Bug 127655 [api] Must have a way to query quick assist context from source viewer
I20060214-0010 [api] Must have a way to query quick assist context from text viewer. In addition, quick assistant install must specify that besides ITextViewer also ITextViewerExtension7 must be present in order to get the invocation context. ==> assertion failure if this is not met.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/correction/JavaCorrectionAssistant.java
* next quick fix on same line by moving from left
	 * to right and restarting at end of line if the
	 * beginning of the line is reached.
	 *
	 * @see IQuickAssistAssistant#showPossibleQuickAssists()
	 */
	public String showPossibleQuickAssists() {
		fPosition= null;
		fCurrentAnnotations= null;
		
		if (fViewer == null || fViewer.getDocument() == null)
			
			return super.showPossibleQuickAssists();
		ArrayList resultingAnnotations= new ArrayList(20);
		try {
			Point selectedRange= fViewer.getSelectedRange();
			int currOffset= selectedRange.x;
			int currLength= selectedRange.y;
			boolean goToClosest= (currLength == 0);
			
			int newOffset= collectQuickFixableAnnotations(fEditor, currOffset, goToClosest, resultingAnnotations);
			if (newOffset != currOffset) {
				storePosition(currOffset, currLength);
				fViewer.setSelectedRange(newOffset, 0);
				fViewer.revealRange(newOffset, 0);
			}
		} catch (BadLocationException e) {
			JavaPlugin.log(e);
		}
		fCurrentAnnotations= (Annotation[]) resultingAnnotations.toArray(new Annotation[resultingAnnotations.size()]);