FooRegistryModule.java

package org.spongepowered.cookbook.plugin;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.collect.ImmutableSet;
import org.spongepowered.api.registry.AdditionalCatalogRegistryModule;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;

public class FooRegistryModule implements AdditionalCatalogRegistryModule<FooType> {

    private final Map<String, FooType> fooTypeMap = new HashMap<>();

    @Override
    public void registerDefaults() {
        this.fooTypeMap.put("foo", FooTypes.FOO);
        this.fooTypeMap.put("bar", FooTypes.BAR);
        this.fooTypeMap.put("baz", FooTypes.BAZ);
    }

    @Override
    public void registerAdditionalCatalog(FooType extraCatalog) {
        checkArgument(!this.fooTypeMap.containsKey(checkNotNull(extraCatalog).getId().toLowerCase()));
        this.fooTypeMap.put(extraCatalog.getId().toLowerCase(), extraCatalog);
    }

    @Override
    public Optional<FooType> getById(String id) {
        return Optional.ofNullable(this.fooTypeMap.get(checkNotNull(id).toLowerCase()));
    }

    @Override
    public Collection<FooType> getAll() {
        return ImmutableSet.copyOf(this.fooTypeMap.values());
    }
}

FooType.java

package org.spongepowered.cookbook.plugin;

import static com.google.common.base.Preconditions.checkNotNull;

import org.spongepowered.api.CatalogType;
import org.spongepowered.api.util.annotation.CatalogedBy;

@CatalogedBy(FooTypes.class)
public class FooType implements CatalogType {

    private final String id;
    private final String name;

    public FooType(String id, String name) {
        this.id = checkNotNull(id);
        this.name = checkNotNull(name);
    }

    @Override
    public String getId() {
        return this.id;
    }

    @Override
    public String getName() {
        return this.name;
    }
}

FooTypes.java

package org.spongepowered.cookbook.plugin;

public final class FooTypes {

    public static final FooType FOO = new FooType("foo", "Foo");
    public static final FooType BAR = new FooType("bar", "Bar");
    public static final FooType BAZ = new FooType("baz", "Baz");

    private FooTypes() {
    }

}

plugin.java

package org.spongepowered.cookbook.plugin;

import org.spongepowered.api.Sponge;
import org.spongepowered.api.event.Listener;
import org.spongepowered.api.event.game.state.GameInitializationEvent;
import org.spongepowered.api.event.game.state.GamePreInitializationEvent;
import org.spongepowered.api.plugin.Plugin;

import javax.annotation.Resource;

@Plugin(id = "spongetest", name = "SpongeTest", version = "0.1")
@Resource
public class WorldsTest {


    @Listener
    public void onPreInit(GamePreInitializationEvent event) {
        Sponge.getRegistry().registerModule(FooType.class, new FooRegistryModule());
    }

    @Listener
    public void onInit(GameInitializationEvent event) {
        Sponge.getRegistry().register(FooType.class, new FooType("derp", "Derp"));
    }


}