Develop Reference

How to enable / disable action in Netbeans Platform

I have spent almost three days trying to do a simple enable / disable of Actions in the netbeans plaform, something that I though was going to be simple, and should be a common feature is more complex than I thought.
At the begging I tried to see if there was an setEnable() method on the default actions generated and to my surprise there is not. Then I started looking into that and I found that most common method to do it was setting a conditionally enabled action (which depends on a Cookie class), So I figured out how to add a fake class to the Lookup so it gets enabled and disabled, I did it the following way. To test it out I added the following code to another action which should enable or disable the second one.
private final PlottingStarted plottingStarted = new PlottingStarted();
#Override
public void actionPerformed(ActionEvent e) {
// TODO implement action body
if (Lookup.getDefault().lookup(PlottingStarted.class) == null) {
ic.add(plottingStarted);
}else{
ic.remove(plottingStarted);
}
So PlottingStarted is a fake object I created which only purpose is being in the lookup to disable or enable the action.
For some reason it did not do anything at all an the Action was always disabled. I tried many things and finally I gave up.
Then I tried a different approach and was using AbstractActions which do have the setEnabled() ability.
To retrieve the action I based myself on one the Geertjan blogs and I created the following method
public Action findAction(String actionName) {
FileObject myActionsFolder = FileUtil.getConfigFile("Actions/RealTimeViewer");
if (myActionsFolder != null){
FileObject[] myActionsFolderKids = myActionsFolder.getChildren();
for (FileObject fileObject : myActionsFolderKids) {
//Probably want to make this more robust,
//but the point is that here we find a particular Action:
if (fileObject.getName().contains(actionName)) {
try {
DataObject dob = DataObject.find(fileObject);
InstanceCookie ic = dob.getLookup().lookup(InstanceCookie.class);
if (ic != null) {
Object instance = ic.instanceCreate();
if (instance instanceof Action) {
Action a = (Action) instance;
return a;
}
}
} catch (Exception e) {
ErrorManager.getDefault().notify(ErrorManager.WARNING, e);
return null;
}
}
}
}
return null;
}
This method worked perfectly and I was able to retrieve the action and call its setEnabled() method. Unfortunately no matter why I did the Action was always enabled.
Reading some literature I found that I should add the following to the registration of the action "lazy = false" and finally I was able to enable and disable the Action... But off course the default registration is lost and I have no Icons and Names.
Now I decided to post again because I cannot believe that it need to be that complex, there must be a way to do it easier. The only thing I need is to have a PLAY / STOP functionality, when PLAY is enabled STOP is disabled and vice-versa.

I have not done this myself but it seems to be covered in Chapter 5.1.2.1 "Complex Enablement" of the book "Netbeans Platform for Beginners". https://leanpub.com/nbp4beginners
The book is not free but the corresponding code sample is available on
github. https://github.com/walternyland/nbp4beginners/tree/master/chapters/ch05/5.1.2.1 He extends AbstractAction overrides the resultChanged method and uses super.setEnabled().
#ActionID(id = "org.carsales.evaluator.EvaluateCarAction1", category = "Car")
#ActionRegistration(displayName = "not-used", lazy = false)
public class EvaluateCarAction extends AbstractAction
implements ContextAwareAction, LookupListener {
// ...
#Override
public void resultChanged(LookupEvent le) {
//Optionally, check if the property is set to the value you're interested in
//prior to enabling the Action.
super.setEnabled(result.allInstances().size() > 0);
}

Thanks to everybody for your responses. I finally got it to work by extending AbstractAction, it seems that even if you register "lazy = false" some of the registration is still being done by the platform and you just need some minor tweaking in the Action constructor. The final result was
#ActionID(
category = "RealTimeViewer",
id = "main.java.com.graph.actions.StopPlotting"
)
#ActionRegistration(
//iconBase = "main/java/com/graph/images/stop-plotting-24x24.png",
displayName = "#CTL_StopPlotting",
lazy = false
)
#ActionReference(path = "Toolbars/RealTimeViewer", position = 600)
#Messages("CTL_StopPlotting=Stop Plotting")
public final class StopPlotting extends AbstractAction{
private static final String ICON = "main/java/com/dacsys/cna/core/graph/images/stop-plotting-24x24.png";
public StopPlotting() {
putValue(SMALL_ICON, ImageUtilities.loadImageIcon(ICON, false));
putValue(NAME, Bundle.CTL_StopPlotting());
this.setEnabled(false);
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO implement action body
Action a = new ActionsHelper().findAction("StartPlotting");
if (a != null){
if (a != null){
if (a.isEnabled()){
a.setEnabled(false);
this.setEnabled(true);
}else{
a.setEnabled(true);
this.setEnabled(false);
}
}
}
}
}

How to handle close tab in eclipse RCP 4

I want make a validation when pulse close button of tab in eclipse RCP 4 application and if some validation fails then prevent de close.

If you don't want to use part.setDirty(true) together with an ISaveHandler like greg-449 montioned, you could listen to the model events and correct things there. Something in the direction of this:
public class PreventCloseAddon {
#PostConstruct
public void init(final IEventBroker eventBroker, final EPartService partService) {
EventHandler tbrHandler = new EventHandler() {
#Override
public void handleEvent(Event event) {
if (!UIEvents.isSET(event))
return;
Object element = event.getProperty(UIEvents.EventTags.ELEMENT);
if (element instanceof MPart) {
MPart part = (MPart) element;
if (!part.isToBeRendered()) {
// ... validate here ...
part.setToBeRendered(true);
partService.activate(part);
}
}
}
};
eventBroker.subscribe(UIEvents.UIElement.TOPIC_TOBERENDERED, tbrHandler);
}
}
You should be aware that the part will be rendered again with this code.

Eclipse plugin dev - How to add hyperlink on FieldEditorPreferencePage

I was searching for way to add link in Eclipse Preferences page. I quickly found How to create a hyperlink in Eclipse plugin preferences page? . The solution however does not fit
public class GradlePreferencePage extends FieldEditorPreferencePage implements IWorkbenchPreferencePage {
...
final Link link = new Link(getFieldEditorParent(), SWT.NONE);
link.setText("link");
link.setLayoutData(getFieldEditorParent().getLayout());
link.addSelectionListener(new SelectionAdapter() {
#Override
public void widgetSelected(final SelectionEvent event)
{
int style = IWorkbenchBrowserSupport.AS_EDITOR | IWorkbenchBrowserSupport.LOCATION_BAR | IWorkbenchBrowserSupport.NAVIGATION_BAR | IWorkbenchBrowserSupport.STATUS;
IWebBrowser browser;
try {
browser = WorkbenchBrowserSupport.getInstance().createBrowser(style, "NodeclipsePluginsListID", "NodeclipsePluginsList", "Nodeclipse Plugins List");
browser.openURL(new URL("http://www.nodeclipse.org/updates"));
} catch (PartInitException e) {
e.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
}
}
});
However I cannot addField(link); as
The method addField(FieldEditor) in the type FieldEditorPreferencePage is not applicable for the arguments (Link)
Is there as way to add link in FieldEditorPreferencePage ? e.g. to compose FieldEditor from several part (label, link, Text) ?

You don't need to call addField to just add a normal control to the field editor preference page. The code you have is sufficient. addField is only needed for FieldEditor derived classes.
Update: Your setLayoutData is incorrect, use something like:
link.setLayoutData(new GridData(SWT.FILL, SWT.TOP, false, false, 3, 1));
You may have to adjust the number of columns depending on the rest of your page.

Eclipse IDE - Perspective is cached and changes has no any effect

I have created new Eclipse IDE (plugin project, Eclipse Kepler, rel. 1) with default template of mail client.
After the first run of the app, the Perspective is stored and remembered (somewhere?) and any changes to Perspective.java has no any effect! Even if I delete the content of createInitialLayout(IPageLayout layout) from the Perspective.java, everything is restored again.
BTW: adding this code to ApplicationWorkbenchAdvisor.java didnt help:
#Override
public void initialize(IWorkbenchConfigurer configurer) {
super.initialize(configurer);
configurer.setSaveAndRestore(false);
}
How can I force the app to not to remmeber the layout?

You could call IWorkbenchPage.resetPerspective() to reinitialize the perspective, perhaps in the WorkbenchWindowAdvisor.postWindowRestore() method.

Thank you. I have added the following code to menu. Now I can reset perspective whenever I need.
public class ApplicationActionBarAdvisor extends ActionBarAdvisor {
private IWorkbenchAction resetPerspectiveAction;
#Override
protected void makeActions(IWorkbenchWindow window) {
// ...
// create and register the actions
resetPerspectiveAction = ActionFactory.RESET_PERSPECTIVE.create(window);
register(resetPerspectiveAction);
// ...
}
#Override
protected void fillMenuBar(IMenuManager menuBar) {
// ...
// create and fill the window menu
MenuManager windowMenu = new MenuManager("&Window", WorkbenchActionConstants.M_WINDOW);
menuBar.add(windowMenu);
windowMenu.add(resetPerspectiveAction);
// ...
}
}

Disable back button in GWT

Is there a way to disable the Back button in a browser (basically clearing the History token stack) in GWT? Once I browse to a certain page in my application I want to make sure that the user can't use the back button to go back, but only be able to use links on the page to navigate the site.

You cannot disable a button just intercept it and change its return to something the browser does not understand.
This removes the history:
Window.addWindowClosingHandler(new ClosingHandler() {
#Override
public void onWindowClosing(ClosingEvent event) {
event.setMessage("My program");
}
});
To understand it see: http://groups.google.com/group/google-web-toolkit/browse_thread/thread/8b2a7ddad5a47af8/154ec7934eb6be42?lnk=gst&q=disable+back+button#154ec7934eb6be42
However, I would recommend not doing this because your it goes against good UI practices. Instead you should figure out a way that the back button does not cause a problem with your code.

Call the method below in the onModuleLoad().
private void setupHistory() {
final String initToken = History.getToken();
if (initToken.length() == 0) {
History.newItem("main");
}
// Add history listener
HandlerRegistration historyHandlerRegistration = History.addValueChangeHandler(new ValueChangeHandler() {
#Override
public void onValueChange(ValueChangeEvent event) {
String token = event.getValue();
if (initToken.equals(token)) {
History.newItem(initToken);
}
}
});
// Now that we've setup our listener, fire the initial history state.
History.fireCurrentHistoryState();
Window.addWindowClosingHandler(new ClosingHandler() {
boolean reloading = false;
#Override
public void onWindowClosing(ClosingEvent event) {
if (!reloading) {
String userAgent = Window.Navigator.getUserAgent();
if (userAgent.contains("MSIE")) {
if (!Window.confirm("Do you really want to exit?")) {
reloading = true;
Window.Location.reload(); // For IE
}
}
else {
event.setMessage("My App"); // For other browser
}
}
}
});
}

I found a way to make GWT ignore the back-button: Just add historyitem x if no historyitem was set and do nothing on x.
set a historyitem on startup
History.newItem("x")
in the ValueChangeHandler of History add the following:
String historyToken = event.getValue();
if (!historyToken.equals("x"))
History.newItem("x");

Window.addWindowClosingHandler(new ClosingHandler() {
#Override
public void onWindowClosing(ClosingEvent event) {
event.setMessage("My program");
}
});
That is not a fool proof solution. In fire fox I can press the back button and the onWindowClosing method is never invoked. The reason is that I have used History.newItem() and since history exists the back button or backspace buttons simply navigate through the browser history.
So....fix that :)

Put this in your index.html file:
window.open('html page(For example trial.html)', 'Name of the desired site', width='whatever you want',height='whatever you want', centerscreen=yes, menubar=no,toolbar=no,location=no,
personalbar=no, directories=no,status=no, resizable=yes, dependent=no, titlebar=no,dialog=no');