[weld-dev] A ConversationManager API

[William Draï]

Right for the ConversationManager.beginConversation, there is already
Conversation.begin. I've been mistaken by the
ConversationManager.endConversation of Niklas' proposal.

I can maybe explain how we use the currently existing API, and in fact we
are relatively happy with what exists today, except for one thing :

start() {
    ConversatonManager manager = { get from BeanManager };
    manager.beginOrRestoreConversation(cid);
    Conversation conversation = { get from BeanManager };

    // Beginning of the ugly part !!
    String cid = ((ConversationImpl)conversation).getUnderlyingId();
    ConversationContext ctx =
Container.instance().deploymentServices().get(ContextLifecycle.class).getConversationContext();
    ctx.setBeanStore(new ConversationBeanStore(httpSession, cid));
    ctx.setActive(true);
    // End of the ugly part

    if (cid != null && conversation.isTransient())  // Don't remember why I
need this, beginOrRestore should be enough
        conversation.begin(cid);
}

end() {
    ConversationManager manager = { get from BeanManager };
    manager.cleanupConversation();
}

The main thing is that I would prefer not having to mess with bean stores
and contexts, so the manager.activateContext() looks fine. Ideally here what
I would like to do (I know, I'm too lazy :-)) :

start() {
    ConversatonManager manager = { get from BeanManager };
    manager.startupConversation();

    if (cid != null && conversation.isTransient())
        conversation.beginOrRestoreConversation(cid);
}

end() {
    ConversationManager manager = { get from BeanManager };
    manager.cleanupConversation();
}

>From Flex, there is no need to switch the conversation in a particular
request, but getting the list of the currently existing conversations with
ConversationManager.getCurrentConversationIds() can be useful.

Finally I really think it's necessary to be able to share a conversation
instance between different UIs and use the same ConversationContext
implementation for all. We could obviously ship a FlexConversationContext
with GraniteDS/CDI but we want to make possible to build applications where
a part of the UI uses JSF, another part uses Flex and why not another uses
ZK or the iPhone SDK.

William



Let's try it the other way around. I toss you the minimal JSF-centric API
> and the *framework reps of ZK, GraniteDS, SE and Remoting can speak up on
> what they need more control of along with their usecase* then Pete can
> comment and I just act as a secretary ;-) That way we don't end up with too
> many "nice to haves" in the API that could be worked around more or less
> easy.
>
> public interface ConversationManager
>
> {
>   /**
>    * Checks the state of the conversation context
>    *
>    * @return true if the conversation context is active, false otherwise
>    */
>   public abstract boolean isContextActive();
> // usecase: the conversation checks for active context before running
> methods
>
>
>   /**
>    * Activates the conversation context
>    *
>    * @return The conversation manager
>    *
>    * @throws IllegalStateException if the context is already active
>    */
>   public abstract ConversationManager activateContext();
> // usecase: any non-JSF framework will want to run this themselves
>
>
>   /**
>    * Deactivates the conversation context
>    *
>    * @return The conversation manager
>    *
>    * @throws IllegalStateException if the context is already deactive
>    */
>   public abstract ConversationManager deactivateContext();
> // usecase: any non-JSF framework will want to run this themselves
>
>   /**
>    * Resumes a long running conversation. If the cid is null, nothing is
> done and the current
>    * transient conversation is resumed
>    *
>    *
>    * @param cid The conversation id to restore
>    * @return The conversation manager
>    * @throws NonexistentConversationException If the non-transient
> conversation is not known
>    * @throws BusyConversationException If the conversation is locked and
> not released while waiting
>     * @throws IllegalStateException if the conversation context is not
> active
>    */
>   public abstract ConversationManager beginOrRestoreConversation(String
> cid);
> // usecase: start of the conversation lifecycle.
>
>   /**
>    * Destroys the current conversation if it's transient. Stores it for
> conversation
>    * propagation if it's non-transient
>    *
>    * @return
>
>    * @throws IllegalStateException if the conversation context is not
> active
>    */
>   public abstract ConversationManager cleanupConversation();
> // usecase: end of the conversation lifecycle.
>
>   /**
>    * Gets the current non-transient conversations
>    *
>    * @return The conversations mapped by id
>
>    * @throws IllegalStateException if the conversation context is not
> active
>    */
>   public abstract Map<String, Conversation> getConversations();
> // usecase: Conversation checks if begin(String) was called with a known
> cid (no need for a isCidInUse, actually)
>
>   /**
>    * Returns a new, session-unique conversation ID
>    *
>    * @return The conversation id
>
>    * @throws IllegalStateException if the conversation context is not
> active
>    */
>    public abstract String generateConversationId();
> // usecase: Conversation gets a cid for begin()
>
> Notice that the begin and end of lifecycle are big chunks. Speak up where
> you need more granularity. Also speak up if you want fancy switching stuff
> etc ;-) *Re-submit any wishes/suggestions you've done in the past* in this
> thread (method signature + usecase) so we can keep stuff together.
>
> ---
> Nik
>
>
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