Thread: [Springframework-rcp-dev] [Desktop] @Command style

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I've fleshed out my prototype a little bit more in the "adi-based-views"
branch.  Here's the sample application in its entirety (minus imports and
the like).  It's only 4 classes (one bootstrap, one view, two commands) and
a config file, but it show the ideas reasonably well:

----------

public class App {
  public static void main(String[] args) {
    ClassPathXmlApplicationContext ctx = new
ClassPathXmlApplicationContext("classpath:/META-INF/spring/simple-adi-context.xml");
    final Application app =
(Application)ctx.getBeansOfType(Application.class).values().toArray()[0];
    app.start(new String[0]);
  }
}

<beans>
  <context:component-scan base-package="org.springframework.desktop.samples"

scope-resolver="org.springframework.desktop.stereotype.support.DesktopAnnotationScopeMetadataResolver"
/>

  <bean class="org.springframework.desktop.core.support.DefaultApplication"
p:startingWindowName="theWindow" />

  <bean name="theWindow"
class="org.springframework.desktop.core.support.DefaultApplicationWindow"
    p:startingViewName="sampleView" />
</beans>

@View
public class SampleView extends AbstractApplicationWindowView {
  protected JComponent createComponent() {
    JPanel panel = new JPanel();
    panel.add(createButton("noarg"));
    panel.add(createButton("myViewCommand"));
    return panel;
  }

  protected List<String> getCommandNames() {
    return Arrays.asList("noarg", "myViewCommand");
  }
}

@Command("noarg")
public class MyStandAloneCommand {
  @Invoker
  public void showDialog() {
    JOptionPane.showMessageDialog(null, "Stand Alone");
  }
}

@Command
public class MyViewCommand {
  @Invoker
  public void showDialog(SampleView view) {
    JOptionPane.showMessageDialog(view.getComponent(), "This is for " +
view);
  }
}

------

That's it.  Some things to be sure to notice:

  * The XML only contains two definitions (besides the component-scan): the
Application and starting ApplicationWindow.  And that is only because I
wanted to use default implementations but configure them externally.
Everything else is wired up by the component-scan.

  * Views and Commands are created using "prototype" scoping from the
ApplicationContext.  The "DesktopAnnotationScopeMetadataResolver" in the
config is what handles that for us so the user doesn't need to put a
@Scope("prototype") at the top of all of their classes.  (Obviously we need
to hide this behind a custom namespace element.)
      - It's currently set up so that ApplicationWindows own Views which own
Commands, and ApplicationWindows own Commands.  This effectively gives us
"window" and "view" scopes without the complicated event processing and
ThreadLocal magic that would be needed to do custom Scope implementations.

  * The view merely has to say what commands it needs and they are available
to it.  In a more realistic application you'd want to do name-spacing of
some sort...

  * The super nifty part is that commands don't have to extend or implement
anything as long as they are annotated with @Command and @Invoker, using the
same kind of adapter-pattern magic that SpringMVC does when you use
@Controller and @RequestMapping.  Methods that are marked as @Invoker get
the same kind of "well known types" support that @RequestMapping methods do,
so if you want the View, put it in the signature and it will automatically
be handed to you.  (Note as well that it's not just some generic View --
static/strong typing applies so I can ask for specifically SampleView in the
signature.) If you don't care, don't have it in the signature.  Right now
only Views are supported, but there's nothing stopping us from adding other
"well known types" like ApplicationWindow, JFrame, JDialog, SecurityContext,
etc.  (A great place to see the "magic" happen for the commands and how it
works is in CommandAnnotationAdapterTests.)

Hopefully that helps show what some of the possibilities are.  Please let me
know if you have any questions/comments.

-Jim Moore

Thread: [Springframework-rcp-dev] [Desktop] @Command style

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