Bug 30291 SearchUsagesInFileAction should show dialog in case of failures
Build I20030122 SearchUsagesInFileAction should show a dialog in failure/error cases (e.g. code resolve fails).
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/search/SearchUsagesInFileAction.java
marker.setAttributes(attributes);
		return marker;
	}
	protected final IJavaElement getInput() {
		IClassFile classFile= getClassFile();
		if (classFile != null)
			return classFile;
		return getCompilationUnit();
	}
	
	protected ICompilationUnit getCompilationUnit() {
		return JavaPlugin.getDefault().getWorkingCopyManager().getWorkingCopy(fEditor.getEditorInput());
	}
	
	protected final IClassFile getClassFile() {
		IEditorInput input= fEditor.getEditorInput();
		if (input instanceof IClassFileEditorInput)
			return ((IClassFileEditorInput)input).getClassFile();
		return null;
	}
	
	protected final IDocument getDocument() {
		return fEditor.getDocumentProvider().getDocument(fEditor.getEditorInput());
	}
	
	protected final ITextSelection getTextSelection() {
		return (ITextSelection)fEditor.getSelectionProvider().getSelection();
	}
}