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https://issues.apache.org/jira/browse/TAP5-2383?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14121089#comment-14121089
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Geoff Callender commented on TAP5-2383:
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In an AJAX request, I think the server-side would have no way of knowing how
many subscribers there are within the page unless it exactly rebuilds the
entire page state. For example some subscribers could be within a loop, and
they might be conditional.
However, the client-side has the full page state, so I think that's where the
pub-sub has to happen.
How about a mechanism along these lines:
- give the Zone component a "refreshOnMessage" parameter, specifying a message
string; and
- give AjaxResponseRenderer a publishMessage(String s) method; and
- Tapestry could do the rest, client-side: it receives the message string,
identifies all the zone instances that asked to be refreshed when that string
appears, and triggers a refresh of each one.
What do you think?
> Serverside publish / subscribe mechanism
> ----------------------------------------
>
> Key: TAP5-2383
> URL: https://issues.apache.org/jira/browse/TAP5-2383
> Project: Tapestry 5
> Issue Type: New Feature
> Components: tapestry-core
> Reporter: Lance
> Priority: Minor
>
> In some cases, an event in one component should cause an action (eg ajax
> update) in another. When these components are siblings it sometimes gets
> tricky having to pass zone id's around and having one component update the
> other.
> It would be nice to decouple the components with a serverside pub/sub
> mechanism. Here's an initial brain dump on how it could work.
> {code:java}
> public class EditPersonComponent {
> @Parameter
> private Person person;
> @Inject
> private PersonDao personDao;
> @Inject
> private ComponentResources componentResources;
> void onSuccessFromPersonForm() {
> personDao.save(person);
> componentResources.publish("personUpdated", person); // new method on
> ComponentResources
> }
> }
> {code}
> {code:java}
> public class SomeOtherComponent {
> @Inject
> private AjaxResponseRenderer ajaxResponseRenderer;
> @Property
> private Person person;
> @Inject
> private Zone personZone;
> // new subscribe annotation (and naming convention?)
> @Subscribe("personUpdated")
> void onPersonUpdatedPublished(Person person) {
> this.person = person;
> ajaxResponseRenderer.addRender(personZone);
> }
> }
> {code}
> If this change was made on ComponentResources, we should probably add the
> following to support invoking publish events on the client
> {code}
> Link ComponentResources.createPublishLink(String eventType, Object... context)
> {code}
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