3.1.0.alpha5

Support for Persistent Messages in Discussion Components

Messages added to a CollaborationMessageList can now be persisted on an external backend to retain them when the application restarts. You can set a CollaborationMessagePersister on the list and implement your logic to e.g. save messages to a database.

CollaborationMessagePersister persister = CollaborationMessagePersister.fromCallbacks(
    fetchQuery -> messageRepository
        .findAllByTopicSince(fetchQuery.getTopicId(), fetchQuery.getSince())
        .stream().map(entity -> new CollaborationMessage(
            new UserInfo(entity.getAuthor().getId()),
            entity.getText(),
            entity.getTime()
        )),
    persistRequest -> {
        CollaborationMessage message = persistRequest.getMessage();
        MessageEntity entity = new MessageEntity(
            message.getText(),
            persistRequest.getTopicId(),
            userRepository.findById(message.getUser().getId());
        );
        messageRepository.save(entity);
    });

CollaborationMessageList list = new CollaborationMessageList(user, topic, persister);

Submitter API for custom input components

CollaborationMessageInput is the provided component to submit messages to a CollaborationMessageList. Now you can connect a custom component to the list and configure it via a CollaborationMessageSubmitter which will be activated when the list connects to the topic.

CollaborationMessageList list = new CollaborationMessageList(user, topic); 
TextField field = new TextField();
Button button = new Button();
button.setEnabled(false);

list.setSubmitter(activationContext -> {
    button.setEnabled(true);
    Registration registration = button.addClickListener(event ->
            activationContext.appendMessage(field.getValue()));
    return () -> {
        registration.remove();
        button.setEnabled(false);
    };
});

add(list, field, button);

New CollaborationList

CollaborationList is a collaborative list of item you can obtain via TopicConnection::getNamedList. The list supports getting its items, appending new ones, and subscribing to list changes:

CollaborationEngine.getInstance().openTopicConnection(this, "topic", user, connection -> {
    CollaborationList list = connection.getNamedList("notifications");
    list.subscribe(event -> {
        event.getAddedItem(String.class).ifPresent(Notification::show);
    });
    return () -> {};
});

Other Changes

• Fixed field highlight inside Dialog.
• Providing images as stream resources with CollaborationMessageList::setImageProvider.
• CollaborationMessageInput now takes CollaborationMessageList as a constructor argument.

Compatibility

This version is targeted for Vaadin 20, and will be included in the following Vaadin 20 pre-release.