src/de/steamwar/command/AbstractSWCommand.java

@@ -183,7 +183,7 @@ public abstract class AbstractSWCommand<T> {
 
     private boolean validateMethod(Method method) {
         if (!checkType(method.getAnnotations(), method.getReturnType(), annotation -> {
-            MetaData.Method methodMetaData = annotation.annotationType().getAnnotation(MetaData.Method.class);
+            CommandMetaData.Method methodMetaData = annotation.annotationType().getAnnotation(CommandMetaData.Method.class);
             if (methodMetaData == null) return null;
             if (method.getParameterCount() > methodMetaData.maxParameterCount() || method.getParameterCount() < methodMetaData.minParameterCount()) return new Class[0];
             return methodMetaData.value();
@@ -193,7 +193,7 @@ public abstract class AbstractSWCommand<T> {
             Class<?> type = parameter.getType();
             if (parameter.isVarArgs()) type = type.getComponentType();
             if (!checkType(parameter.getAnnotations(), type, annotation -> {
-                MetaData.Parameter parameterMetaData = annotation.annotationType().getAnnotation(MetaData.Parameter.class);
+                CommandMetaData.Parameter parameterMetaData = annotation.annotationType().getAnnotation(CommandMetaData.Parameter.class);
                 if (parameterMetaData == null) return null;
                 return parameterMetaData.value();
             }, "The parameter '" + parameter + "'")) valid = false;
@@ -269,7 +269,7 @@ public abstract class AbstractSWCommand<T> {
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.METHOD})
     @Repeatable(Register.Registeres.class)
-    @MetaData.Method(value = void.class, minParameterCount = 1)
+    @CommandMetaData.Method(value = void.class, minParameterCount = 1)
     protected @interface Register {
 
         /**
@@ -286,7 +286,7 @@ public abstract class AbstractSWCommand<T> {
 
         @Retention(RetentionPolicy.RUNTIME)
         @Target({ElementType.METHOD})
-        @MetaData.Method(value = void.class, minParameterCount = 1)
+        @CommandMetaData.Method(value = void.class, minParameterCount = 1)
         @interface Registeres {
             Register[] value();
         }
@@ -294,7 +294,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER, ElementType.METHOD})
-    @MetaData.Method(value = AbstractTypeMapper.class, maxParameterCount = 0)
+    @CommandMetaData.Method(value = AbstractTypeMapper.class, maxParameterCount = 0)
     protected @interface Mapper {
         String value();
 
@@ -303,7 +303,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.METHOD})
-    @MetaData.Method(value = AbstractTypeMapper.class, maxParameterCount = 0)
+    @CommandMetaData.Method(value = AbstractTypeMapper.class, maxParameterCount = 0)
     protected @interface ClassMapper {
         Class<?> value();
 
@@ -312,7 +312,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.METHOD})
-    @MetaData.Method(value = AbstractTypeMapper.class, maxParameterCount = 0)
+    @CommandMetaData.Method(value = AbstractTypeMapper.class, maxParameterCount = 0)
     protected @interface Cached {
         long cacheDuration() default 5;
         TimeUnit timeUnit() default TimeUnit.SECONDS;
@@ -321,7 +321,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER, ElementType.METHOD})
-    @MetaData.Method(value = AbstractValidator.class, maxParameterCount = 0)
+    @CommandMetaData.Method(value = AbstractValidator.class, maxParameterCount = 0)
     protected @interface Validator {
         String value() default "";
 
@@ -330,7 +330,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.METHOD})
-    @MetaData.Method(value = AbstractValidator.class, maxParameterCount = 0)
+    @CommandMetaData.Method(value = AbstractValidator.class, maxParameterCount = 0)
     protected @interface ClassValidator {
         Class<?> value();
 
@@ -341,7 +341,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER})
-    @MetaData.Parameter({String.class, int.class, Integer.class, long.class, Long.class, boolean.class, Boolean.class})
+    @CommandMetaData.Parameter({String.class, int.class, Integer.class, long.class, Long.class, boolean.class, Boolean.class})
     protected @interface StaticValue {
         String[] value();
 
@@ -376,6 +376,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER})
+    @CommandMetaData.ImplicitValidator(handler = ImplicitTypeValidators.ErrorMessageValidator.class, order = 1)
     protected @interface ErrorMessage {
         /**
          * Error message to be displayed when the parameter is invalid.
@@ -398,13 +399,14 @@ public abstract class AbstractSWCommand<T> {
      */
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER})
-    @MetaData.Parameter({String.class})
+    @CommandMetaData.Parameter({String.class})
     protected @interface Quotable {
     }
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER})
-    @MetaData.Parameter({int.class, Integer.class, long.class, Long.class, float.class, Float.class, double.class, Double.class})
+    @CommandMetaData.Parameter({int.class, Integer.class, long.class, Long.class, float.class, Float.class, double.class, Double.class})
+    @CommandMetaData.ImplicitValidator(handler = ImplicitTypeValidators.MinValidator.class, order = 2)
     protected @interface Min {
         int intValue() default Integer.MIN_VALUE;
         long longValue() default Long.MIN_VALUE;
@@ -416,7 +418,8 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER})
-    @MetaData.Parameter({int.class, Integer.class, long.class, Long.class, float.class, Float.class, double.class, Double.class})
+    @CommandMetaData.Parameter({int.class, Integer.class, long.class, Long.class, float.class, Float.class, double.class, Double.class})
+    @CommandMetaData.ImplicitValidator(handler = ImplicitTypeValidators.MaxValidator.class, order = 2)
     protected @interface Max {
         int intValue() default Integer.MAX_VALUE;
         long longValue() default Long.MAX_VALUE;

src/de/steamwar/command/AbstractTypeMapper.java

@@ -25,6 +25,8 @@ public interface AbstractTypeMapper<K, T> extends AbstractValidator<K, T> {
     /**
      * The CommandSender can be null!
      */
+    // TODO: Change the 'previousArguments' to List<Object> or something like that
+    // TODO: Change T return value to Pair<T, Boolean> or something like that. This would make OptionalValue easier to implement as the Boolean would indicate if s should be consumed or not
     T map(K sender, String[] previousArguments, String s);
 
     @Override

src/de/steamwar/command/CommandMetaData.java

@@ -24,8 +24,11 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-@interface MetaData {
+public @interface CommandMetaData {
 
+    /**
+     * This annotation is only for internal use.
+     */
     @Retention(RetentionPolicy.RUNTIME)
     @Target(ElementType.ANNOTATION_TYPE)
     @interface Method {
@@ -34,9 +37,33 @@ import java.lang.annotation.Target;
         int maxParameterCount() default Integer.MAX_VALUE;
     }
 
+    /**
+     * This annotation denotes what types are allowed as parameter types the annotation annotated with can use.
+     */
     @Retention(RetentionPolicy.RUNTIME)
     @Target(ElementType.ANNOTATION_TYPE)
     @interface Parameter {
         Class<?>[] value();
     }
+
+    /**
+     * This annotation can be used in conjunction with a class that implement {@link AbstractValidator} to
+     * create custom validator short hands for commands. The validator class itself should contain a constructor
+     * with two parameters the first is the annotation this annotation is used on and the second is of type {@link Class}.
+     */
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target(ElementType.ANNOTATION_TYPE)
+    @interface ImplicitValidator {
+        /**
+         * The validator class that should be used.
+         */
+        Class<?> handler();
+
+        /**
+         * Defines when this validator should be processed. Negative numbers denote that this will be
+         * processed before {@link AbstractSWCommand.Validator} and positive numbers
+         * denote that this will be processed after {@link AbstractSWCommand.Validator}.
+         */
+        int order();
+    }
 }

src/de/steamwar/command/CommandPart.java

@@ -192,4 +192,8 @@ class CommandPart<T> {
         }
         return new CheckArgumentResult(true, value);
     }
+
+    public Class<?> getType() {
+        return varArgType != null ? varArgType : parameter.getType();
+    }
 }

src/de/steamwar/command/ImplicitTypeValidators.java

@@ -0,0 +1,102 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2022  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 lombok.experimental.UtilityClass;
+
+import java.lang.reflect.Array;
+import java.util.function.Function;
+
+@UtilityClass
+public class ImplicitTypeValidators {
+
+    public static class ErrorMessageValidator<T> implements AbstractValidator<T, Object> {
+
+        private AbstractSWCommand.ErrorMessage errorMessage;
+
+        public ErrorMessageValidator(AbstractSWCommand.ErrorMessage errorMessage, Class<?> type) {
+            this.errorMessage = errorMessage;
+        }
+
+        @Override
+        public boolean validate(T sender, Object value, MessageSender messageSender) {
+            if (value == null) messageSender.send(errorMessage.value());
+            if (!errorMessage.allowEAs() && value != null && value.getClass().isArray() && Array.getLength(value) == 0) {
+                messageSender.send(errorMessage.value());
+                return false;
+            }
+            return value != null;
+        }
+    }
+
+    public static class MinValidator<T> implements AbstractValidator<T, Number> {
+
+        private int value;
+        private Function<Number, Number> comparator;
+
+        public MinValidator(AbstractSWCommand.Min min, Class<?> clazz) {
+            this.value = min.inclusive() ? 0 : 1;
+
+            if (clazz == int.class || clazz == Integer.class) {
+                comparator = number -> Integer.compare(number.intValue(), min.intValue());
+            } else if (clazz == long.class || clazz == Long.class) {
+                comparator = number -> Long.compare(number.longValue(), min.longValue());
+            } else if (clazz == float.class || clazz == Float.class) {
+                comparator = number -> Float.compare(number.floatValue(), min.floatValue());
+            } else if (clazz == double.class || clazz == Double.class) {
+                comparator = number -> Double.compare(number.doubleValue(), min.doubleValue());
+            } else {
+                throw new IllegalArgumentException("Min annotation is not supported for " + clazz);
+            }
+        }
+
+        @Override
+        public boolean validate(T sender, Number value, MessageSender messageSender) {
+            return (comparator.apply(value).intValue()) >= this.value;
+        }
+    }
+
+    public static class MaxValidator<T> implements AbstractValidator<T, Number> {
+
+        private int value;
+        private Function<Number, Number> comparator;
+
+        public MaxValidator(AbstractSWCommand.Max max, Class<?> clazz) {
+            this.value = max.inclusive() ? 0 : -1;
+
+            if (clazz == int.class || clazz == Integer.class) {
+                comparator = number -> Integer.compare(number.intValue(), max.intValue());
+            } else if (clazz == long.class || clazz == Long.class) {
+                comparator = number -> Long.compare(number.longValue(), max.longValue());
+            } else if (clazz == float.class || clazz == Float.class) {
+                comparator = number -> Float.compare(number.floatValue(), max.floatValue());
+            } else if (clazz == double.class || clazz == Double.class) {
+                comparator = number -> Double.compare(number.doubleValue(), max.doubleValue());
+            } else {
+                throw new IllegalArgumentException("Max annotation is not supported for " + clazz);
+            }
+        }
+
+        @Override
+        public boolean validate(T sender, Number value, MessageSender messageSender) {
+            return (comparator.apply(value).intValue()) <= this.value;
+        }
+    }
+}

src/de/steamwar/command/SubCommand.java

@@ -19,10 +19,13 @@
 
 package de.steamwar.command;
 
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Parameter;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
@@ -142,22 +145,16 @@ public class SubCommand<T> {
             AbstractValidator<T, Object> validator = (AbstractValidator<T, Object>) SWCommandUtils.getValidator(parameter, localValidator);
             Class<?> varArgType = parameter.isVarArgs() ? parameter.getType().getComponentType() : null;
             AbstractSWCommand.OptionalValue optionalValue = parameter.getAnnotation(AbstractSWCommand.OptionalValue.class);
-            AbstractSWCommand.Min min = parameter.getAnnotation(AbstractSWCommand.Min.class);
-            AbstractSWCommand.Max max = parameter.getAnnotation(AbstractSWCommand.Max.class);
 
             CommandPart<T> commandPart = new CommandPart<>(command, typeMapper, varArgType, optionalValue != null ? optionalValue.value() : null, parameter, i);
             commandPart.setOnlyUseIfNoneIsGiven(optionalValue != null && optionalValue.onlyUINIG());
             if (parameter.getAnnotation(AbstractSWCommand.Quotable.class) == null) {
                 commandPart.addValidator((AbstractValidator<T, Object>) STRING_SPACE_FILTER);
             }
+            handleImplicitTypeValidator(parameter, commandPart, true);
             commandPart.addValidator(validator);
             commandPart.addValidator((AbstractValidator<T, Object>) SWCommandUtils.getErrorMessage(parameter));
-            if (min != null) {
-                commandPart.addValidator((AbstractValidator<T, Object>) createMinValidator(varArgType != null ? varArgType : parameter.getType(), min));
-            }
-            if (max != null) {
-                commandPart.addValidator((AbstractValidator<T, Object>) createMaxValidator(varArgType != null ? varArgType : parameter.getType(), max));
-            }
+            handleImplicitTypeValidator(parameter, commandPart, false);
             if (parameter.getAnnotation(AbstractSWCommand.AllowNull.class) == null) {
                 commandPart.addValidator((AbstractValidator<T, Object>) NULL_FILTER);
             }
@@ -172,6 +169,41 @@ public class SubCommand<T> {
         return first;
     }
 
+    private static <T> void handleImplicitTypeValidator(Parameter parameter, CommandPart<T> commandPart, boolean beforeValidatorAnnotation) {
+        Annotation[] annotations = parameter.getAnnotations();
+        Map<Integer, List<AbstractValidator<T, Object>>> validators = new HashMap<>();
+        for (Annotation annotation : annotations) {
+            CommandMetaData.ImplicitValidator implicitValidator = annotation.annotationType().getAnnotation(CommandMetaData.ImplicitValidator.class);
+            if (implicitValidator == null) continue;
+            if (beforeValidatorAnnotation && implicitValidator.order() >= 0) continue;
+            if (!beforeValidatorAnnotation && implicitValidator.order() <= 0) continue;
+            Class<?> clazz = implicitValidator.handler();
+            if (!AbstractValidator.class.isAssignableFrom(clazz)) continue;
+            Constructor<?>[] constructors = clazz.getConstructors();
+            if (constructors.length != 1) continue;
+            Constructor<?> constructor = constructors[0];
+            Class<?>[] parameterTypes = constructor.getParameterTypes();
+            if (parameterTypes.length != 2) continue;
+            AbstractValidator<T, Object> validator;
+            if (!annotation.annotationType().isAssignableFrom(parameterTypes[0])) continue;
+            if (!Class.class.isAssignableFrom(parameterTypes[1])) continue;
+            try {
+                validator = (AbstractValidator<T, Object>) constructor.newInstance(annotation, commandPart.getType());
+            } catch (InstantiationException | IllegalAccessException | InvocationTargetException e) {
+                throw new RuntimeException(e);
+            }
+            validators.computeIfAbsent(implicitValidator.order(), integer -> new ArrayList<>()).add(validator);
+        }
+        List<Integer> keys = new ArrayList<>(validators.keySet());
+        keys.sort(Integer::compareTo);
+        for (Integer key : keys) {
+            List<AbstractValidator<T, Object>> list = validators.get(key);
+            for (AbstractValidator<T, Object> validator : list) {
+                commandPart.addValidator(validator);
+            }
+        }
+    }
+
     private static final AbstractValidator<?, Object> NULL_FILTER = (sender, value, messageSender) -> value != null;
 
     private static final AbstractValidator<?, Object> STRING_SPACE_FILTER = (sender, value, messageSender) -> {