Execution and management stacks

The execution, management, and monitoring stacks are similar for Java™ SE and Jakarta EE but the packaging and lookup mechanisms differ.

Rule Execution Server targets and provides services for the following environments:

Java SE and Jakarta EE runtime environments
Java SE and Jakarta EE management environments
Client development and deployment cycles

The following figure shows the execution stack and the management and monitoring stacks. They are similar for Java SE and Jakarta EE.

Diagram of the execution and the management/monitoring stacks

However, the Java SE and Jakarta EE stacks differ in the packaging and lookup mechanisms.

Because Rule Execution Server is supported in Java SE, developers can use rule sessions to execute ruleset archives outside an application server. Developers can also deploy RuleApps directly to the JDBC-compliant database or file system by running either a res-write Ant task or in the Rule Execution Server console. For details about the rule session API, see ilog.rules.res.session.

The certified web container to run the management stack in Java SE is Tomcat. Tomcat provides the minimum set of facilities to handle the stack: JMX, JNDI, and JDBC data source handling. You can also deploy the management stack on a Jakarta EE application server. With the management stack, users can both rely on the infrastructure for storing and deploying ruleset archives and execute rules in a pure Java SE environment.

Rule execution tests over the Rule Execution Server console run through the execution unit (XU) directly.

The following table shows the Java SE or Jakarta EE modes of the deployed stacks.

Table 1. Rule Execution Server stack configurations
Mode	Execution Stack	Management Stack
Java SE	Use classpath-executionserver.xml and classpath-engine.xml to set the JAR files for Java SE execution.	Non applicable
Java SE	Use the res-write Ant task to deploy rulesets. Use the res-write-xom Ant task to deploy Java XOM resources
Java SE with management support	Use classpath-executionserver.xml and classpath-engine.xml to set the JAR files for Java SE execution. Optional deployment of jrules-ssp-`<appserver>`.ear and jrules-res-htds`<platform>`.ear. For Tomcat:DecisionService.war	jrules-res-management`<platform>`.war. For Tomcat:res.war.
Java SE with management support	In this configuration, no execution statistics are available and, by default, no hot ruleset update. You can flush the connection pool by calling the IlrManagementSession#invalidate(ilog.rules.res.model.IlrPath) method on the ruleset. Restriction: Do not use the res-write Ant task because it might desynchronize the Rule Execution Server console from changes to the data source. If you activate the TCP/IP management mode of the Rule Execution Server console, you can monitor execution unit (XU) instances that are not running in the same Java virtual machine (JVM) as the console.
Java SE with management and monitoring support	Use classpath-executionserver.xml and classpath-engine.xml to set the JAR files for Java SE execution. Package the execution stack as a web application. Optional deployment of jrules-ssp-`<appserver>`.ear and jrules-res-htds`<platform>`.ear. For Tomcat:DecisionService.war	jrules-res-management`<platform>`.war (res.war for Tomcat) in the same JVM.
Java SE with management and monitoring support	Full management capabilities.
Jakarta EE application-scoped	jrules-res-xu-`<platform>`.rar packaged inside an EAR file. Optional deployment of jrules-ssp-`<appserver>`.ear and jrules-res-htds`<platform>`.ear (DecisionService.war for Tomcat).	One management EAR on a Jakarta EE application server.
Jakarta EE application-scoped	In this configuration, Rule Execution Server is limited to the application in which it is packaged. When you use such embedded deployment, bear in mind the following points: Use distinct JNDI names to avoid naming conflicts. Upgrade all your applications when you patch Decision Server. Make sure that you do not have a server-wide RAR deployment, then embed the RAR in an application on the same server.
Jakarta EE server-scoped	jrules-res-xu-`<platform>`.rar deployed on an application server. Optional deployment of jrules-ssp-`<appserver>`.ear and jrules-res-htds`<platform>`.ear. (DecisionService.war for Tomcat)	One management EAR on a Jakarta EE application server.
Jakarta EE server-scoped	Full management capabilities.