how to pass object parameters in command?

Question

I created an eclipse-rcp's project's plugin.xml with a new command with a parameter.

 ArrayList<parameterization> parameters = new ArrayList<parameterization>();
 IParameter iparam;

 //get the command from plugin.xml
IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
 ICommandService cmdService =     (ICommandService)window.getService(ICommandService.class);
 Command cmd = cmdService.getCommand("org.ipiel.demo.commands.click");

//get the parameter
iparam = cmd.getParameter("org.ipiel.demo.commands.click.paramenter1");
Parameterization params = new Parameterization(iparam, "commandValue");
parameters.add(params);

//build the parameterized command
 ParameterizedCommand pc = new ParameterizedCommand(cmd, parameters.toArray(new       Parameterization[parameters.size()]));

//execute the command
 IHandlerService handlerService = (IHandlerService)window.getService(IHandlerService.class);
handlerService.executeCommand(pc, null);

I tried this example to pass parameters and it worked.

The issue in this example that I could pass only parameters of type String. ( because Parameterization )

I want to pass parameter of hash map and in general to pass any object.

I tried this code

     IServiceLocator serviceLocator = PlatformUI.getWorkbench();
    ICommandService commandService = (ICommandService)      serviceLocator.getService(ICommandService.class);




    ExecutionEvent executionEvent = new ExecutionEvent(cmd, paramArray, null, null);
    cmd.executeWithChecks(executionEvent);

but it didn't work the parameters didn't move ( it was null)

Could you please help to to move object as parameter in command ?

Answer 1

Since it would get confusing to add another solution to my first answer, I'll provide another one for a second solution. The choices I gave were " A) use the selected object of the "Execution Event" (examine that, it contains a lot of infos). B) you can use AbstractSourceProvider, so you can pass your object to the application context."

A) can be used in your Handler if your object is the selection of a Structured Object like a Tree:

MyObject p = (MyObject) ((IStructuredSelection) HandlerUtil.getCurrentSelection(event)).getFirstElement();

B) The usage of a Source provider is a bit more tricky. The main idea is, that you add your object to the application context. The important snippets for Eclipse 3.x from a project that I set up after I read this blog (note: it is in german and the example it provides doesn't work): In your plugin.xml add:

  <extension point="org.eclipse.ui.services">
  <sourceProvider
        provider="com.voo.example.sourceprovider.PersonSourceProvider">
     <variable
           name="com.voo.example.sourceprovider.currentPerson"
           priorityLevel="activePartId">
     </variable>
  </sourceProvider>

Set up your own SourceProvider. Calling the "getCurrentState" you can get the variable (your Person object in this case) of that SourceProvider:

public class PersonSourceProvider extends AbstractSourceProvider{

/** This is the variable that is used as reference to the SourceProvider
 */
public static final String PERSON_ID = "com.voo.example.sourceprovider.currentPerson";
private Person currentPerson;

public PersonSourceProvider() {

}

@Override
public void dispose() {
    currentPerson = null;
}

**/**
 * Used to get the Status of the source from the framework
 */
@Override
public Map<String, Person> getCurrentState() {
    Map<String, Person> personMap = new HashMap<String, Person>();
    personMap.put(PERSON_ID, currentPerson);
    return personMap;
}**

@Override
public String[] getProvidedSourceNames() {
    return new String[]{PERSON_ID};
}

public void personChanged(Person p){
    if (this.currentPerson != null && this.currentPerson.equals(p)){
        return;
    }

    this.currentPerson = p;
    fireSourceChanged(ISources.ACTIVE_PART_ID, PERSON_ID, this.currentPerson);
}

}

In your View you register to the SourceProvider and set the Object to the object you want to transfer to your Handler.

public void createPartControl(Composite parent) {

    viewer = new TreeViewer(parent);
    viewer.setLabelProvider(new ViewLabelProvider());
    viewer.setContentProvider(new ViewContentProvider());
    viewer.setInput(rootPerson);
    getSite().setSelectionProvider(viewer);
    viewer.addSelectionChangedListener(new ISelectionChangedListener() {
        @Override
        public void selectionChanged(SelectionChangedEvent event) {
            Person p = null;
            if (event.getSelection() instanceof TreeSelection) {
                TreeSelection selection = (TreeSelection) event.getSelection();
                if (selection.getFirstElement() instanceof Person) {
                    p = (Person) selection.getFirstElement();
                }
            }
            if (p==null) {
                return;
            }
            IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
            ISourceProviderService service = (ISourceProviderService) window.getService(ISourceProviderService.class);
            PersonSourceProvider sourceProvider = (PersonSourceProvider) service.getSourceProvider(PersonSourceProvider.PERSON_ID);
            sourceProvider.personChanged(p);
        }
    });
}

And in your Handler you can just call the PersonSourceProvider#getCurrentState to get your Objects back.

Advantage of this method is, that you can use the Objectd anywhere you want. E.g. you can even set up a PropertyTester to enable/disable UI elements according to the currently selected Object.