Add MethodMetaData and ParameterMetaData for better type safety

src/de/steamwar/command/AbstractSWCommand.java

@@ -25,6 +25,7 @@ import java.lang.reflect.Parameter;
 import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiConsumer;
+import java.util.function.Function;
 import java.util.function.IntPredicate;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
@@ -133,49 +134,32 @@ public abstract class AbstractSWCommand<T> {
 
     private synchronized void initialize() {
         if (initialized) return;
-        List<Method> methods = methods();
+        List<Method> methods = methods().stream()
+                .filter(this::validateMethod)
+                .collect(Collectors.toList());
         for (Method method : methods) {
             Cached cached = method.getAnnotation(Cached.class);
-            addMapper(Mapper.class, method, i -> i == 0, false, AbstractTypeMapper.class, (anno, typeMapper) -> {
+            addMapper(Mapper.class, method, (anno, typeMapper) -> {
                 TabCompletionCache.add(typeMapper, cached);
-                if (anno.local()) {
+                (anno.local() ? ((Map) localTypeMapper) : SWCommandUtils.getMAPPER_FUNCTIONS()).put(anno.value(), typeMapper);
-                    localTypeMapper.putIfAbsent(anno.value(), (AbstractTypeMapper<T, ?>) typeMapper);
-                } else {
-                    SWCommandUtils.getMAPPER_FUNCTIONS().putIfAbsent(anno.value(), typeMapper);
-                }
             });
-            addMapper(ClassMapper.class, method, i -> i == 0, false, AbstractTypeMapper.class, (anno, typeMapper) -> {
+            addMapper(ClassMapper.class, method, (anno, typeMapper) -> {
                 TabCompletionCache.add(typeMapper, cached);
-                if (anno.local()) {
+                (anno.local() ? ((Map) localTypeMapper) : SWCommandUtils.getMAPPER_FUNCTIONS()).put(anno.value().getName(), typeMapper);
-                    localTypeMapper.putIfAbsent(anno.value().getTypeName(), (AbstractTypeMapper<T, ?>) typeMapper);
-                } else {
-                    SWCommandUtils.getMAPPER_FUNCTIONS().putIfAbsent(anno.value().getTypeName(), typeMapper);
-                }
             });
-            addValidator(Validator.class, method, i -> i == 0, false, AbstractValidator.class, (anno, validator) -> {
+            addValidator(Validator.class, method, (anno, validator) -> {
-                if (anno.local()) {
+                (anno.local() ? ((Map) localValidators) : SWCommandUtils.getVALIDATOR_FUNCTIONS()).put(anno.value(), validator);
-                    localValidators.putIfAbsent(anno.value(), (AbstractValidator<T, ?>) validator);
-                } else {
-                    SWCommandUtils.getVALIDATOR_FUNCTIONS().putIfAbsent(anno.value(), validator);
-                }
             });
-            addValidator(ClassValidator.class, method, i -> i == 0, false, AbstractValidator.class, (anno, validator) -> {
+            addValidator(ClassValidator.class, method, (anno, validator) -> {
-                if (anno.local()) {
+                (anno.local() ? ((Map) localValidators) : SWCommandUtils.getVALIDATOR_FUNCTIONS()).put(anno.value().getName(), validator);
-                    localValidators.putIfAbsent(anno.value().getTypeName(), (AbstractValidator<T, ?>) validator);
-                } else {
-                    SWCommandUtils.getVALIDATOR_FUNCTIONS().putIfAbsent(anno.value().getTypeName(), validator);
-                }
             });
         }
         for (Method method : methods) {
-            add(Register.class, method, i -> i > 0, true, null, (anno, parameters) -> {
+            add(Register.class, method, true, (anno, parameters) -> {
                 for (int i = 1; i < parameters.length; i++) {
                     Parameter parameter = parameters[i];
                     Class<?> clazz = parameter.getType();
-                    if (parameter.isVarArgs() && i == parameters.length - 1) {
+                    if (parameter.isVarArgs()) clazz = clazz.getComponentType();
-                        clazz = parameter.getType().getComponentType();
-                    }
-                    checkAnnotationApplicability(parameter, clazz);
                     Mapper mapper = parameter.getAnnotation(Mapper.class);
                     if (clazz.isEnum() && mapper == null && !SWCommandUtils.getMAPPER_FUNCTIONS().containsKey(clazz.getTypeName())) {
                         continue;
@@ -201,12 +185,42 @@ public abstract class AbstractSWCommand<T> {
         initialized = true;
     }
 
-    private void checkAnnotationApplicability(Parameter parameter, Class<?> clazz) {
+    private boolean validateMethod(Method method) {
-        Annotation[] annotations = parameter.getAnnotations();
+        if (!checkType(method.getAnnotations(), method.getReturnType(), annotation -> {
+            MethodMetaData methodMetaData = annotation.annotationType().getAnnotation(MethodMetaData.class);
+            if (methodMetaData == null) return null;
+            if (method.getParameterCount() > methodMetaData.maxParameterCount()) {
+                return new Class[0];
+            }
+            if (method.getParameterCount() < methodMetaData.minParameterCount()) {
+                return new Class[0];
+            }
+            return methodMetaData.possibleReturnTypes();
+        }, "The method '" + method + "'")) {
+            return false;
+        }
+        boolean valid = true;
+        for (Parameter parameter : method.getParameters()) {
+            Class<?> type = parameter.getType();
+            if (parameter.isVarArgs()) {
+                type = type.getComponentType();
+            }
+            if (!checkType(parameter.getAnnotations(), type, annotation -> {
+                ParameterMetaData parameterMetaData = annotation.annotationType().getAnnotation(ParameterMetaData.class);
+                if (parameterMetaData == null) return null;
+                return parameterMetaData.possibleTypes();
+            }, "The parameter '" + parameter + "'")) {
+                valid = false;
+            }
+        }
+        return valid;
+    }
+
+    private boolean checkType(Annotation[] annotations, Class<?> clazz, Function<Annotation, Class<?>[]> toApplicableTypes, String warning) {
+        boolean valid = true;
         for (Annotation annotation : annotations) {
-            ApplicableTypes applicableTypes = annotation.annotationType().getAnnotation(ApplicableTypes.class);
+            Class<?>[] types = toApplicableTypes.apply(annotation);
-            if (applicableTypes == null) continue;
+            if (types == null) continue;
-            Class<?>[] types = applicableTypes.value();
             boolean applicable = false;
             for (Class<?> type : types) {
                 if (type.isAssignableFrom(clazz)) {
@@ -215,33 +229,27 @@ public abstract class AbstractSWCommand<T> {
                 }
             }
             if (!applicable) {
-                commandSystemWarning(() -> "The parameter '" + parameter.toString() + "' is using an unsupported annotation of type '" + annotation.annotationType().getName() + "'");
+                commandSystemWarning(() -> warning + " is using an unsupported annotation of type '" + annotation.annotationType().getName() + "'");
+                valid = false;
             }
         }
+        return valid;
     }
 
-    private <T extends Annotation> void add(Class<T> annotation, Method method, IntPredicate parameterTester, boolean firstParameter, Class<?> returnType, BiConsumer<T, Parameter[]> consumer) {
+    private <T extends Annotation> void add(Class<T> annotation, Method method, boolean firstParameter, BiConsumer<T, Parameter[]> consumer) {
         T[] anno = SWCommandUtils.getAnnotation(method, annotation);
         if (anno == null || anno.length == 0) return;
 
         Parameter[] parameters = method.getParameters();
-        if (!parameterTester.test(parameters.length)) {
-            commandSystemWarning(() -> "The method '" + method.toString() + "' is lacking parameters or has too many");
-            return;
-        }
         if (firstParameter && !clazz.isAssignableFrom(parameters[0].getType())) {
             commandSystemWarning(() -> "The method '" + method.toString() + "' is lacking the first parameter of type '" + clazz.getTypeName() + "'");
             return;
         }
-        if (returnType != null && !returnType.isAssignableFrom(method.getReturnType())) {
-            commandSystemWarning(() -> "The method '" + method.toString() + "' is lacking the desired return type '" + returnType.getTypeName() + "'");
-            return;
-        }
         Arrays.stream(anno).forEach(t -> consumer.accept(t, parameters));
     }
 
-    private <T extends Annotation> void addMapper(Class<T> annotation, Method method, IntPredicate parameterTester, boolean firstParameter, Class<?> returnType, BiConsumer<T, AbstractTypeMapper<?, ?>> consumer) {
+    private <T extends Annotation> void addMapper(Class<T> annotation, Method method, BiConsumer<T, AbstractTypeMapper<?, ?>> consumer) {
-        add(annotation, method, parameterTester, firstParameter, returnType, (anno, parameters) -> {
+        add(annotation, method, false, (anno, parameters) -> {
             try {
                 method.setAccessible(true);
                 consumer.accept(anno, (AbstractTypeMapper<T, ?>) method.invoke(this));
@@ -251,8 +259,8 @@ public abstract class AbstractSWCommand<T> {
         });
     }
 
-    private <T extends Annotation> void addValidator(Class<T> annotation, Method method, IntPredicate parameterTester, boolean firstParameter, Class<?> returnType, BiConsumer<T, AbstractValidator<T, ?>> consumer) {
+    private <T extends Annotation> void addValidator(Class<T> annotation, Method method, BiConsumer<T, AbstractValidator<T, ?>> consumer) {
-        add(annotation, method, parameterTester, firstParameter, returnType, (anno, parameters) -> {
+        add(annotation, method, false, (anno, parameters) -> {
             try {
                 method.setAccessible(true);
                 consumer.accept(anno, (AbstractValidator<T, ?>) method.invoke(this));
@@ -287,6 +295,7 @@ public abstract class AbstractSWCommand<T> {
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.METHOD})
     @Repeatable(Register.Registeres.class)
+    @MethodMetaData(possibleReturnTypes = void.class, minParameterCount = 1)
     protected @interface Register {
 
         /**
@@ -303,6 +312,7 @@ public abstract class AbstractSWCommand<T> {
 
         @Retention(RetentionPolicy.RUNTIME)
         @Target({ElementType.METHOD})
+        @MethodMetaData(possibleReturnTypes = void.class, minParameterCount = 1)
         @interface Registeres {
             Register[] value();
         }
@@ -310,6 +320,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER, ElementType.METHOD})
+    @MethodMetaData(possibleReturnTypes = AbstractTypeMapper.class, minParameterCount = 0, maxParameterCount = 0)
     protected @interface Mapper {
         String value();
 
@@ -318,6 +329,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.METHOD})
+    @MethodMetaData(possibleReturnTypes = AbstractTypeMapper.class, minParameterCount = 0, maxParameterCount = 0)
     protected @interface ClassMapper {
         Class<?> value();
 
@@ -326,6 +338,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.METHOD})
+    @MethodMetaData(possibleReturnTypes = AbstractTypeMapper.class, minParameterCount = 0, maxParameterCount = 0)
     protected @interface Cached {
         long cacheDuration() default 5;
         TimeUnit timeUnit() default TimeUnit.SECONDS;
@@ -334,6 +347,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER, ElementType.METHOD})
+    @MethodMetaData(possibleReturnTypes = AbstractValidator.class, minParameterCount = 0, maxParameterCount = 0)
     protected @interface Validator {
         String value() default "";
 
@@ -342,6 +356,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.METHOD})
+    @MethodMetaData(possibleReturnTypes = AbstractValidator.class, minParameterCount = 0, maxParameterCount = 0)
     protected @interface ClassValidator {
         Class<?> value();
 
@@ -352,7 +367,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER})
-    @ApplicableTypes({String.class, int.class, Integer.class, boolean.class, Boolean.class})
+    @ParameterMetaData(possibleTypes = {String.class, int.class, Integer.class, long.class, Long.class, boolean.class, Boolean.class})
     protected @interface StaticValue {
         String[] value();
 
@@ -409,13 +424,13 @@ public abstract class AbstractSWCommand<T> {
      */
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER})
-    @ApplicableTypes({String.class})
+    @ParameterMetaData(possibleTypes = {String.class})
     protected @interface Quotable {
     }
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER})
-    @ApplicableTypes({int.class, Integer.class, long.class, Long.class, float.class, Float.class, double.class, Double.class})
+    @ParameterMetaData(possibleTypes = {int.class, Integer.class, long.class, Long.class, float.class, Float.class, double.class, Double.class})
     protected @interface Min {
         int intValue() default Integer.MIN_VALUE;
         long longValue() default Long.MIN_VALUE;
@@ -427,7 +442,7 @@ public abstract class AbstractSWCommand<T> {
 
     @Retention(RetentionPolicy.RUNTIME)
     @Target({ElementType.PARAMETER})
-    @ApplicableTypes({int.class, Integer.class, long.class, Long.class, float.class, Float.class, double.class, Double.class})
+    @ParameterMetaData(possibleTypes = {int.class, Integer.class, long.class, Long.class, float.class, Float.class, double.class, Double.class})
     protected @interface Max {
         int intValue() default Integer.MAX_VALUE;
         long longValue() default Long.MAX_VALUE;

src/de/steamwar/command/MethodMetaData.java

@@ -0,0 +1,33 @@
+/*
+ * 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 java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.ANNOTATION_TYPE)
+@interface MethodMetaData {
+    Class<?>[] possibleReturnTypes();
+    int minParameterCount() default 0;
+    int maxParameterCount() default Integer.MAX_VALUE;
+}

src/de/steamwar/command/ParameterMetaData.java

@@ -26,6 +26,6 @@ import java.lang.annotation.Target;
 
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.ANNOTATION_TYPE)
-@interface ApplicableTypes {
+@interface ParameterMetaData {
-    Class<?>[] value();
+    Class<?>[] possibleTypes();
 }