eclipse中扩展点的添加和删除

ExtensionTracker是IExtensionTracker的实现，用于跟踪插件是否为活动状态，由eclipse官方提供的工具类，eclipse的官方UI组件对IExtensionTracker有自己的实现。如下为例子：

public void start(BundleContext context) throws Exception { 
   IExtensionRegistry reg = Platform.getExtensionRegistry(); 
   IExtensionPoint ep =  
  reg.getExtensionPoint(MY_EXTENSION_POINT_ID); 
   tracker = new ExtensionTracker(reg); 
   IFilter filter =  
  ExtensionTracker.createExtensionPointFilter(ep); 
   tracker.registerHandler(this, filter); 
   IExtension[] extensions = ep.getExtensions(); 
   for (int i = 0; i < extensions.length; ++i) 
  addExtension(tracker, extensions); 
} 

 

public void stop(BundleContext context) throws Exception { 
   if (tracker != null) { 
  tracker.close(); 
  tracker = null; 
  } 
} 

 

public void addExtension(IExtensionTracker tracker, 
  IExtension extension) { 
   IConfigurationElement[] configs =  
  extension.getConfigurationElements(); 
   for (int i = 0; i < configs.length; ++i) { 
  // use configuration properties for something 
  // ... 
  MyDelegate delegate = (MyDelegate) 
 configs.createExecutableExtension(CLASS_ATTR); 
  // do what you need to do 
  // ... 
  delegates.add(delegate); 
  // register association between object and extension 
  // with the tracker 
  tracker.registerObject(extension, delegate, 
 IExtensionTracker.REF_WEAK); 
   } 
} 

 

public void removeExtension(IExtension extension, 
Object[] objects) { 
   // stop using objects associated with 
   // the removed extension 
   for (int i = 0; i < objects.length; ++i) 
  delegates.remove(objects); 
}