Injection de Dépendances

Lors de la création de votre classe de plugin, Sponge utilise une technique appelée « Injection de Dépendances » pour fournir des objets API à la classe principale de votre plugin. Certains de ces objets, tels que les « Loggers » et les chargeurs de configuration, sont spécifiques à votre plugin et réduisent le code que vous devez écrire pour effectuer certaines de ces tâches.

Avertissement

Sponge ne fait de l’injection que sur la classe principale de votre plugin. L’utilisation de @Inject sur d’autres classes ne fonctionnera pas à moins que vous n’injectiez un Injector dans votre classe principale, puis utilisiez cela pour créer d’autres classes.

Injections Simples

Les champs ou les paramètres de constructeur des types suivants peuvent être annotés avec @com.google.inject.Inject pour demander à Sponge de fournir des objets simples.

Les objets suivants sont les mêmes, quel que soit le plugin qui demande l’injection :

Les types suivants renvoient une instance appropriée pour le plugin :

PluginContainer - renvoie le conteneur de plugin associé au plugin dans lequel il est injecté
org.apache.logging.log4j.Logger - returns the logger associated with the plugin it is being injected into

Example: Injecting the Plugin Specific Logger and PluginContainer

We can signal to Sponge that you want to inject the logger in one of two ways, field or constructor injection. All simple injections work the same way in Sponge.

For field injection, you must annotate non-final fields with the @Inject annotation, as in the example below:

import com.google.inject.Inject;
import org.apache.logging.log4j.Logger;

@Inject
private Logger logger;

@Inject
private PluginContainer pluginContainer;

For constructor injection, you must create a constructor, annotate it with @Inject, and add the objects you want injecting as parameters, as in the example below:

import com.google.inject.Inject;
import org.apache.logging.log4j.Logger;

// For the purpose of this example, "Banana" is the class name

private final Logger logger;
private final PluginContainer pluginContainer;

@Inject
public Banana(Logger logger, PluginContainer pluginContainer) {
    this.logger = logger;
    this.pluginContainer = pluginContainer;
}

In both of these examples, the logger field will contain a Sponge provided logger and the pluginContainer field will contain the plugin’s PluginContainer after the object is constructed.

Configurate Injections

Astuce

View Configuration des plugins for a guide to configuration, specifically using the @DefaultConfig annotation.

Sponge is also able to inject Configurate specific objects into your plugin class, set up with suggested locations for your plugin configuration. These injections require an additional annotation on your injected type, which will be either ConfigDir or DefaultConfig, dependent on your use case.

The `DefaultConfig` Annotation

The DefaultConfig annotation is used to resolve a file location. DefaultConfig has a parameter sharedRoot, which alters the file that it points to (where <pluginid> is your plugin’s ID):

If sharedRoot is false, the annotation will point to the file config/<pluginid>/<pluginid>.conf.
If sharedRoot is true, the annotation will point to the file config/<pluginid>.conf.

The DefaultConfig annotation can be applied on the following types:

ConfigurationLoader<CommentedConfigurationNode> - provides a configuration loader that will load and save a HOCON file from the resolved file location
ConfigurationReference<CommentedConfigurationNode> - provides a ConfigurationReference that will load and save a HOCON file from the resolved file location
Path - stores the path to the file location, useful if you wish to use a different file format for your configuration (such as YAML).

Example Injection

The following example injects the HOCON configuration loader and the path it is pointing to via field injection.

import com.google.inject.Inject;
import org.spongepowered.api.config.DefaultConfig
import org.spongepowered.configurate.CommentedConfigurationNode;
import org.spongepowered.configurate.loader.ConfigurationLoader;

@Inject
@DefaultConfig(sharedRoot = false)
private ConfigurationLoader<CommentedConfigurationNode> loader;

@Inject
@DefaultConfig(sharedRoot = false)
private Path configFilePath;

Most users will only require the provided loader, which can then be interacted with in the normal way.

The `ConfigDir` annotation

The ConfigDir annotation is used to resolve a folder. The sharedRoot parameter works as follows (where <pluginid> is your plugin’s ID):

If sharedRoot is false, the annotation will point to the file config/<pluginid>/.
If sharedRoot is true, the annotation will point to the file config/.

The ConfigDir annotation can only be applied on the Path type to retrive this directory. It is generally most useful for plugins that require multiple configuration files, providing the directory to place them rather than a single file.

Full List of injectables

Type	Description
PluginContainer	Your plugin’s container
Logger	Your plugin’s log4j logger
System.Logger	Your plugin’s Java Logger
Path	Your plugin’s config location, use the `@DefaultConfig` or the `@ConfigDir` to give more detials
TypeSerializerCollection	Your plugin’s specific TypeSerializer’s
ConfigurationLoader	Your plugin’s config loader, use the `@DefaultConfig` to give more detail
ConfigurationReference	Your plugin’s config reference, use the `@DefaultConfig` to give more detial
Game	The Sponge global game instance
MinecraftVersion	The minecraft version the server is running
ChannelManager	The server’s channel manager
PluginManager	the server’s plugin manager
ConfigManager	the server’s configuration file manager
MetricsConfigManager	the server’s metric configurations manager
ServiceProvider.GameScoped	The initial service provider for the server
FactoryProvider	Not something plugins typically use
BuilderProvider	Not something plugins typically use
Path	Shared configuration path, used when `@DefaultConfig` and `@ConfigDir` are not used