Communication between views in RCP [OSGI-EventAdmin]

I often see communication between views in the Eclipse news group. They often have to face the synchronization problem after the status changes (the common practice is to use ISelectionService ), it seems that you do not know much about the OSGI EventAdmin service. This is an event system that uses the publish/subscribe mode and can be easily applied to your RCP program.

1. Installation
Add org. eclipse. osgi. services and org. eclipse. equinox. event to the project dependencies.

2. Release events
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. subscribe to events
1 public class ReceiverView extends ViewPart {
2 private TableViewer;
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

It's not very complicated, right? At least it reduces coupling.