Develop Reference

Why do I get "Unidentified mapping from registry minecraft:block"?

I am learning how to write Minecraft mods (version 1.14.4) and was able to make an item. Now I am trying to make a block. I am following this tutorial video which actually covers 1.14.3, but I thought it would be close enough.
I am currently getting this error:
[20Mar2020 14:09:10.522] [Server thread/INFO] [net.minecraftforge.registries.ForgeRegistry/REGISTRIES]: Registry Block: Found a missing id from the world examplemod:examplemod
[20Mar2020 14:09:10.613] [Server thread/ERROR] [net.minecraftforge.registries.GameData/REGISTRIES]: Unidentified mapping from registry minecraft:block
examplemod:examplemod: 676
I also get presented with this at runtime:
I have tried messing around with how i'm naming the registries but I just can't seem to pin down what the issue is. Maybe i'm not formatting my json files correctly?
Note that ItemList and BlockList are just classes that contain static instances of each Block/Item I have created.
ExampleMod.java:
// The value here should match an entry in the META-INF/mods.toml file
#Mod(ExampleMod.MOD_ID)
public class ExampleMod
{
// Directly reference a log4j logger.
private static final Logger LOGGER = LogManager.getLogger();
public static final String MOD_ID = "examplemod";
public ExampleMod() {
// Register the setup method for modloading
FMLJavaModLoadingContext.get().getModEventBus().addListener(this::setup);
// Register the enqueueIMC method for modloading
FMLJavaModLoadingContext.get().getModEventBus().addListener(this::enqueueIMC);
// Register the processIMC method for modloading
FMLJavaModLoadingContext.get().getModEventBus().addListener(this::processIMC);
// Register the doClientStuff method for modloading
FMLJavaModLoadingContext.get().getModEventBus().addListener(this::doClientStuff);
// Register ourselves for server and other game events we are interested in
MinecraftForge.EVENT_BUS.register(this);
}
private void setup(final FMLCommonSetupEvent event)
{
// some preinit code
LOGGER.info("HELLO FROM PREINIT");
LOGGER.info("DIRT BLOCK >> {}", Blocks.DIRT.getRegistryName());
}
private void doClientStuff(final FMLClientSetupEvent event) {
// do something that can only be done on the client
LOGGER.info("Got game settings {}", event.getMinecraftSupplier().get().gameSettings);
}
private void enqueueIMC(final InterModEnqueueEvent event)
{
// some example code to dispatch IMC to another mod
InterModComms.sendTo(ExampleMod.MOD_ID, "helloworld", () -> { LOGGER.info("Hello world from the MDK"); return "Hello world";});
}
private void processIMC(final InterModProcessEvent event)
{
// some example code to receive and process InterModComms from other mods
LOGGER.info("Got IMC {}", event.getIMCStream().
map(m->m.getMessageSupplier().get()).
collect(Collectors.toList()));
}
// You can use SubscribeEvent and let the Event Bus discover methods to call
#SubscribeEvent
public void onServerStarting(FMLServerStartingEvent event) {
// do something when the server starts
LOGGER.info("HELLO from server starting");
}
// You can use EventBusSubscriber to automatically subscribe events on the contained class (this is subscribing to the MOD
// Event bus for receiving Registry Events)
#Mod.EventBusSubscriber(bus=Mod.EventBusSubscriber.Bus.MOD)
public static class RegistryEvents {
#SubscribeEvent
public static void onItemsRegistry(final RegistryEvent.Register<Item> blockItemEvent)
{
ItemList.bomb_item = new Item(new Item.Properties().group(ItemGroup.COMBAT));
ItemList.bomb_item.setRegistryName(new ResourceLocation(ExampleMod.MOD_ID, "bomb_item"));
ItemList.mystery_block = new BlockItem(BlockList.mystery_block, new Item.Properties().group(ItemGroup.MISC));
ItemList.mystery_block.setRegistryName(new ResourceLocation(ExampleMod.MOD_ID, "mystery_block"));
blockItemEvent.getRegistry().registerAll(ItemList.bomb_item, ItemList.mystery_block);
LOGGER.info("Items registered.");
}
#SubscribeEvent
public static void onBlocksRegistry(final RegistryEvent.Register<Block> blockRegistryEvent) {
BlockList.mystery_block = new Block(Block.Properties.create(Material.CAKE)
.hardnessAndResistance(2.0f, 2.0f)
.sound(SoundType.GLASS));
BlockList.mystery_block.setRegistryName(new ResourceLocation(MOD_ID, "mystery_block"));
blockRegistryEvent.getRegistry().registerAll(BlockList.mystery_block);
LOGGER.info("Blocks registered.");
}
}
}
blockstates/mystery_block.json:
{
"variants": {
"": {
"model": "examplemod:block/mystery_block"
}
}
}
models/block/mystery_block.json:
{
"parent": "block/cube_all",
"textures": {
"all": "examplemod:block/mystery_block"
}
}
models/item/mystery_block.json:
{
"parent": "examplemod:block/mystery_block"
}

All that means is that at some point you had a block registered as "examplemod:examplemod", and now you don't. You can safely ignore the message. If you start a new world instead of opening an old one, you won't get that message.
As an aside, HarryTalks is not a recommended way to learn to mod (on the Minecraft Forge forums ). Apparently he uses several bad practices (I have not actually used them).
Alternative suggestions are Cadiboo's example mod, or McJty's tutorials.

Callback-driven Spring Cloud Dataflow source application

I want to create a Spring Cloud Dataflow source application based on a lib that connects to a messaging service (IRC, actually) and calls my callback when a message arrives. The only goal of the source app is to create an SCDF message from the received IRC message and send it to the stream.
I have come up with the following solution:
The IrcListener class annotated with #Component does some configuration and starts listening for IRC messages when the start() method is called. When a message is received its onGenericMessage callback simply sends the message to the stream via the injected source property:
#Component
public class IrcListener extends ListenerAdapter {
#Override
public void onGenericMessage(GenericMessageEvent event) {
Message msg = new Message();
msg.content = event.getMessage();
source.output().send(MessageBuilder.withPayload(msg).build());
}
private Source source;
private String _name;
private String _server;
private List<String> _channels;
public void start() throws Exception {
Configuration configuration = new Configuration.Builder()
.setName(_name)
.addServer(_server)
.addAutoJoinChannels(_channels)
.addListener(this)
.buildConfiguration();
PircBotX bot = new PircBotX(configuration);
bot.startBot();
}
#Autowired
public IrcListener(Source source) {
this.source = source;
_name = "ircsource";
_server = "irc.rizon.net";
_channels = Arrays.asList("#test".split(","));
}
}
The main class runs Spring Application and calls the aforementioned start() method on the IrcListener component.
#EnableBinding(Source.class)
#SpringBootApplication
public class IrcStreamApplication {
public static void main(String[] args) throws Exception {
ConfigurableApplicationContext context = SpringApplication.run(IrcStreamApplication.class, args);
context.getBean(IrcListener.class).start();
}
}
This works ok and the messages are received and published to the stream successfully, but I'd like to know whether this is the right approach to take in the Spring (Cloud Dataflow) universe and or maybe I am missing something important?

It looks ok; but, generally, message-driven sources extend MessageProducerSupport and call sendMessage(Message<?>).
(and override doStart() in this case).
It would give you access to message history tracking and error handling (if the send fails).

Updating Dropwizard config at runtime

Is it possible to have my app update the config settings at runtime? I can easily expose the settings I want in my UI but is there a way to allow the user to update settings and make them permanent ie save them to the config.yaml file? The only way I can see it to update the file by hand then restart the server which seems a bit limiting.

Yes. It is possible to reload the service classes at runtime.
Dropwizard by itself does not have the way to reload the app, but jersey has.
Jersey uses a container object internally to maintain the running application. Dropwizard uses the ServletContainer class of Jersey to run the application.
How to reload the app without restarting it -
Get a handle to the container used internally by jersey
You can do this by registering a AbstractContainerLifeCycleListener in Dropwizard Environment before starting the app. and implement its onStartup method as below -
In your main method where you start the app -
//getting the container instance
environment.jersey().register(new AbstractContainerLifecycleListener() {
#Override
public void onStartup(Container container) {
//initializing container - which will be used to reload the app
_container = container;
}
});
Add a method to your app to reload the app. It will take in the list of string which are the names of the service classes you want to reload. This method will call the reload method of the container with the new custom DropWizardConfiguration instance.
In your Application class
public static synchronized void reloadApp(List<String> reloadClasses) {
DropwizardResourceConfig dropwizardResourceConfig = new DropwizardResourceConfig();
for (String className : reloadClasses) {
try {
Class<?> serviceClass = Class.forName(className);
dropwizardResourceConfig.registerClasses(serviceClass);
System.out.printf(" + loaded class %s.\n", className);
} catch (ClassNotFoundException ex) {
System.out.printf(" ! class %s not found.\n", className);
}
}
_container.reload(dropwizardResourceConfig);
}
For more details see the example documentation of jersey - jersey example for reload
Consider going through the code and documentation of following files in Dropwizard/Jersey for a better understanding -
Container.java
ContainerLifeCycleListener.java
ServletContainer.java
AbstractContainerLifeCycleListener.java
DropWizardResourceConfig.java
ResourceConfig.java

No.
Yaml file is parsed at startup and given to the application as Configuration object once and for all. I believe you can change the file after that but it wouldn't affect your application until you restart it.
Possible follow up question: Can one restart the service programmatically?
AFAIK, no. I've researched and read the code somewhat for that but couldn't find a way to do that yet. If there is, I'd love to hear that :).

I made a task that reloads the main yaml file (it would be useful if something in the file changes). However, it is not reloading the environment. After researching this, Dropwizard uses a lot of final variables and it's quite hard to reload these on the go, without restarting the app.
class ReloadYAMLTask extends Task {
private String yamlFileName;
ReloadYAMLTask(String yamlFileName) {
super("reloadYaml");
this.yamlFileName = yamlFileName;
}
#Override
public void execute(ImmutableMultimap<String, String> parameters, PrintWriter output) throws Exception {
if (yamlFileName != null) {
ConfigurationFactoryFactory configurationFactoryFactory = new DefaultConfigurationFactoryFactory<ReportingServiceConfiguration>();
ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();
Validator validator = validatorFactory.getValidator();
ObjectMapper objectMapper = Jackson.newObjectMapper();
final ConfigurationFactory<ServiceConfiguration> configurationFactory = configurationFactoryFactory.create(ServiceConfiguration.class, validator, objectMapper, "dw");
File confFile = new File(yamlFileName);
configurationFactory.build(new File(confFile.toURI()));
}
}
}

You can change the configuration in the YAML and read it while your application is running. This will not however restart the server or change any server configurations. You will be able to read any changed custom configurations and use them. For example, you can change the logging level at runtime or reload other custom settings.
My solution -
Define a custom server command. You should use this command to start your application instead of the "server" command.
ArgsServerCommand.java
public class ArgsServerCommand<WC extends WebConfiguration> extends EnvironmentCommand<WC> {
private static final Logger LOGGER = LoggerFactory.getLogger(ArgsServerCommand.class);
private final Class<WC> configurationClass;
private Namespace _namespace;
public static String COMMAND_NAME = "args-server";
public ArgsServerCommand(Application<WC> application) {
super(application, "args-server", "Runs the Dropwizard application as an HTTP server specific to my settings");
this.configurationClass = application.getConfigurationClass();
}
/*
* Since we don't subclass ServerCommand, we need a concrete reference to the configuration
* class.
*/
#Override
protected Class<WC> getConfigurationClass() {
return configurationClass;
}
public Namespace getNamespace() {
return _namespace;
}
#Override
protected void run(Environment environment, Namespace namespace, WC configuration) throws Exception {
_namespace = namespace;
final Server server = configuration.getServerFactory().build(environment);
try {
server.addLifeCycleListener(new LifeCycleListener());
cleanupAsynchronously();
server.start();
} catch (Exception e) {
LOGGER.error("Unable to start server, shutting down", e);
server.stop();
cleanup();
throw e;
}
}
private class LifeCycleListener extends AbstractLifeCycle.AbstractLifeCycleListener {
#Override
public void lifeCycleStopped(LifeCycle event) {
cleanup();
}
}
}
Method to reload in your Application -
_ymlFilePath = null; //class variable
public static boolean reloadConfiguration() throws IOException, ConfigurationException {
boolean reloaded = false;
if (_ymlFilePath == null) {
List<Command> commands = _configurationBootstrap.getCommands();
for (Command command : commands) {
String commandName = command.getName();
if (commandName.equals(ArgsServerCommand.COMMAND_NAME)) {
Namespace namespace = ((ArgsServerCommand) command).getNamespace();
if (namespace != null) {
_ymlFilePath = namespace.getString("file");
}
}
}
}
ConfigurationFactoryFactory configurationFactoryFactory = _configurationBootstrap.getConfigurationFactoryFactory();
ValidatorFactory validatorFactory = _configurationBootstrap.getValidatorFactory();
Validator validator = validatorFactory.getValidator();
ObjectMapper objectMapper = _configurationBootstrap.getObjectMapper();
ConfigurationSourceProvider provider = _configurationBootstrap.getConfigurationSourceProvider();
final ConfigurationFactory<CustomWebConfiguration> configurationFactory = configurationFactoryFactory.create(CustomWebConfiguration.class, validator, objectMapper, "dw");
if (_ymlFilePath != null) {
// Refresh logging level.
CustomWebConfiguration webConfiguration = configurationFactory.build(provider, _ymlFilePath);
LoggingFactory loggingFactory = webConfiguration.getLoggingFactory();
loggingFactory.configure(_configurationBootstrap.getMetricRegistry(), _configurationBootstrap.getApplication().getName());
// Get my defined custom settings
CustomSettings customSettings = webConfiguration.getCustomSettings();
reloaded = true;
}
return reloaded;
}

Although this feature isn't supported out of the box by dropwizard, you're able to accomplish this fairly easy with the tools they give you.
Before I get started, note that this isn't a complete solution for the question asked as it doesn't persist the updated config values to the config.yml. However, this would be easy enough to implement yourself simply by writing to the config file from the application. If anyone would like to write this implementation feel free to open a PR on the example project I've linked below.
Code
Start off with a minimal config:
config.yml
myConfigValue: "hello"
And it's corresponding configuration file:
ExampleConfiguration.java
public class ExampleConfiguration extends Configuration {
private String myConfigValue;
public String getMyConfigValue() {
return myConfigValue;
}
public void setMyConfigValue(String value) {
myConfigValue = value;
}
}
Then create a task which updates the config:
UpdateConfigTask.java
public class UpdateConfigTask extends Task {
ExampleConfiguration config;
public UpdateConfigTask(ExampleConfiguration config) {
super("updateconfig");
this.config = config;
}
#Override
public void execute(Map<String, List<String>> parameters, PrintWriter output) {
config.setMyConfigValue("goodbye");
}
}
Also for demonstration purposes, create a resource which allows you to get the config value:
ConfigResource.java
#Path("/config")
public class ConfigResource {
private final ExampleConfiguration config;
public ConfigResource(ExampleConfiguration config) {
this.config = config;
}
#GET
public Response handleGet() {
return Response.ok().entity(config.getMyConfigValue()).build();
}
}
Finally wire everything up in your application:
ExampleApplication.java (exerpt)
environment.jersey().register(new ConfigResource(configuration));
environment.admin().addTask(new UpdateConfigTask(configuration));
Usage
Start up the application then run:
$ curl 'http://localhost:8080/config'
hello
$ curl -X POST 'http://localhost:8081/tasks/updateconfig'
$ curl 'http://localhost:8080/config'
goodbye
How it works
This works simply by passing the same reference to the constructor of ConfigResource.java and UpdateConfigTask.java. If you aren't familiar with the concept see here:
Is Java "pass-by-reference" or "pass-by-value"?
The linked classes above are to a project I've created which demonstrates this as a complete solution. Here's a link to the project:
scottg489/dropwizard-runtime-config-example
Footnote: I haven't verified this works with the built in configuration. However, the dropwizard Configuration class which you need to extend for your own configuration does have various "setters" for internal configuration, but it may not be safe to update those outside of run().
Disclaimer: The project I've linked here was created by me.

Android Restlet framework - Get list of the Files and download file

I have in my app Restlet server and If I open the server address in the browser then the server should return list of files in some folder and If the user click on the file then it should download the file.
I looked at this tutorial. Part 6 Serving static file. It´s this code:
public static final String ROOT_URI = "file:///c:/restlet/docs/api/";
[...]
// Create a component
Component component = new Component();
component.getServers().add(Protocol.HTTP, 8182);
component.getClients().add(Protocol.FILE);
// Create an application
Application application = new Application() {
#Override
public Restlet createInboundRoot() {
return new Directory(getContext(), ROOT_URI);
}
};
// Attach the application to the component and start it
component.getDefaultHost().attach(application);
component.start();
but if I use for example file:///sdcard/ in URI, then if I open the address in the browser I get
Not Found
The server has not found anything matching the request URI
You can get technical details here.
Please continue your visit at our home page.
What´s wrong? How can I return list of the files with Restlet?

My solution:
mWebServerComponent = new Component();
mWebServerComponent.getClients().add(Protocol.FILE);
mWebServerComponent.getServers().add(Protocol.HTTP, 8182);
mWebServerComponent.getDefaultHost().attach(new FileApplication());
try {
mWebServerComponent.start();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
And the FileApplication class:
public class FileApplication extends Application {
// for example: public static final String ROOT_URI =
// "file:///C:/restlet-jee-2.0.6/docs/api/";
#Override
public synchronized Restlet createInboundRoot() {
String ROOT_URI = "file:///"
+ Environment.getExternalStorageDirectory() + "/";
Directory directory = new Directory(getContext(),
LocalReference.localizePath(ROOT_URI));
directory.setListingAllowed(true);
Router router = new Router(getContext());
router.attach("/files", directory);
return router;
}
}

How to get an existing websocket instance

I'm working on an application that uses Websockets (Java EE 7) to send messages to all the connected clients asynchronously. The server (Websocket endpoint) should send these messages whenever a new article (an engagement modal in my app) is created.
Everytime a connection is established to the websocket endpoint, I'm adding the corresponding session to a list, which I could be able to access outside.
But the problem I had is, when I'm accessing this created websocket endpoint to which all the clients connected from outside (any other business class), I've get the existing instance (like a singleton).
So, can you please suggest me a way I can get an existing instance of the websocket endpoint, as I can't create it as new MyWebsocketEndPoint() coz it'll be created by the websocket internal mechanism whenever the request from a client is received.
For a ref:
private static WebSocketEndPoint INSTANCE = null;
public static WebSocketEndPoint getInstance() {
if(INSTANCE == null) {
// Instead of creating a new instance, I need an existing one
INSTANCE = new WebSocketEndPoint ();
}
return INSTANCE;
}
Thanks in advance.

The container creates a separate instance of the endpoint for every client connection, so you can't do what you're trying to do. But I think what you're trying to do is send a message to all the active client connections when an event occurs, which is fairly straightforward.
The javax.websocket.Session class has the getBasicRemote method to retrieve a RemoteEndpoint.Basic instance that represents the endpoint associated with that session.
You can retrieve all the open sessions by calling Session.getOpenSessions(), then iterate through them. The loop will send each client connection a message. Here's a simple example:
#ServerEndpoint("/myendpoint")
public class MyEndpoint {
#OnMessage
public void onMessage(Session session, String message) {
try {
for (Session s : session.getOpenSessions()) {
if (s.isOpen()) {
s.getBasicRemote().sendText(message);
}
} catch (IOException ex) { ... }
}
}
But in your case, you probably want to use CDI events to trigger the update to all the clients. In that case, you'd create a CDI event that a method in your Websocket endpoint class observes:
#ServerEndpoint("/myendpoint")
public class MyEndpoint {
// EJB that fires an event when a new article appears
#EJB
ArticleBean articleBean;
// a collection containing all the sessions
private static final Set<Session> sessions =
Collections.synchronizedSet(new HashSet<Session>());
#OnOpen
public void onOpen(final Session session) {
// add the new session to the set
sessions.add(session);
...
}
#OnClose
public void onClose(final Session session) {
// remove the session from the set
sessions.remove(session);
}
public void broadcastArticle(#Observes #NewArticleEvent ArticleEvent articleEvent) {
synchronized(sessions) {
for (Session s : sessions) {
if (s.isOpen()) {
try {
// send the article summary to all the connected clients
s.getBasicRemote().sendText("New article up:" + articleEvent.getArticle().getSummary());
} catch (IOException ex) { ... }
}
}
}
}
}
The EJB in the above example would do something like:
...
#Inject
Event<ArticleEvent> newArticleEvent;
public void publishArticle(Article article) {
...
newArticleEvent.fire(new ArticleEvent(article));
...
}
See the Java EE 7 Tutorial chapters on WebSockets and CDI Events.
Edit: Modified the #Observer method to use an event as a parameter.
Edit 2: wrapped the loop in broadcastArticle in synchronized, per #gcvt.
Edit 3: Updated links to Java EE 7 Tutorial. Nice job, Oracle. Sheesh.

Actually, WebSocket API provides a way how you can control endpoint instantiation. See https://tyrus.java.net/apidocs/1.2.1/javax/websocket/server/ServerEndpointConfig.Configurator.html
simple sample (taken from Tyrus - WebSocket RI test):
public static class MyServerConfigurator extends ServerEndpointConfig.Configurator {
public static final MyEndpointAnnotated testEndpoint1 = new MyEndpointAnnotated();
public static final MyEndpointProgrammatic testEndpoint2 = new MyEndpointProgrammatic();
#Override
public <T> T getEndpointInstance(Class<T> endpointClass) throws InstantiationException {
if (endpointClass.equals(MyEndpointAnnotated.class)) {
return (T) testEndpoint1;
} else if (endpointClass.equals(MyEndpointProgrammatic.class)) {
return (T) testEndpoint2;
}
throw new InstantiationException();
}
}
You need to register this to an endpoint:
#ServerEndpoint(value = "/echoAnnotated", configurator = MyServerConfigurator.class)
public static class MyEndpointAnnotated {
#OnMessage
public String onMessage(String message) {
assertEquals(MyServerConfigurator.testEndpoint1, this);
return message;
}
}
or you can use it with programmatic endpoints as well:
public static class MyApplication implements ServerApplicationConfig {
#Override
public Set<ServerEndpointConfig> getEndpointConfigs(Set<Class<? extends Endpoint>> endpointClasses) {
return new HashSet<ServerEndpointConfig>
(Arrays.asList(ServerEndpointConfig.Builder
.create(MyEndpointProgrammatic.class, "/echoProgrammatic")
.configurator(new MyServerConfigurator())
.build()));
}
#Override
public Set<Class<?>> getAnnotatedEndpointClasses(Set<Class<?>> scanned) {
return new HashSet<Class<?>>(Arrays.asList(MyEndpointAnnotated.class));
}
Of course it is up to you if you will have one configurator used for all endpoints (ugly ifs as in presented snippet) or if you'll create separate configurator for each endpoint.
Please do not copy presented code as it is - this is only part of Tyrus tests and it does violate some of the basic OOM paradigms.
See https://github.com/tyrus-project/tyrus/blob/1.2.1/tests/e2e/src/test/java/org/glassfish/tyrus/test/e2e/GetEndpointInstanceTest.java for complete test.