Collaboration Edit

Overview

Spreadsheet can support Collaboration Edit automatically as long as two or more Spreadsheet components share a common book model with proper scope. To enable this feature on a book object, we should call Book.setShareScope() before setting the book object to a Spreadsheet. Then, we should give the same book object to every Spreadsheet that joins the collaboration edit. After this, one user’s edit will automatically reflect to other users’ Spreadsheet and each user can also see others’ current selection box which are painted with different colors.

Limitation

This feature requires to share one Book object among multiple Spreadsheet components, so it doesn’t work in a clustering environment (cross among different Java VM).

Example

Here we demonstrate an example application that loads a book and shares it in “application” scope. A user can click a book name in the list to open it in the Spreadsheet. If two users open the same book and they are both actually editing on the same book model instance. One user’s edit will immediately reflect on another user’s Spreadsheet.

The screenshot below is what the user, Paul, sees and he can also see another user’s (John) current selection (purple box).

Another user, John, can also see Paul’s current selection (blue box) in his spreadsheet.

The controller’s code of above example:

public class CoeditComposer extends SelectorComposer<Component> {

    private static final long serialVersionUID = 1L;
    
    @Wire
    private Spreadsheet ss;
    @Wire
    private Listbox availableBookList;
    
    static private final Map<String,Book> sharedBook = 
        new HashMap<String,Book>();

    //omit initialization codes...

    @Listen("onSelect = #availableBookList")
    public void onBookSelect(){
        String bookName = availableBookList.getSelectedItem().getValue();
        Book book = loadBookFromAvailable(bookName);
        ss.setBook(book);
    }
    
    private Book loadBookFromAvailable(String bookname){
        Book book;
        synchronized (sharedBook){
            book = sharedBook.get(bookname);
            if(book==null){
                book = importBook(bookname);
                book.setShareScope("application");
                sharedBook.put(bookname, book);
            }
        }
        return book;
    }
    
    @Listen("onClick=#setUserName")
    public void setUserName(){
        ss.setUserName(userName.getValue());
    }
    
    
    private Book importBook(String bookname){
        if(!availableBookModel.contains(bookname)){
            return null;
        }
        Importer imp = Importers.getImporter();
        try {
            Book book = imp.imports(
                    WebApps.getCurrent().getResource("/WEB-INF/books/" + bookname),
                    bookname);
            return book;
        } catch (IOException e) {
            throw new RuntimeException(e.getMessage(),e);
        }
    }
}

• Line 10: For simplicity, we use a static map to simulate a shared book model repository.
• Line 24: When a user selects a book, we always return a shared Book object first if it exists.
• Line 27: You should call setShareScope() before setting the book object to a Spreadsheet.
• Line 36: You can give Spreadsheet user a more identifiable name by setUserName(). The name will appear on the selection box showing in other users’ Spreadsheet.