Allow changing of camera controller

src/main/java/com/replaymod/replay/camera/CameraControllerRegistry.java

@@ -0,0 +1,26 @@
+package com.replaymod.replay.camera;
+
+import com.google.common.base.Function;
+import com.google.common.base.Preconditions;
+
+import java.util.Collections;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class CameraControllerRegistry {
+    private final Map<String, Function<CameraEntity, CameraController>> constructors = new ConcurrentHashMap<>();
+
+    public void register(String name, Function<CameraEntity, CameraController> constructor) {
+        Preconditions.checkState(!constructors.containsKey(name), "Controller " + name + " is already registered.");
+        constructors.put(name, constructor);
+    }
+
+    public Set<String> getControllers() {
+        return Collections.unmodifiableSet(constructors.keySet());
+    }
+
+    public CameraController create(String name, CameraEntity cameraEntity) {
+        return constructors.get(name).apply(cameraEntity);
+    }
+}