JRules engine mode

The JRules engine mode specifies the type of interface that the connector uses to locate the ruleset and configure the stage at design time and to establish the JRules session and invoke the ruleset at runtime.

Core engine
In this engine mode, the connector accesses the JRules engine directly through the engine JAR file. The connector points the JRules engine to the physical ruleset archive file that contains the definition of the ruleset to be executed.
To use this mode, you must export the ruleset as a ruleset archive. The ruleset is exported as a JAR file that must be copied on the machine on which IBM® InfoSphere® Information Server engine is running. The path of this JAR file must be specified in the Ruleset location stage property.
J2SE RES XU mode
In this engine mode, the JRules engine runs as a locally managed Rule Execution Server (RES) in the same Java™ process as the connector. To invoke the ruleset, the connector points the JRules engine to the ruleset definition in the ruleset repository.
The ruleset repository can either be a file-based repository or a database-based repository. If the repository is file-based, then it must be on the same machine on which IBM InfoSphere Information Server engine is running. The configuration on whether to use a file-based repository or a database-based repository is specified in the ra.xml JRules configuration file. For more information about the configuration file, see the JRules documentation. When using this engine mode the Ruleset location stage property specifies the path of the ruleset in the repository.
J2EE RES XU mode
In this engine mode, the JRules engine runs as a remotely managed RES on the Java 2 Platform, Enterprise Edition (Java EE) server. To invoke the ruleset, the connector points the JRules engine to the ruleset definition in the ruleset repository. The connection to the ruleset repository is configured when the RES is deployed to the Java EE server. During job execution, the connector acts as the remote EJB3 client and establishes connection to the EJB3 rule session component that must be deployed to the Java EE server on which the Rule Execution Server is deployed. When using this engine mode, ruleset location stage property specifies the path of the ruleset in the repository.
Note: For batch types of operations, the Core engine and J2SE RES XU modes generally provide for better performance than the J2EE RES XU mode because the connector exchanges Java objects with the JRules engine that runs in the same Java Virtual Machine as the connector. In the J2EE RES XU engine mode, the connector accesses the JRules engine that runs on the Java EE server through the remote EJB interface and the Java objects that they exchange need to be serialized and deserialized as part of the process which can incur a significant overhead.