/**
    * Copyright 2005-2011 The Kuali Foundation
    *
    * Licensed under the Educational Community License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.opensource.org/licenses/ecl2.php
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.kuali.rice.krms.framework.engine;
  
  import javax.swing.event.EventListenerList;
  
  import org.kuali.rice.krms.api.engine.ExecutionEnvironment;
  import org.kuali.rice.krms.api.engine.ExecutionFlag;
  import org.kuali.rice.krms.api.engine.ResultEvent;
  import org.kuali.rice.krms.framework.engine.result.EngineResultListener;
  import org.kuali.rice.krms.framework.engine.result.Log4jResultListener;
  import org.kuali.rice.krms.framework.engine.result.ResultListener;
  
  public class ResultLogger {
  	private EventListenerList listenerList = new EventListenerList();
  	
  	private ResultLogger(){}
  	
  	/*using inner class provides thread safety.	 */
  	private static class KRMSLoggerLoader{
  		private static final ResultLogger INSTANCE = new ResultLogger();
  	}
  	
  	public static ResultLogger getInstance(){
  		return KRMSLoggerLoader.INSTANCE;
  	}
  	
  	public void addListener(ResultListener l) {
  		listenerList.add(ResultListener.class, l);		
  	}
  	
  	public void removeListener(ResultListener l){
  		listenerList.remove(ResultListener.class, l);
  	}
  
  	public void logResult(ResultEvent event){
  		if (isEnabled(event.getEnvironment())){
  			// fire event to listeners
  			Object[] listeners = listenerList.getListenerList();
  			for (int i=1; i<listeners.length; i+=2){
  				((ResultListener) listeners[i]).handleEvent(event);
  			}
  		}
  	}
  
  	public boolean isEnabled(ExecutionEnvironment environment){
  	    return (
  	            environment != null 
  	            && environment.getExecutionOptions() != null 
  	            && environment.getExecutionOptions().getFlag(ExecutionFlag.LOG_EXECUTION)
  	    );
  	}
  }