RCP中视图之间的通讯[OSGI-EventAdmin]


我在Eclipse新闻组中经常看到讨论视图之间通信的问题，他们经常要面对状态改变之后的同步问题(通常的做法是使用ISelectionService)，看来大家对OSGI EventAdmin服务不是很了解,这是一个采用发布订阅模式的事件系统,可以很轻松的应用到您的RCP程序中。
   1、安装
    首先将org.eclipse.osgi.services和org.eclipse.equinox.event添加到工程的依赖项中。
   
   2、发布事件
   public class SenderView extends ViewPart {   public static final String ID = "viewcommunication.views.SenderView";
  private Button b;
  public void createPartControl(Composite parent) {
    parent.setLayout(new GridLayout());
    b = new Button(parent, SWT.PUSH);
    b.setText("Send Event");
    b.addSelectionListener(new SelectionAdapter() {
      @Override
      public void widgetSelected(SelectionEvent e) {
        BundleContext ctx = FrameworkUtil.getBundle(SenderView.class).getBundleContext();
        ServiceReference<EventAdmin> ref = ctx.getServiceReference(EventAdmin.class);
        EventAdmin eventAdmin = ctx.getService(ref);
        Map<String,Object> properties = new HashMap<String, Object>();
        properties.put("DATA", new Date());
        Event event = new Event("viewcommunication/syncEvent", properties);
        eventAdmin.sendEvent(event);
        event = new Event("viewcommunication/asyncEvent", properties);
        eventAdmin.postEvent(event);
      }
    });
  }
  public void setFocus() {
    b.setFocus();
  }
}
      3、订阅事件
 1 public class ReceiverView extends ViewPart {
 2   private TableViewer viewer;
 3 
 4   @Override
 5   public void createPartControl(final Composite parent) {
 6     parent.setLayout(new FillLayout());
 7     viewer = new TableViewer(parent);
 8     viewer.getTable().setHeaderVisible(true);
 9     viewer.getTable().setLinesVisible(true);
10     viewer.setLabelProvider(new ColumnLabelProvider() {
11       @Override
12       public String getText(Object element) {
13         return DateFormat.getDateTimeInstance().format(element);
14       }
15     });
16 
17     BundleContext ctx = FrameworkUtil.getBundle(ReceiverView.class).getBundleContext();
18     EventHandler handler = new EventHandler() {
19       public void handleEvent(final Event event) {
20         if( parent.getDisplay().getThread() == Thread.currentThread() ) {
21           viewer.add(event.getProperty("DATA"));
22         } else {
23           parent.getDisplay().syncExec(new Runnable() {
24             public void run() {
25               viewer.add(event.getProperty("DATA"));
26             }
27           });
28         }
29       }
30     };
31 
32     Dictionary<String,String> properties = new Hashtable<String, String>();
33     properties.put(EventConstants.EVENT_TOPIC, "viewcommunication/*");
34     ctx.registerService(EventHandler.class, handler, properties);
35   }
36 
37   @Override
38   public void setFocus() {
39     viewer.getTable().setFocus();
40   }
41 }
42 

不是很复杂,对吧,起码降低了耦合度。

补充：软件开发 , Java ,