16.4. KIE Deployment

16.4.1. KieRepository

When the contents of a KieFileSystem are successfully built, the resulting KieModule is automatically added to the KieRepository. The KieRepository is a singleton acting as a repository for all the available KieModules.
After this it is possible to create through the KieServices a new KieContainer for that KieModule using its ReleaseId. However, since in this case the KieFileSystem don't contain any pom.xml file (it is possible to add one using the KieFileSystem.writePomXML method), Kie cannot determine the ReleaseId of the KieModule and assign to it a default one. This default ReleaseId can be obtained from the KieRepository and used to identify the KieModule inside the KieRepository itself. The following example shows this whole process.

Example 16.11. Building the contents of a KieFileSystem and creating a KieContainer

import org.kie.api.KieServices;
import org.kie.api.KieServices.Factory;
import org.kie.api.builder.KieFileSystem;
import org.kie.api.builder.KieBuilder;
import org.kie.api.runtime.KieContainer;

KieServices kieServices = KieServices.Factory.get();
KieFileSystem kfs = ...
kieServices.newKieBuilder( kfs ).buildAll();
KieContainer kieContainer = kieServices.newKieContainer(kieServices.getRepository().getDefaultReleaseId());
At this point it is possible to get KieBases and create new KieSessions from this KieContainer exactly in the same way as in the case of a KieContainer created directly from the classpath.
It is a best practice to check the compilation results. The KieBuilder reports compilation results of 3 different severities: ERROR, WARNING and INFO. An ERROR indicates that the compilation of the project failed and in the case no KieModule is produced and nothing is added to the KieRepository. WARNING and INFO results can be ignored, but are available for inspection.

Example 16.12. Checking that a compilation didn't produce any error

import org.kie.api.builder.KieBuilder;
import org.kie.api.KieServices;

KieBuilder kieBuilder = kieServices.newKieBuilder( kfs ).buildAll();
assertEquals( 0, kieBuilder.getResults().getMessages( Message.Level.ERROR ).size() );

16.4.2. Session Modification

The KieBase is a repository of all the application's knowledge definitions. It will contain rules, processes, functions, and type models. The KieBase itself does not contain data; instead, sessions are created from the KieBase into which data can be inserted and from which process instances may be started. The KieBase can be obtained from the KieContainer containing the KieModule where the KieBase has been defined.
Sometimes, for instance in a OSGi environment, the KieBase needs to resolve types that are not in the default class loader. In this case it will be necessary to create a KieBaseConfiguration with an additional class loader and pass it to KieContainer when creating a new KieBase from it.

Example 16.13. Creating a new KieBase with a custom ClassLoader

import org.kie.api.KieServices;
import org.kie.api.KieServices.Factory;
import org.kie.api.KieBaseConfiguration;
import org.kie.api.KieBase;
import org.kie.api.runtime.KieContainer;

KieServices kieServices = KieServices.Factory.get();
KieBaseConfiguration kbaseConf = kieServices.newKieBaseConfiguration( null, MyType.class.getClassLoader() );
KieBase kbase = kieContainer.newKieBase( kbaseConf );
The KieBase creates and returns KieSession objects, and it may optionally keep references to those. When KieBase modifications occur those modifications are applied against the data in the sessions. This reference is a weak reference and it is also optional, which is controlled by a boolean flag.

Note

If you are using the WebLogic Server, then you need to be aware of how the WebLogic Server finds and loads application class files at run time. When using a non-exploded WAR deployment, WebLogic packs the contents of WEB-INF/classes into WEB-INF/lib/_wl_cls_gen.jar. So when you use KIE-Spring to create KieBase and KieSession from resources stored under WEB-INF/classes, KIE-Spring fails to locate these resources. For this reason, the recommended deployment method in WebLogic, is to use the exploded archives contained within the product's ZIP file.

16.4.3. KieScanner

The KieScanner allows continuous monitoring of your Maven repository to check whether a new release of a KIE project has been installed. A new release is deployed in the KieContainer wrapping that project. The use of the KieScanner requires kie-ci.jar to be on the classpath.
A KieScanner can be registered on a KieContainer as in the following example.

Example 16.14. Registering and starting a KieScanner on a KieContainer

import org.kie.api.KieServices;
import org.kie.api.builder.ReleaseId;
import org.kie.api.runtime.KieContainer;
import org.kie.api.builder.KieScanner;

...

KieServices kieServices = KieServices.Factory.get();
ReleaseId releaseId = kieServices.newReleaseId( "org.acme", "myartifact", "1.0-SNAPSHOT" );
KieContainer kContainer = kieServices.newKieContainer( releaseId );
KieScanner kScanner = kieServices.newKieScanner( kContainer );

// Start the KieScanner polling the Maven repository every 10 seconds
kScanner.start( 10000L );
In this example the KieScanner is configured to run with a fixed time interval, but it is also possible to run it on demand by invoking the scanNow() method on it. If the KieScanner finds in the Maven repository an updated version of the KIE project used by that KieContainer it automatically downloads the new version and triggers an incremental build of the new project. From this moment all the new KieBases and KieSessions created from that KieContainer will use the new project version.

Maven Settings

Since KieScanner relies on Maven, Maven should be configured with the correct updatePolicy of always as shown in the following example: 
<profile>
      <id>guvnor-m2-repo</id>
      <repositories>
        <repository>
          <id>guvnor-m2-repo</id>
          <name>BRMS Repository</name>
          <url>http://10.10.10.10:8080/business-central/maven2/</url>
          <layout>default</layout>
          <releases>
            <enabled>true</enabled>
            <updatePolicy>always</updatePolicy>
          </releases>
          <snapshots>
            <enabled>true</enabled>
            <updatePolicy>always</updatePolicy>
          </snapshots>
        </repository>
      </repositories>
    </profile>