import java.util.Arrays;
/**
- * A trait indicating an object may generate events
+ * A trait indicating an object may generate events.
+ *
+ * Events are processed by passing an [`EventHandler`] to [`process_pending_events`].
+ *
+ * # Requirements
+ *
+ * See [`process_pending_events`] for requirements around event processing.
+ *
+ * When using this trait, [`process_pending_events`] will call [`handle_event`] for each pending
+ * event since the last invocation. The handler must either act upon the event immediately
+ * or preserve it for later handling.
+ *
+ * Note, handlers may call back into the provider and thus deadlocking must be avoided. Be sure to
+ * consult the provider's documentation on the implication of processing events and how a handler
+ * may safely use the provider (e.g., see [`ChannelManager::process_pending_events`] and
+ * [`ChainMonitor::process_pending_events`]).
+ *
+ * (C-not implementable) As there is likely no reason for a user to implement this trait on their
+ * own type(s).
+ *
+ * [`process_pending_events`]: Self::process_pending_events
+ * [`handle_event`]: EventHandler::handle_event
+ * [`ChannelManager::process_pending_events`]: crate::ln::channelmanager::ChannelManager#method.process_pending_events
+ * [`ChainMonitor::process_pending_events`]: crate::chain::chainmonitor::ChainMonitor#method.process_pending_events
*/
@SuppressWarnings("unchecked") // We correctly assign various generic arrays
public class EventsProvider extends CommonBase {
public static interface EventsProviderInterface {
/**
- * Gets the list of pending events which were generated by previous actions, clearing the list
- * in the process.
+ * Processes any events generated since the last call using the given event handler.
+ *
+ * Subsequent calls must only process new events. However, handlers must be capable of handling
+ * duplicate events across process restarts. This may occur if the provider was recovered from
+ * an old state (i.e., it hadn't been successfully persisted after processing pending events).
*/
- Event[] get_and_clear_pending_events();
+ void process_pending_events(EventHandler handler);
}
private static class LDKEventsProviderHolder { EventsProvider held; }
public static EventsProvider new_impl(EventsProviderInterface arg) {
final LDKEventsProviderHolder impl_holder = new LDKEventsProviderHolder();
impl_holder.held = new EventsProvider(new bindings.LDKEventsProvider() {
- @Override public long[] get_and_clear_pending_events() {
- Event[] ret = arg.get_and_clear_pending_events();
- long[] result = Arrays.stream(ret).mapToLong(ret_conv_7 -> ret_conv_7.ptr).toArray();
- /* TODO 2 Event */;
- return result;
+ @Override public void process_pending_events(long handler) {
+ EventHandler ret_hu_conv = new EventHandler(null, handler);
+ ret_hu_conv.ptrs_to.add(this);
+ arg.process_pending_events(ret_hu_conv);
}
});
return impl_holder.held;
}
/**
- * Gets the list of pending events which were generated by previous actions, clearing the list
- * in the process.
+ * Processes any events generated since the last call using the given event handler.
+ *
+ * Subsequent calls must only process new events. However, handlers must be capable of handling
+ * duplicate events across process restarts. This may occur if the provider was recovered from
+ * an old state (i.e., it hadn't been successfully persisted after processing pending events).
*/
- public Event[] get_and_clear_pending_events() {
- long[] ret = bindings.EventsProvider_get_and_clear_pending_events(this.ptr);
- Event[] ret_conv_7_arr = new Event[ret.length];
- for (int h = 0; h < ret.length; h++) {
- long ret_conv_7 = ret[h];
- Event ret_conv_7_hu_conv = Event.constr_from_ptr(ret_conv_7);
- ret_conv_7_hu_conv.ptrs_to.add(this);
- ret_conv_7_arr[h] = ret_conv_7_hu_conv;
- }
- return ret_conv_7_arr;
+ public void process_pending_events(EventHandler handler) {
+ bindings.EventsProvider_process_pending_events(this.ptr, handler == null ? 0 : handler.ptr);
+ this.ptrs_to.add(handler);
}
}