SpigotCore_Main/src/de/steamwar/acommand/TestCommand.java

@@ -0,0 +1,82 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2020  SteamWar.de-Serverteam
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.acommand;
+
+import de.steamwar.command.SWCommand;
+import de.steamwar.command.TypeMapper;
+import org.bukkit.Material;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class TestCommand extends SWCommand {
+
+    public TestCommand() {
+        // Register this command as 'test'
+        super("test");
+    }
+
+    // One Help Command, the first Parameter should be some kind of CommandSender
+    // The second argument can only be a varArgs string of what arguments were tried to map
+    @Register(help = true)
+    public void testHelp(Player player, String... args) {
+        player.sendMessage("This is your help message");
+    }
+
+    // One Command, the first Parameter should be some kind of CommandSender
+    @Register
+    public void test(Player player) {
+
+    }
+
+    // Another Command, subCommands can be implemented with the Register Annotation,
+    // you can use custom Mappers by putting a Mapper Annotation on a Parameter
+    @Register({"two"})
+    public void testTwo(Player player, int i, @Mapper("solidMaterial") Material material) {
+
+    }
+
+    // Add Custom Mapper when this command is registered, all Mapper of you class will be
+    // created first and than the Commands. Do not use this mapper outside your class, as
+    // it can only create failures. Use on your own risk. Definition order should be considered.
+    @Mapper("solidMaterial")
+    public TypeMapper<Material> materialTypeMapper() {
+        List<String> tabCompletes = Arrays.stream(Material.values())
+                .filter(Material::isSolid)
+                .map(Material::name)
+                .map(String::toLowerCase)
+                .collect(Collectors.toList());
+        return new TypeMapper<Material>() {
+            @Override
+            public Material map(String[] previous, String s) {
+                return Material.valueOf(s.toUpperCase());
+            }
+
+            @Override
+            public List<String> tabCompletes(CommandSender commandSender, String[] previous, String s) {
+                return tabCompletes;
+            }
+        };
+    }
+
+}

SpigotCore_Main/src/de/steamwar/command/CommandParseException.java

@@ -0,0 +1,42 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2020  SteamWar.de-Serverteam
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.command;
+
+public class CommandParseException extends Exception {
+
+    public CommandParseException() {
+    }
+
+    public CommandParseException(String message) {
+        super(message);
+    }
+
+    public CommandParseException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public CommandParseException(Throwable cause) {
+        super(cause);
+    }
+
+    public CommandParseException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+}

SpigotCore_Main/src/de/steamwar/command/SWCommand.java

@@ -0,0 +1,224 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2020  SteamWar.de-Serverteam
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.command;
+
+import org.bukkit.Bukkit;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+
+import java.lang.annotation.*;
+import java.lang.reflect.Method;
+import java.lang.reflect.Parameter;
+import java.util.*;
+import java.util.function.BiConsumer;
+import java.util.function.IntPredicate;
+import java.util.logging.Level;
+
+public abstract class SWCommand {
+
+    private final Command command;
+    private final List<SubCommand> commandSet = new ArrayList<>();
+    private final List<SubCommand> commandHelpSet = new ArrayList<>();
+    private final Map<String, TypeMapper<?>> localTypeMapper = new HashMap<>();
+
+    protected SWCommand(String command) {
+        this(command, new String[0]);
+    }
+
+    protected SWCommand(String command, String... aliases) {
+        this.command = new Command(command, "", "/" + command, Arrays.asList(aliases)) {
+            @Override
+            public boolean execute(CommandSender sender, String alias, String[] args) {
+                for (SubCommand subCommand : commandSet) {
+                    if (subCommand.invoke(sender, args)) {
+                        return false;
+                    }
+                }
+                for (SubCommand subCommand : commandHelpSet) {
+                    if (subCommand.invoke(sender, args)) {
+                        return false;
+                    }
+                }
+                return false;
+            }
+
+            @Override
+            public List<String> tabComplete(CommandSender sender, String alias, String[] args) throws IllegalArgumentException {
+                List<String> strings = new ArrayList<>();
+                for (SubCommand subCommand : commandSet) {
+                    List<String> tabCompletes = subCommand.tabComplete(sender, args);
+                    if (tabCompletes != null) {
+                        strings.addAll(tabCompletes);
+                    }
+                }
+                strings = new ArrayList<>(strings);
+                for (int i = strings.size() - 1; i >= 0; i--) {
+                    if (!strings.get(i).toLowerCase().startsWith(args[args.length - 1].toLowerCase())) {
+                        strings.remove(i);
+                    }
+                }
+                return strings;
+            }
+        };
+        register();
+
+        for (Method method : getClass().getDeclaredMethods()) {
+            addMapper(Mapper.class, method, i -> i == 0, false, TypeMapper.class, (anno, typeMapper) -> {
+                if (anno.local()) {
+                    localTypeMapper.put(anno.value(), typeMapper);
+                } else {
+                    SWCommandUtils.addMapper(anno.value(), typeMapper);
+                }
+            });
+            addMapper(ClassMapper.class, method, i -> i == 0, false, TypeMapper.class, (anno, typeMapper) -> {
+                if (anno.local()) {
+                    localTypeMapper.put(anno.value().getTypeName(), typeMapper);
+                } else {
+                    SWCommandUtils.addMapper(anno.value().getTypeName(), typeMapper);
+                }
+            });
+            add(Register.class, method, i -> i > 0, true, null, (anno, parameters) -> {
+                if (!anno.help()) {
+                    return;
+                }
+                if (parameters.length != 2) {
+                    Bukkit.getLogger().log(Level.WARNING, "The method '" + method.toString() + "' is lacking parameters or has too many");
+                }
+                if (!parameters[parameters.length - 1].isVarArgs()) {
+                    Bukkit.getLogger().log(Level.WARNING, "The method '" + method.toString() + "' is lacking the varArgs parameters as last Argument");
+                }
+                if (parameters[parameters.length - 1].getType().getComponentType() != String.class) {
+                    Bukkit.getLogger().log(Level.WARNING, "The method '" + method.toString() + "' is lacking the varArgs parameters of type '" + String.class.getTypeName() + "' as last Argument");
+                    return;
+                }
+                commandHelpSet.add(new SubCommand(this, method, anno.value()));
+            });
+        }
+        for (Method method : getClass().getDeclaredMethods()) {
+            add(Register.class, method, i -> i > 0, true, null, (anno, parameters) -> {
+                if (anno.help()) {
+                    return;
+                }
+                for (int i = 1; i < parameters.length; i++) {
+                    Parameter parameter = parameters[i];
+                    Class<?> clazz = parameter.getType();
+                    if (parameter.isVarArgs() && i == parameters.length - 1) {
+                        clazz = parameter.getType().getComponentType();
+                    }
+                    Mapper mapper = parameter.getAnnotation(Mapper.class);
+                    if (clazz.isEnum() && mapper == null && !SWCommandUtils.MAPPER_FUNCTIONS.containsKey(clazz.getTypeName())) {
+                        continue;
+                    }
+                    String name = clazz.getTypeName();
+                    if (mapper != null) {
+                        name = mapper.value();
+                    }
+                    if (!SWCommandUtils.MAPPER_FUNCTIONS.containsKey(name)) {
+                        Bukkit.getLogger().log(Level.WARNING, "The parameter '" + parameter.toString() + "' is using an unsupported Mapper of type '" + name + "'");
+                        return;
+                    }
+                }
+                commandSet.add(new SubCommand(this, method, anno.value(), localTypeMapper));
+            });
+
+            this.commandSet.sort((o1, o2) -> {
+                int compare = Integer.compare(-o1.subCommand.length, -o2.subCommand.length);
+                if (compare != 0) {
+                    return compare;
+                } else {
+                    int i1 = o1.varArgType != null ? Integer.MAX_VALUE : o1.arguments.length;
+                    int i2 = o2.varArgType != null ? Integer.MAX_VALUE : o2.arguments.length;
+                    return Integer.compare(i1, i2);
+                }
+            });
+            commandHelpSet.sort(Comparator.comparingInt(o -> -o.subCommand.length));
+        }
+    }
+
+    private <T extends Annotation> void add(Class<T> annotation, Method method, IntPredicate parameterTester, boolean firstParameter, Class<?> returnType, BiConsumer<T, Parameter[]> consumer) {
+        T anno = SWCommandUtils.getAnnotation(method, annotation);
+        if (anno == null) {
+            return;
+        }
+
+        Parameter[] parameters = method.getParameters();
+        if (!parameterTester.test(parameters.length)) {
+            Bukkit.getLogger().log(Level.WARNING, "The method '" + method.toString() + "' is lacking parameters or has too many");
+            return;
+        }
+        if (firstParameter && !CommandSender.class.isAssignableFrom(parameters[0].getType())) {
+            Bukkit.getLogger().log(Level.WARNING, "The method '" + method.toString() + "' is lacking the first parameter of type '" + CommandSender.class.getTypeName() + "'");
+            return;
+        }
+        if (returnType != null && method.getReturnType() != returnType) {
+            Bukkit.getLogger().log(Level.WARNING, "The method '" + method.toString() + "' is lacking the desired return type '" + returnType.getTypeName() + "'");
+            return;
+        }
+        consumer.accept(anno, parameters);
+    }
+
+    private <T extends Annotation> void addMapper(Class<T> annotation, Method method, IntPredicate parameterTester, boolean firstParameter, Class<?> returnType, BiConsumer<T, TypeMapper<?>> consumer) {
+        add(annotation, method, parameterTester, firstParameter, returnType, (anno, parameters) -> {
+            try {
+                method.setAccessible(true);
+                Object object = method.invoke(this);
+                consumer.accept(anno, (TypeMapper<?>) object);
+            } catch (Exception e) {
+                throw new SecurityException(e.getMessage(), e);
+            }
+        });
+    }
+
+    protected void unregister() {
+        SWCommandUtils.knownCommandMap.remove(command.getName());
+        for (String alias : command.getAliases()) {
+            SWCommandUtils.knownCommandMap.remove(alias);
+        }
+        command.unregister(SWCommandUtils.commandMap);
+    }
+
+    protected void register() {
+        SWCommandUtils.commandMap.register("steamwar", this.command);
+    }
+
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target({ElementType.METHOD})
+    protected @interface Register {
+        String[] value() default {};
+
+        boolean help() default false;
+    }
+
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target({ElementType.PARAMETER, ElementType.METHOD})
+    protected @interface Mapper {
+        String value();
+
+        boolean local() default false;
+    }
+
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target({ElementType.METHOD})
+    protected @interface ClassMapper {
+        Class<?> value();
+
+        boolean local() default false;
+    }
+}

SpigotCore_Main/src/de/steamwar/command/SWCommandUtils.java

@@ -0,0 +1,185 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2020  SteamWar.de-Serverteam
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.command;
+
+import org.bukkit.Bukkit;
+import org.bukkit.GameMode;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandMap;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.SimpleCommandMap;
+import org.bukkit.entity.Player;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Array;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.*;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class SWCommandUtils {
+
+    private SWCommandUtils() {
+        throw new IllegalStateException("Utility Class");
+    }
+
+    static final Map<String, TypeMapper<?>> MAPPER_FUNCTIONS = new HashMap<>();
+
+    static final TypeMapper<?> ERROR_FUNCTION = createMapper(s -> {
+        throw new SecurityException();
+    }, s -> Collections.emptyList());
+
+    static final BiFunction<Class<Enum<?>>, String, Enum<?>> ENUM_MAPPER = (enumClass, s) -> {
+        Enum<?>[] enums = enumClass.getEnumConstants();
+        for (Enum<?> e : enums) {
+            if (e.name().equalsIgnoreCase(s)) return e;
+        }
+        return null;
+    };
+
+    static {
+        addMapper(boolean.class, Boolean.class, createMapper(Boolean::parseBoolean, s -> Arrays.asList("true", "false")));
+        addMapper(float.class, Float.class, createMapper(Float::parseFloat, numberCompleter(Float::parseFloat)));
+        addMapper(double.class, Double.class, createMapper(Double::parseDouble, numberCompleter(Double::parseDouble)));
+        addMapper(int.class, Integer.class, createMapper(Integer::parseInt, numberCompleter(Integer::parseInt)));
+        MAPPER_FUNCTIONS.put(String.class.getTypeName(), createMapper(s -> s, Collections::singletonList));
+        MAPPER_FUNCTIONS.put(Player.class.getTypeName(), createMapper(Bukkit::getPlayer, s -> Bukkit.getOnlinePlayers().stream().map(Player::getName).collect(Collectors.toList())));
+        MAPPER_FUNCTIONS.put(GameMode.class.getTypeName(), createMapper(s -> {
+            s = s.toLowerCase();
+            if (s.equals("s") || s.equals("survival") || s.equals("0")) return GameMode.SURVIVAL;
+            if (s.equals("c") || s.equals("creative") || s.equals("1")) return GameMode.CREATIVE;
+            if (s.equals("sp") || s.equals("spectator") || s.equals("3")) return GameMode.SPECTATOR;
+            if (s.equals("a") || s.equals("adventure") || s.equals("2")) return GameMode.ADVENTURE;
+            throw new SecurityException();
+        }, s -> Arrays.asList("s", "survival", "0", "c", "creative", "1", "sp", "specator", "3", "a", "adventure", "2")));
+    }
+
+    private static void addMapper(Class<?> clazz, Class<?> alternativeClazz, TypeMapper<?> mapper) {
+        MAPPER_FUNCTIONS.put(clazz.getTypeName(), mapper);
+        MAPPER_FUNCTIONS.put(alternativeClazz.getTypeName(), mapper);
+    }
+
+    static final CommandMap commandMap;
+    static final Map<String, Command> knownCommandMap;
+
+    static {
+        try {
+            final Field commandMapField = Bukkit.getServer().getClass().getDeclaredField("commandMap");
+            commandMapField.setAccessible(true);
+            commandMap = (CommandMap) commandMapField.get(Bukkit.getServer());
+        } catch (NoSuchFieldException | IllegalAccessException exception) {
+            Bukkit.shutdown();
+            throw new SecurityException("Oh shit. Commands cannot be registered.", exception);
+        }
+        try {
+            final Field knownCommandsField = SimpleCommandMap.class.getDeclaredField("knownCommands");
+            knownCommandsField.setAccessible(true);
+            knownCommandMap = (Map<String, Command>) knownCommandsField.get(commandMap);
+        } catch (NoSuchFieldException | IllegalAccessException exception) {
+            Bukkit.shutdown();
+            throw new SecurityException("Oh shit. Commands cannot be registered.", exception);
+        }
+    }
+
+    static Object[] generateArgumentArray(TypeMapper<?>[] parameters, String[] args, Class<?> varArgType, String[] subCommand) throws CommandParseException {
+        Object[] arguments = new Object[parameters.length + 1];
+        int index = 0;
+        while (index < subCommand.length) {
+            if (!args[index].equalsIgnoreCase(subCommand[index])) {
+                throw new CommandParseException();
+            }
+            index++;
+        }
+
+        if (varArgType != null && index > args.length - 1) {
+            Object varArgument = Array.newInstance(varArgType, 0);
+            arguments[arguments.length - 1] = varArgument;
+        } else {
+            for (int i = 0; i < parameters.length - (varArgType != null ? 1 : 0); i++) {
+                arguments[i + 1] = parameters[i].map(Arrays.copyOf(args, index), args[index]);
+                index++;
+                if (arguments[i + 1] == null) {
+                    throw new CommandParseException();
+                }
+            }
+
+            if (varArgType != null) {
+                int length = args.length - parameters.length - subCommand.length + 1;
+                Object varArgument = Array.newInstance(varArgType, length);
+                arguments[arguments.length - 1] = varArgument;
+
+                for (int i = 0; i < length; i++) {
+                    Object value = parameters[parameters.length - 1].map(Arrays.copyOf(args, index), args[index]);
+                    if (value == null) {
+                        throw new CommandParseException();
+                    }
+                    Array.set(varArgument, i, value);
+                    index++;
+                }
+            }
+        }
+        return arguments;
+    }
+
+    public static <T> void addMapper(Class<T> clazz, TypeMapper<T> mapper) {
+        addMapper(clazz.getTypeName(), mapper);
+    }
+
+    public static void addMapper(String name, TypeMapper<?> mapper) {
+        if (MAPPER_FUNCTIONS.containsKey(name)) return;
+        MAPPER_FUNCTIONS.put(name, mapper);
+    }
+
+    public static <T> TypeMapper<T> createMapper(Function<String, T> mapper, Function<String, List<String>> tabCompleter) {
+        return createMapper(mapper, (commandSender, s) -> tabCompleter.apply(s));
+    }
+
+    public static <T> TypeMapper<T> createMapper(Function<String, T> mapper, BiFunction<CommandSender, String, List<String>> tabCompleter) {
+        return new TypeMapper<T>() {
+            @Override
+            public T map(String[] previous, String s) {
+                return mapper.apply(s);
+            }
+
+            @Override
+            public List<String> tabCompletes(CommandSender commandSender, String[] previous, String s) {
+                return tabCompleter.apply(commandSender, s);
+            }
+        };
+    }
+
+    private static Function<String, List<String>> numberCompleter(Function<String, ?> mapper) {
+        return s -> {
+            try {
+                mapper.apply(s);
+                return Collections.singletonList(s);
+            } catch (Exception e) {
+                return Collections.emptyList();
+            }
+        };
+    }
+
+    static <T extends Annotation> T getAnnotation(Method method, Class<T> annotation) {
+        if (method.getAnnotations().length != 1) return null;
+        return method.getAnnotation(annotation);
+    }
+}

SpigotCore_Main/src/de/steamwar/command/SubCommand.java

@@ -0,0 +1,139 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2020  SteamWar.de-Serverteam
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.command;
+
+import org.bukkit.command.CommandSender;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Parameter;
+import java.util.*;
+import java.util.function.Function;
+
+class SubCommand {
+
+    private SWCommand swCommand;
+    private Method method;
+    String[] subCommand;
+    TypeMapper<?>[] arguments;
+    private Function<CommandSender, ?> commandSenderFunction;
+    Class<?> varArgType = null;
+
+    public SubCommand(SWCommand swCommand, Method method, String[] subCommand) {
+        this(swCommand, method, subCommand, new HashMap<>());
+    }
+
+    public SubCommand(SWCommand swCommand, Method method, String[] subCommand, Map<String, TypeMapper<?>> localTypeMapper) {
+        this.swCommand = swCommand;
+        this.method = method;
+
+        Parameter[] parameters = method.getParameters();
+        commandSenderFunction = sender -> parameters[0].getType().cast(sender);
+        this.subCommand = subCommand;
+
+        arguments = new TypeMapper[parameters.length - 1];
+        for (int i = 1; i < parameters.length; i++) {
+            Parameter parameter = parameters[i];
+            Class<?> clazz = parameter.getType();
+            if (parameter.isVarArgs()) {
+                clazz = clazz.getComponentType();
+                varArgType = clazz;
+            }
+
+            SWCommand.Mapper mapper = parameter.getAnnotation(SWCommand.Mapper.class);
+            if (clazz.isEnum() && mapper == null && !SWCommandUtils.MAPPER_FUNCTIONS.containsKey(clazz.getTypeName()) && !localTypeMapper.containsKey(clazz.getTypeName())) {
+                Class<Enum<?>> enumClass = (Class<Enum<?>>) clazz;
+                List<String> tabCompletes = new ArrayList<>();
+                for (Enum<?> enumConstant : enumClass.getEnumConstants()) {
+                    tabCompletes.add(enumConstant.name().toLowerCase());
+                }
+                arguments[i - 1] = SWCommandUtils.createMapper(s -> SWCommandUtils.ENUM_MAPPER.apply(enumClass, s), s -> tabCompletes);
+                continue;
+            }
+
+            String name = clazz.getTypeName();
+            if (mapper != null) {
+                name = mapper.value();
+            }
+            if (localTypeMapper.containsKey(name)) {
+                arguments[i - 1] = localTypeMapper.getOrDefault(name, SWCommandUtils.ERROR_FUNCTION);
+            } else {
+                arguments[i - 1] = SWCommandUtils.MAPPER_FUNCTIONS.getOrDefault(name, SWCommandUtils.ERROR_FUNCTION);
+            }
+        }
+    }
+
+    boolean invoke(CommandSender commandSender, String[] args) {
+        if (args.length < arguments.length + subCommand.length - (varArgType != null ? 1 : 0)) {
+            return false;
+        }
+        if (varArgType == null && args.length > arguments.length + subCommand.length) {
+            return false;
+        }
+        try {
+            Object[] objects = SWCommandUtils.generateArgumentArray(arguments, args, varArgType, subCommand);
+            objects[0] = commandSenderFunction.apply(commandSender);
+            method.setAccessible(true);
+            method.invoke(swCommand, objects);
+        } catch (IllegalAccessException | RuntimeException | InvocationTargetException e) {
+            throw new SecurityException(e.getMessage(), e);
+        } catch (CommandParseException e) {
+            return false;
+        }
+        return true;
+    }
+
+    List<String> tabComplete(CommandSender commandSender, String[] args) {
+        if (varArgType == null && args.length < arguments.length + subCommand.length - 1) {
+            return null;
+        }
+        List<String> argsList = new LinkedList<>(Arrays.asList(args));
+        for (String value : subCommand) {
+            String s = argsList.remove(0);
+            if (argsList.isEmpty()) return Collections.singletonList(value);
+            if (!value.equalsIgnoreCase(s)) return null;
+        }
+        for (TypeMapper<?> argument : arguments) {
+            String s = argsList.remove(0);
+            if (argsList.isEmpty()) return argument.tabCompletes(commandSender, Arrays.copyOf(args, args.length - 1), s);
+            try {
+                if (argument.map(Arrays.copyOf(args, argsList.size()), s) == null) {
+                    return null;
+                }
+            } catch (Exception e) {
+                return null;
+            }
+        }
+        if (varArgType != null && !argsList.isEmpty()) {
+            while (!argsList.isEmpty()) {
+                String s = argsList.remove(0);
+                if (argsList.isEmpty()) return arguments[arguments.length - 1].tabCompletes(commandSender, Arrays.copyOf(args, args.length - 1), s);
+                try {
+                    if (arguments[arguments.length - 1].map(Arrays.copyOf(args, argsList.size()), s) == null) {
+                        return null;
+                    }
+                } catch (Exception e) {
+                    return null;
+                }
+            }
+        }
+        return null;
+    }
+}

SpigotCore_Main/src/de/steamwar/command/TypeMapper.java

@@ -0,0 +1,30 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2020  SteamWar.de-Serverteam
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.command;
+
+import org.bukkit.command.CommandSender;
+
+import java.util.List;
+
+public interface TypeMapper<T> {
+    T map(String[] previousArguments, String s);
+
+    List<String> tabCompletes(CommandSender commandSender, String[] previousArguments, String s);
+}