(8.3) ProjectResourceListener Replacement

Module Development
1

In 8.1, I'm using a ProjectResourceListener with a filter to listen for changes to my project resources.

How should I handle this in 8.3?

I see that I can register a ResourceCollectionListener with ProjectManager::addListener, but I don't understand the ResourceCollectionChangeEvent.

What is the contextObject?

2

First, depending on what you're doing, I'd highly recommend moving to a ResourceCollectionLifecycleFactory so we can do the boilerplate for you instead of you having to create listeners.

The Javadocs don't do a great job explaining WTF this is, but this is the common abstraction we use across all of our "create instances of something on the gateway when project resources change" pattern:

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All that aside,
The contextObject added to change events is just a generic escape hatch we use to smuggle some signals for internal usage across the generic configuration system. I would just ignore it (pass null).

Also, ResourceCollectionListener is "a whole project was added/removed/updated". You probably want a listener within that project, which is a ResourceListener.

3

Awesome, thanks so much, this makes way more sense :laughing:

Here's what I've come up with:

class ClientResourceChangeListener(
    val sessionMonitor: PerspectiveSessionMonitor,
    projectManager: ProjectManager,
) : ResourceCollectionLifecycleFactory<ResourceCollectionLifecycle>(projectManager) {

    val filter = ResourceFilter(ApplicationScope.ALL, listOf(ClientResource.type))
    
    override fun getResourceFilter(): ResourceFilter {
        return filter
    }

    override fun createLifecycle(
        collection: RuntimeResourceCollection
    ): ResourceCollectionLifecycle {
        return ClientResourceSessionNotifier(sessionMonitor, collection)
    }
}

class ClientResourceSessionNotifier(
    val sessionMonitor: PerspectiveSessionMonitor,
    val collection: RuntimeResourceCollection,
) : ResourceCollectionLifecycle(collection) {

    companion object {
        const val PROTOCOL = "periscope-client-resource-notifier"
    }

    fun notify() {
        sessionMonitor.getSessionsForProject(collection.name).forEach {
            it.pages.forEach { page -> page.send(PROTOCOL, JsonObject()) }
        }
    }

    override fun onStartup(resources: List<Resource>) {}

    override fun onShutdown(resourceIds: List<ResourceId>) {}

    override fun onResourcesCreated(resources: List<Resource>) = notify()

    override fun onResourcesModified(resources: List<Resource>) = notify()

    override fun onResourcesDeleted(resources: List<ResourceId>) = notify()
}