Working with Services

Pretty much everything (events, permissions, etc.) is handled through services. All services are accessed through the service manager:

game.getServiceManager().provide(EventManager.class);

If you need to get an object reference to something, just get it off the service manager.

Providing your own service

Your plugin can provide the implementation for a core interface like PermissionService, or for a custom interface that is not part of the Sponge API (e.g. economy, web server):

game.getServiceManager().setProvider(Object plugin, Class<T> service, T provider);

The provider object has to implement the service interface or class.

Designing the API this way makes Sponge extremely modular.

Note

Plugins should provide options to not install their providers if the plugin is not dedicated to a single function.

Example: Providing a simple economy service

The first step is optional, but recommended. You specify the public methods of your service class in an interface:

package test.service.economy;

import org.spongepowered.api.entity.player.Player;

public interface EconomyService
{
    public int getBalance(Player player);
    public void setBalance(Player player, int amount);
}

Now you can write the class that implements your interface:

package test.service.economy;

import java.util.HashMap;
import org.spongepowered.api.entity.player.Player;

public class SimpleEconomyService implements EconomyService
{
    HashMap<Player, Integer> balanceMap = new HashMap<Player, Integer>();

    @Override
    public int getBalance(Player player)
    {
            if(!balanceMap.containsKey(player)) return 0; //no stored balance for player

            else return balanceMap.get(player);
    }

    @Override
    public void setBalance(Player player, int amount)
    {
            balanceMap.put(player, amount);
    }
}

Now we can register a new instance of the class in the service manager. We are using the interface EconomyService.class as the service key.

This makes it possible for other plugin developers to write their own implementation of your service (that implements the interface) and replace your version.

game.getServiceManager().setProvider(yourPluginInstance, EconomyService.class, new SimpleEconomyService());

Other plugins can now access your service through the service manager:

game.getServiceManager().provide(EconomyService.class)

Tip

If you don’t want to use interfaces, just replace the service key with your class (SimpleEconomyService.class in the example).