Router is hard to use

[Clashsoft]

1. registerRoutes can only be called once, but it's not possible to test whether it has been.

    @OnInit
    void loadRoutes() {
        try {
            router.registerRoutes(ingameRoutes);
        } catch (IllegalStateException ignored) {
        }
    }

2. The logic for error 3005 is only in renderRoute (which is meant for controllers), but not in getController (which is useful to instantiate components and initAndRender them later). Since routes.containsPath(route) cannot be called outside the Router class, one has to catch the (deeply nested) exception:

java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
	at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1863)
	at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1731)
	at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
	at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:232)
	at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:189)
	at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
	at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
	at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
	at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
	at javafx.event.Event.fireEvent(Event.java:198)
	at javafx.scene.Scene$ClickGenerator.postProcess(Scene.java:3689)
	at javafx.scene.Scene$MouseHandler.process(Scene.java:3994)
	at javafx.scene.Scene.processMouseEvent(Scene.java:1891)
	at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2709)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:411)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:301)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:400)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$2(GlassViewEventHandler.java:450)
	at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:430)
	at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:449)
	at com.sun.glass.ui.View.handleMouseEvent(View.java:551)
	at com.sun.glass.ui.View.notifyMouse(View.java:937)
	at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
	at com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:184)
	at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: java.lang.reflect.InvocationTargetException
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:115)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
Caused by: java.lang.reflect.InvocationTargetException

	at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:72)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:270)
	at com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:84)
	at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1858)
	... 37 more
Caused by: java.lang.NullPointerException: Cannot invoke "java.lang.reflect.Field.getName()" because "provider" is null
	at org.fulib.fx.util.ReflectionUtil.getInstanceOfProviderField(ReflectionUtil.java:106)
Caused by: java.lang.NullPointerException: Cannot invoke "java.lang.reflect.Field.getName()" because "provider" is null

	at org.fulib.fx.controller.Router.getController(Router.java:145)
	at io.github.sekassel.stp24.controller.IngameController.showOverlay(IngameController.java:539)
	at io.github.sekassel.stp24.controller.IngameController.showSystem(IngameController.java:469)
	at io.github.sekassel.stp24.controller.IngameController.lambda$setUserEmpire$3(IngameController.java:233)
	at io.github.sekassel.stp24.controller.ingame.SystemItemComponent.onClick(SystemItemComponent.java:86)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	... 44 more

3. getController is named incorrectly as it is useful for creating components as well.