feat: added EventBus.removeAllEventHandlers, #1160

Author: AlmasB

fxgl-core/src/main/kotlin/com/almasb/fxgl/event/EventBus.kt

@@ -24,6 +24,8 @@ class EventBus {
 
     private val eventHandlers = Group()
 
+    private val subscribers = arrayListOf<Subscriber>()
+
     var isLoggingEnabled = true
 
     /**
@@ -33,7 +35,7 @@ class EventBus {
         eventHandlers.addEventHandler(eventType, eventHandler)
 
         @Suppress("UNCHECKED_CAST")
-        return Subscriber(this, eventType, eventHandler as EventHandler<in Event>)
+        return Subscriber(this, eventType, eventHandler as EventHandler<in Event>).also { subscribers.add(it) }
     }
 
     /**
@@ -43,6 +45,13 @@ class EventBus {
         eventHandlers.removeEventHandler(eventType, eventHandler)
     }
 
+    fun removeAllEventHandlers() {
+        // some of these may have already been unsubscribed, either via [removeEventHandler] or [unsubscribe],
+        // but given the following is a no-op when not subscribed, there is no need to update the list
+        subscribers.forEach { it.unsubscribe() }
+        subscribers.clear()
+    }
+
     /**
      * Fire given [event].
      * All listening parties will be notified.

fxgl-core/src/test/kotlin/com/almasb/fxgl/event/EventBusTest.kt

@@ -65,6 +65,17 @@ class EventBusTest {
 
                     eventBus.fireEvent(Event(EventType.ROOT))
 
+                    assertThat(count, `is`(2))
+                },
+
+                Executable {
+                    // add again and remove, but this time using removeAll
+                    eventBus.addEventHandler(EventType.ROOT, handler)
+
+                    eventBus.removeAllEventHandlers()
+
+                    eventBus.fireEvent(Event(EventType.ROOT))
+
                     assertThat(count, `is`(2))
                 }
         )