org.drools.agent.KnowledgeAgent Maven / Gradle / Ivy
package org.drools.agent;
import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseFactory;
import org.drools.SystemEventListener;
import org.drools.io.Resource;
import org.drools.io.ResourceChangeScannerConfiguration;
import org.drools.io.ResourceFactory;
/**
*
* The KnowlegeAgent is created by the KnowlegeAgentFactory. It's role is to provide a cached
* KnowlegeBase and to update or rebuild this KnowlegeBase as the resources it uses are changed.
* The strategy for this is determined by the configuration given to the factory, but it is
* typically pull based using regular polling. We hope to add push based updates and rebuilds in future
* versions.
*
*
* The Follow example constructs an agent that will build a new KnowledgeBase from the files specified in the path String.
* It will poll those files every 30 seconds to see if they are updated. If new files are found it will construct a new
* KnowledgeBase, instead of updating the existing one, due to the "newInstance" set to "true" (however currently only the value of
* "true" is supported and is hard coded into the engine):
*
*
* // Set the interval on the ResourceChangeScannerService if you are to use it and default of 60s is not desirable.
* ResourceChangeScannerConfiguration sconf = ResourceFactory.getResourceChangeScannerService().newResourceChangeScannerConfiguration();
* sconf.setProperty( "drools.resource.scanner.interval",
* "30" ); // set the disk scanning interval to 30s, default is 60s
* ResourceFactory.getResourceChangeScannerService().configure( sconf );
*
* KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
*
* KnowledgeAgentConfiguration aconf = KnowledgeAgentFactory.newKnowledgeAgentConfiguration();
* aconf.setProperty( "drools.agent.scanDirectories",
* "true" ); // we want to scan directories, not just files, turning this on turns on file scanning
* aconf.setProperty( "drools.agent.newInstance",
* "true" ); // resource changes results in a new instance of the KnowledgeBase being built,
* // this cannot currently be set to false for incremental building
*
* KnowledgeAgent kagent = KnowledgeAgentFactory.newKnowledgeAgent( "test agent", // the name of the agent
* kbase, // the rulebase to use, the Agent will also monitor any exist knowledge definitions
* aconf );
* kagent.applyChangeSet( ResourceFactory.newUrlResource( url ) ); // resource to the change-set xml for the resources to add
*
*
* KnowledgeAgents can take a empty KnowledgeBase or a populated one. If a populated KnowledgeBase is provided, the KnowledgeAgent
* will iterate KnowledgeBase and subscribe to the Resource that it finds. While it is possible for the KnowledgeBuilder to build
* all resources found in a directory, that information is lost by the KnowledgeBuilder so those directories will not be continuously scanned.
* Only directories specified as part of the applyChangeSet(Resource) method are monitored.
*
* @see org.drools.agent.KnowledgeAgentFactory
* @see org.drools.agent.KnowledgeAgentConfiguration
*
*/
public interface KnowledgeAgent {
/**
*
* @return
* The name
*/
String getName();
/**
* Returns the cached KnowledgeBase
* @return
* The KnowledgeBase
*/
KnowledgeBase getKnowledgeBase();
void monitorResourceChangeEvents(boolean monitor);
void applyChangeSet(Resource resource);
void setSystemEventListener(SystemEventListener listener);
}