Drools动态加载规则文件

/** 
 * Tools for Drools 
 * @author kevin 
 * @version Date: 2009-7-7 Time: 10:34:58 
 */  
public class DroolsUtil {  
    private KnowledgeAgent kagent;  
    private static DroolsUtil instance;  
  
    /** 
     *  return the default agent with name "agent" and interval "5" 
     */  
    private DroolsUtil(){  
        this.kagent = getKnowledgeAgent("agent","5");  
    }  
  
    /** 
     * return the agent with the specified name and interval 
     * @param agentName The name of the agent 
     * @param interval The interval to scan resources 
     */  
    private DroolsUtil(String agentName,String interval){  
        this.kagent = getKnowledgeAgent(agentName,interval);  
    }  
  
    /** 
     * return the instance with default agent 
     * @return DroolsUtil's instance 
     */  
    public static DroolsUtil getInstance(){  
        if(instance == null){  
            instance = new DroolsUtil();  
        }  
        return instance;  
    }  
  
    /** 
     * return the instance with agent which is given specified name and  interval 
     * @param agentName The name of the agent 
     * @param interval The interval to scan resources 
     * @return DroolsUtil's instance 
     */  
    public static DroolsUtil getInstance(String agentName,String interval){  
        if(instance == null){  
           instance = new DroolsUtil(agentName,interval);  
        }  
        return instance;  
    }  
  
    /** 
     * Get the KnowledgeAgent and make it scan the resources per 5 seconds 
     * @param agentName The name of the agent 
     * @param interval The interval to scan resources 
     * @return KnowledgeAgent 
     */  
    public KnowledgeAgent getKnowledgeAgent(String agentName,String interval){  
        ResourceChangeScannerConfiguration sconf = ResourceFactory.getResourceChangeScannerService().newResourceChangeScannerConfiguration();  
        sconf.setProperty("drools.resource.scanner.interval",interval);  
        ResourceFactory.getResourceChangeScannerService().configure(sconf);  
        ResourceFactory.getResourceChangeScannerService().start();  
        ResourceFactory.getResourceChangeNotifierService().start();  
        KnowledgeAgentConfiguration aconf = KnowledgeAgentFactory.newKnowledgeAgentConfiguration();  
        aconf.setProperty("drools.agent.scanDirectories","true");  
        aconf.setProperty("drools.agent.newInstance","true");  
        KnowledgeAgent kagent = KnowledgeAgentFactory.newKnowledgeAgent(agentName,aconf);  
        kagent.applyChangeSet(ResourceFactory.newClassPathResource("resource.xml"));  
        return kagent;  
    }  
  
    /** 
     * Get the KnowledgeBase 
     * @return KnowledgeBase 
     */  
    public KnowledgeBase getKnowledgeBase(){  
        return kagent.getKnowledgeBase();  
    }  
  
    /** 
     * Get the StatefulKnowledgeSession 
     * @return StatefulKnowledgeSession 
     */  
    public StatefulKnowledgeSession getStatefulKnowledgeSession(){  
        return getKnowledgeBase().newStatefulKnowledgeSession();  
    }  
  
    /** 
     * Get the StatelessKnowledgeSession 
     * @return StatelessKnowledgeSession 
     */  
    public StatelessKnowledgeSession getStatelessKnowledgeSession(){  
        return getKnowledgeBase().newStatelessKnowledgeSession();  
    }  
      
}