Eclipse (XText) SelectionListener registration - java

I have implemented a view which shall register itself as listner for changes in the XText editor and related outline. To this end I am adding this line
PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().addSelectionListener(this);
in the createPartControl method of the view (which implements the ISelectionListener interface). In the selectionChanged method I therefore check whether the selection is a ITextSelection, the case in which it comes from the XTextEditor, or an IStructuredSelection, the case in which it come sfrom the Outline.
The problem is that, doing so, when I start Eclipse the outline is said to be "unavailable". If I click on the outline it is refreshed, the contents are shown and the listening view correctly updated.
What am I doing wrong and what should I do to avoid the initial "unavailability" of the outline?

I have been recently faced with this exact problem and have solved it by implementing IPartListener2 in the class that extends ViewPart then adding a part listener in the createPartcontrol method like this :
getSite().getWorkbenchWindow().getPartService().addPartListener(this);
Now by using something like this in your partOpened method (that has to be implemented before you can actually use the part listener you will get the view contents to be avaiable initially :
public void partOpened(IWorkbenchPartReference partRef) {
if(partRef.getPage().getActiveEditor() instanceof XtextEditor) {
somepart=partRef.getPage().getActiveEditor();
final XtextEditor editor = (XtextEditor)somepart;
final IXtextDocument document = editor.getDocument();
document.readOnly(new IUnitOfWork.Void<XtextResource>(){
public void process (XtextResource resource) throws Exception {
IParseResult parseResult = resource.getParseResult();
if(parseResult ==null)
return;
CompositeNode rootNode=(CompositeNode) parseResult.getRootNode();
LeafNode node = (LeafNode)NodeModelUtils.findLeafNodeAtOffset(rootNode, 0);
EObject object =NodeModelUtils.findActualSemanticObjectFor(node);
view.setInput(object);
}
});
}
}
this will make the view you're implementing get it's contents when you activate the XtextEditor (that is specific to your DSL).
In order to make the view change contents in real time as you change anything in the file active in the editor you should implement an IDocumentListener and override the DocumentChanged method. If you do this you won't be dependant on the SelectionListener anymore because the view should update automatically when something changes in your document
Hope this helps!

Related

Get TreeViewer in RCP from another Plugin

I'm working at a Plugin for a Eclipse-RCP. There is another Plugin with a TreeViewer and I want to select an Item from my Plugin. I don't know how to get access it, is this even possible?
I think can get the correct view with:
IViewReference home;
IViewReference [] viewRefs = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().getViewReferences();
for (int i = 0; i < viewRefs.length; i++) {
if(viewRefs[i].getId()==myid){
home = viewRefs[i];
break;
}
}
But home is not a TreeViewer and I cant cast it. How can I get the TreeViewer?
home.getTreeViewer() //Doesn't work cause of casting issues
I am a newbie to rcp, so I would be nice for some explanation.
You need to find your view using:
IWorkbenchPage page = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
IViewPart viewPart = page.findView("your view id");
You can then cast the view part to your view class and call a method that you write on that class:
if (viewPart != null) {
MyViewClass myViewPart = (MyViewClass)viewPart;
myViewPart.getTreeViewer();
}
where MyViewClass is your ViewPart class. You will have to write the getTreeViewer method.
If the view is not currently open you can use showView:
viewPart = page.showView("your view id");
You have to cast home to the type of your other view. Then you can get the TreeViewer.
You can find the ViewPart directly from your active IWorkbenchPage using IWorkbenchPage#findView(java.lang.String).
If you have the object you want to be selected, get the View's Site, get the Site's selection provider, and then tell the selection provider what should be selected (with a StructuredSelection instance containing the object). This only works if the tree, or whatever is in the part (you shouldn't have to care or know that it's a tree), actually contains the object that you're telling it to select.

Eclipse 4 RCP Editor using SourceViewer Undo and Redo operations are not working

I'm creating an editor using 'SourceViewer'. Given below is the code snippet from my '#PostConstruct' method.
// viewer is my SourceViewer instance
viewer = new SourceViewer(parent,verticalRuler, styles);
IUndoManager undoManager = new TextViewerUndoManager(25);
undoManager.connect(viewer);
viewer.setUndoManager(undoManager);
Even though a default 'TextViewerUndoManager' associated with 'SourceViewer'. Ctrl+Z and Ctrl+Y is not working.
Another alternative that I tried is to override the 'IUndoManager getUndoManager(ISourceViewer sourceViewer)' of 'SourceViewerConfiguration' subclass and return a 'TextViewerUndoManager'. This approach also doesn't give the desired result.
Kindly let me know what I'm missing in the above approaches.
It is normally the SourceViewerConfiguration that provides the Undo manager, the SourceViewer expects this and will set up the manager from that. The defaults already set up TextViewerUndoManager.
In an e4 application you do not get any default key bindings, commands or handlers so you will have to set up all these to make use of the undo manager.
In your application model declare Commands for undo and redo.
Declare key bindings for Ctrl+Z and Ctrl+Y specifying your commands. You might want to put the key bindings in a Binding Table that is specific to text editors.
Declare Handlers for the undo and redo commands, the code for undo might look like:
public class UndoHandler
{
#Inject
private Adapter _adapter;
#Execute
public void execute(#Named(IServiceConstants.ACTIVE_PART) final MPart part)
{
final ITextOperationTarget opTarget = _adapter.adapt(part.getObject(), ITextOperationTarget.class);
opTarget.doOperation(ITextOperationTarget.UNDO);
}
#CanExecute
public boolean canExecute(#Named(IServiceConstants.ACTIVE_PART) final MPart part)
{
final ITextOperationTarget opTarget = _adapter.adapt(part.getObject(), ITextOperationTarget.class);
if (opTarget == null)
return false;
return opTarget.canDoOperation(ITextOperationTarget.UNDO);
}
}
Redo would be similar but using ITextOperationTarget.REDO.
The order of doing/registering things is important. Be sure to connect the undo manager AFTER setting the document to the SourceViewer instance because on connect() the document will be retrieved from the viewer by the undo manager and if it doesn't find a document it will not register anything and undoable() will always return false.

Create view only for specific editor in eclipse

How can I show view when specific editor is selected and hide it when another is selected? I was looking for this in extension points but I found nothing :(
Is there any way to do this?
You need to register IPartListener with IPartService and then do appropriate things in partActivated, partBroughtToTop, etc. methods.
Make sure that the part is the editor you want:
public void partActivated(IWorkbenchPart part) {
if (part instanceof MySuperEditor) {
part.getSite().getPage().showView(MySuperView.ID);
}
}
and so on.
Let me know if that helps.

Wicket ListView not refreshing

I am taking my first steps with Apache Wicket and ran into the following problem. I have a ListView that displays a "delete" link right next to its entries. When the delete link is clicked, the entity represented by the list item is deleted from the database but the list itself does not get updated until I reload the page manually in the browser.
IModel<List<SampleEntity>> sampleEntityListModel = new LoadableDetachableModel<List<SampleEntity>>() {
#Override
protected List<SampleEntity> load() {
return mSampleEntityBA.findAll();
}
};
mListview = new ListView<SampleEntity>("listview", sampleEntityListModel) {
#Override
protected void populateItem(final ListItem<SampleEntity> item) {
item.add(new Label("listlabel", new PropertyModel<String>(item.getModelObject(),
"text")));
item.add(new Link<SampleEntity>("deleteLink", item.getModel()) {
#Override
public void onClick() {
mSampleEntityBA.delete(item.getModelObject());
}
});
}
};
When onClick called, item.getModelObject() pulls from the sampleEntityListModel which in turn calls mSampleEntityBA.findAll(). The model object of sampleEntityListModel will be cached for the duration on the request cycle (until it is detached - which is usually what you want) and is not aware of the call to delete().
In order to refresh the sampleEntityListModel, add a sampleEntityListModel.detach() call just after the delete (sampleEntityListModel must be made final, but this will not cause any extra state to be serialized). This will cause the model to fetch a fresh set of data when the list view is rendered later in the request cycle.
You probably want an AjaxLink instead of that Link, and then you have to make the list refresh, using the tactics described here, possibly adjusting a bit for the fact that the wiki has Wicket 1.3 code instead of 1.4.
But you might also be better off with a different repeater, such as a RefreshingView or a DataView. There are some examples of assorted repeaters here. While none of them are exactly what you're looking for, looking at that code might help.
looks like the problem is that your mSampleEntityBA.findAll(); is returning incorrect data. hard to help without seeing more code.
on a different note, you should really be using DataView when working with database-backed lists.
You might also want to check out JQGrid from the wiQuery project instead of DataView.

Hide certain actions from Swing's undo manager

I am trying to write a JTextPane which supports some sort of coloring: as the user is typing the text, I am running some code that colors the text according to a certain algorithm. This works well.
The problem is that the coloring operations is registered with the undo manager (a DefaultDocumentEvent with EventType.CHANGE). So when the user clicks undo the coloring disappears. Only at the second undo request the text itself is rolled back.
(Note that the coloring algorithm is somewhat slow so I cannot color the text as it is being inserted).
If I try to prevent the CHANGE events from reaching the undo manager I get an exception after several undo requests: this is because the document contents are not conforming to what the undoable-edit object expects.
Any ideas?
You could intercept the CHANGE edits and wrap each one in another UndoableEdit whose isSignificant() method returns false, before adding it to the UndoManager. Then each Undo command will undo the most recent INSERT or REMOVE edit, plus every CHANGE edit that occurred since then.
Ultimately, I think you'll find that the styling mechanism provided by JTextPane/StyledDocument/etc. is too limited for this kind of thing. It's slow, it uses too much memory, and it's based on the same Element tree that's used to keep track of the lexical structure of the document. It's okay (I guess) for applications in which the styles are applied by the user, like word processors, but not for a syntax highlighter that has to update the styles constantly as the user types.
There are several examples out there of syntax-highlighting editors based on custom implementations of the Swing JTextComponent, View and Document classes. Some, like JEdit, re-implement practically the whole javax.swing.text package, but I don't think you need to go that far.
How are you trying to prevent the CHANGE events from reaching the undo manager?
Can you not send the UndoManager a lastEdit().die() call immediately after the CHANGE is queued?
I can only assume how you are doing the text colouring. If you are doing it in the StyledDocuments change character attribute method you can get the undo listener and temporarily deregister it from the document for that operation and then once the colour change has finshed then you can reregister the listener.
Should be fine for what you are trying to do there.
hope that helps
I have just been through this problem. Here is my solution:
private class UndoManagerFix extends UndoManager {
private static final long serialVersionUID = 5335352180435980549L;
#Override
public synchronized void undo() throws CannotUndoException {
do {
UndoableEdit edit = editToBeUndone();
if (edit instanceof AbstractDocument.DefaultDocumentEvent) {
AbstractDocument.DefaultDocumentEvent event = (AbstractDocument.DefaultDocumentEvent) edit;
if (event.getType() == EventType.CHANGE) {
super.undo();
continue;
}
}
break;
} while (true);
super.undo();
}
#Override
public synchronized void redo() throws CannotRedoException {
super.redo();
int caretPosition = getCaretPosition();
do {
UndoableEdit edit = editToBeRedone();
if (edit instanceof AbstractDocument.DefaultDocumentEvent) {
AbstractDocument.DefaultDocumentEvent event = (AbstractDocument.DefaultDocumentEvent) edit;
if (event.getType() == EventType.CHANGE) {
super.redo();
continue;
}
}
break;
} while (true);
setCaretPosition(caretPosition);
}
}
It is an inner class in my custom JTextPane, so I can fix the caret position on redo.

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