME> is one of the following:

- weblogic92 for WebLogic 9.2

- weblogic100 for WebLogic 10.0

- websphere6 for WebSphere 6.1

- jboss40 for JBoss 4.0

- oracle10g for Oracle10g AS

- sunas82 for Sun AS 82

Ensure that you have deployed the ruleset, as described in Step 5.
Execute the run command.

The Java client connects to the Remote EJB Rulesession, executes the rules and displays the output.

Source Files

The sample is located in:

<InstallDir>/executionserver/samples/j2eerulesession

The XOM source files located are in:

<InstallDir>/executionserver/samples/j2eerulesession/src/shopmodel

Customer is the XOM class of a customer.
Item is the XOM class of an item.
ItemType is the XOM class of an item type.
ShoppingCart is the XOM class of a shopping cart.

The source files for the web tier control classes are located in:

<InstallDir>/executionserver/samples/j2eerulesession/src/controller

ComponentSessionListener
RuleAppController
RuleExecutionController: -- this class provides two generic methods to execute the sample ruleset, using the JSR-94 API and the JRules vendor API. It also provides methods that demonstrate how to use the same JRules vendor API-based source code to execute a ruleset using a Javabean, a local EJB, or a remote EJB-based rule session.
Webutil: Utility class used in the Web tier.
MySessionProvider

The source file for the Java remote client is located in:

<InstallDir>/executionserver/samples/j2eerulesession/src/client

RemoteJavaClient -- this is a Java SE program that remotely invokes the stateless rule session and re-uses the methods provided by the sample RuleExecutionController class.

The JSP source files are located in:

<InstallDir>/executionserver/samples/j2eerulesession/src/WebContent