Dependency Injection
Sponge uses dependency injection to provide instances of the API to plugins. Dependency injection allows plugins to designate a few API types that will be injected after construction.
Temporary List of Injected Types
- ConfigDir (annotation on Path or File)
Used to inject the plugin’s configuration directory:
./config/
OR./config/<Plugin#id>/
depending on ConfigDir#sharedRoot()- ConfigurationLoader<CommentedConfigurationNode>
Must be annotated with
@DefaultConfig
. Used to inject a pre-generatedConfigurationLoader
for theFile
of the same annotation.- DefaultConfig (annotation on Path, ConfigurationLoader or File)
Used to inject the plugin’s specific configuration file:
<Plugin#id>.conf
- EventManager
Manages the registration of event handlers and the dispatching of events.
- File
Must be annotated with either
@DefaultConfig
or@ConfigDir
. Depending on the annotation given this will contain a file reference to the plugins default config file or the directory used for storing configuration files. However, Path (see below) should be preferred.- Game
The
Game
object is the core accessor of the SpongeAPI.- GameRegistry
Provides an easy way to retrieve types from a
Game
.- GuiceObjectMapperFactory
A tool provided by Configurate to allow easier mapping of objects to configuration nodes. See Serializing Objects for usage.
- Injector
com.google.inject.Injector
is available from Guice, it is the injector that was used to inject your plugin’s dependencies. You can use it to create a child injector with your own module in order to inject your own classes with either the Sponge provided dependencies listed on this page, or configure your own classes- Logger
Used to identify the plugin from which logged messages are sent.
- Path
Must be annotated with either
@DefaultConfig
or@ConfigDir
. Depending on the annotation given this will contain a path reference to the plugins default config file or the directory used for storing configuration files.- PluginContainer
A Plugin class wrapper, used to retrieve information from the annotation for easier use.
- PluginManager
Manages the plugins loaded by the implementation. Can retrieve another plugin’s
PluginContainer
.
Injection Examples
There are a few references which are difficult to get - or, in some cases, impossible - without injection. While these may not be absolutely vital to every plugin, they’re quite frequently used.
Note
Remember that it’s almost always best practice to inject your objects within the main class, as it’s instantiated with the Guice injector when the plugin is loaded.
Logger
Tip
View Logging and Debugging for a complete guide, specifically for the Logger.
Game
The Game
object is the opening for many of the internal functions of the SpongeAPI, from the EventManager
to the
Server and even the Sync/Async Scheduler.
While it is entirely possible to retrieve the Game
object through Sponge.getGame()
, it is commonly obtained
through an injection.
Example - Field
import com.google.inject.Inject;
import org.spongepowered.api.Game;
@Inject
private Game game;
Example - Method
private Game game;
@Inject
private void setGame(Game game) {
this.game = game;
}
Example - Constructor
For the purpose of this tutorial, «Apple» is the class name.
private Game game;
@Inject
public Apple(Game game) {
this.game = game;
}
Config Directory
The recommended way to obtain your config file is through Guice, along with the ConfigDir annotation.
Tip
If you set sharedRoot
to true
, your ConfigDir
will be the same directory which - potentially - houses
the configuration for other plugins. In most cases where grabbing the ConfigDir
is required, this should be
false
.
Example - Field
import org.spongepowered.api.config.ConfigDir;
import java.nio.file.Path;
@Inject
@ConfigDir(sharedRoot = false)
private Path configDir;
Example - Method
private Path configDir;
@Inject
@ConfigDir(sharedRoot = false)
private void setConfigDir(Path configDir) {
this.configDir = configDir;
}
Example - Constructor
For the purposes of this tutorial, «Orange» is the class name.
private Path configDir;
@Inject
public Orange(@ConfigDir(sharedRoot = false) Path configDir) {
this.configDir = configDir;
}
DefaultConfig
The way that @DefaultConfig
works is very similar to @ConfigDir
. The biggest difference is that
@DefaultConfig
refers to a specific file, whereas @ConfigDir
refers to a directory.
Tip
View Configuring Plugins for a complete guide, specifically for @DefaultConfig
.