import org.spongepowered.api.util.annotation.NonnullByDefault; //导入依赖的package包/类
/**
 * Attempt to extract a value for this element from the given arguments.
 * This method is expected to have no side-effects for the source, meaning
 * that executing it will not change the state of the {@link CommandSource}
 * in any way.
 *
 * @param source The source to parse for
 * @param args   the arguments
 * @return The extracted value
 * @throws ArgumentParseException if unable to extract a value
 */
@Override
@Nullable
@NonnullByDefault
protected Object parseValue(CommandSource source, CommandArgs args) throws ArgumentParseException {
	String type = args.next().toLowerCase();

	if (LoadedRegion.ChunkType.asMap().containsKey(type)) {
		if (source.hasPermission(String.format("%s.%s", Permissions.COMMAND_CREATE, type)))
			return LoadedRegion.ChunkType.asMap().get(type);
		else
			throw new ArgumentParseException(Text.of(TextColors.RED, String.format("You do not have permission to create %s chunks", type)), type, 0);
	} else {
		throw new ArgumentParseException(Text.of(TextColors.RED, "Chunk type does not exist."), type, 0);
	}
}
 

import org.spongepowered.api.util.annotation.NonnullByDefault; //导入依赖的package包/类
/**
 * Fetch completions for command arguments.
 *
 * @param src     The source requesting tab completions
 * @param args    The arguments currently provided
 * @param context The context to store state in
 * @return Any relevant completions
 */
@Override
@NonnullByDefault
public List<String> complete(CommandSource src, CommandArgs args, CommandContext context) {
	try {
		String type = args.peek().toLowerCase();
		return LoadedRegion.ChunkType.asMap().entrySet().stream()
			.filter(s -> s.getKey().startsWith(type))
			.filter(s -> Permissions.hasPermission(src, s.getKey()))
			.map(Map.Entry::getKey)
			.collect(Collectors.toList());
	} catch (ArgumentParseException e) {
		e.printStackTrace();
	}

	return Lists.newArrayList();
}