1 files changed, 37 insertions, 0 deletions
diff --git a/src/main/kotlin/moe/nea/firmament/events/FirmamentEventBus.kt b/src/main/kotlin/moe/nea/firmament/events/FirmamentEventBus.kt
new file mode 100644
index 0000000..842cdf1
--- /dev/null
+++ b/src/main/kotlin/moe/nea/firmament/events/FirmamentEventBus.kt
@@ -0,0 +1,37 @@
+package moe.nea.firmament.events
+
+import java.util.concurrent.CopyOnWriteArrayList
+import moe.nea.firmament.Firmament
+
+/**
+ * A pubsub event bus.
+ *
+ * [subscribe] to events [publish]ed on this event bus.
+ * Subscriptions may not necessarily be delivered in the order or registering.
+ */
+open class FirmamentEventBus<T : FirmamentEvent> {
+    data class Handler<T>(val invocation: (T) -> Unit, val receivesCancelled: Boolean)
+
+    private val toHandle: MutableList<Handler<T>> = CopyOnWriteArrayList()
+    fun subscribe(handle: (T) -> Unit) {
+        subscribe(handle, false)
+    }
+
+    fun subscribe(handle: (T) -> Unit, receivesCancelled: Boolean) {
+        toHandle.add(Handler(handle, receivesCancelled))
+    }
+
+    fun publish(event: T): T {
+        for (function in toHandle) {
+            if (function.receivesCancelled || event !is FirmamentEvent.Cancellable || !event.cancelled) {
+                try {
+                    function.invocation(event)
+                } catch (e: Exception) {
+                    Firmament.logger.error("Caught exception during processing event $event", e)
+                }
+            }
+        }
+        return event
+    }
+
+}