/**
    * Copyright By Grandsoft Company Limited.  
    * 2013-9-12 上午03:23:51
    */
   package gboat2.approveflow.service;
   
   import gboat2.approveflow.Activator;
   
   import java.util.LinkedList;
  import java.util.List;
  
  import org.apache.log4j.Logger;
  import org.osgi.framework.BundleContext;
  import org.osgi.framework.Filter;
  import org.osgi.framework.InvalidSyntaxException;
  import org.osgi.framework.ServiceReference;
  import org.osgi.util.tracker.ServiceTracker;
  
  
  /**
   * 
   * IApproveFlowNOdeChecker的注册类
   * @author lysming
   * @since jdk1.6
   * @date 2013-9-12
   *  
   */
  
  public class ApproveFlowNodeCheckerHolder {
  	ServiceTracker exitActionTracker;
  	
  	private static Logger logger = Logger.getLogger(ApproveFlowNodeCheckerHolder.class);
  	
  	private List<IApproveFlowNodeChecker> checkers = new LinkedList<IApproveFlowNodeChecker>();
  	
  	public ApproveFlowNodeCheckerHolder(){
  		BundleContext context = Activator.LOCAL_BUNDLE.getBundleContext();
  		try {
  			Filter exitFilter = context.createFilter("(objectClass=gboat2.approveflow.service.IApproveFlowNodeChecker)");
  			exitActionTracker = new ServiceTracker(Activator.LOCAL_BUNDLE.getBundleContext(),exitFilter,null){
  				@Override
  				public Object addingService(ServiceReference refer){
  					IApproveFlowNodeChecker checker = (IApproveFlowNodeChecker)context.getService(refer);
  					registExitActionHandler(checker);
  					return checker;
  				}
  				
  				@Override
  				public void remove(ServiceReference refer){
  					IApproveFlowNodeChecker checker = (IApproveFlowNodeChecker)context.getService(refer);
  					unRegistExitActionHandler(checker);
  					super.remove(refer);
  				}
  			};
  			exitActionTracker.open();
  		} catch (InvalidSyntaxException e) {
  			logger.error(e);
  		}
  	}
  	
  	private synchronized void registExitActionHandler(IApproveFlowNodeChecker checker) {
  		checkers.add(checker);
  	}
  	
  	private synchronized void unRegistExitActionHandler(IApproveFlowNodeChecker checker) {
  		checkers.remove(checker);
  	}
  	
  	public List<IApproveFlowNodeChecker> getNodeCheckers(){
  		return checkers;
  	}
  }