✨ Allow for recursive annotations (#97)

Co-authored-by: Mariell <proximyst@proximyst.com>

cloud-annotations/src/main/java/cloud/commandframework/annotations/AnnotationParser.java

@@ -51,11 +51,13 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Queue;
+import java.util.Set;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
@@ -106,16 +108,40 @@ public final class AnnotationParser<C> {
         ));
     }
 
+    @SuppressWarnings("unchecked")
+    static <A extends Annotation> @Nullable A getAnnotationRecursively(
+            final @NonNull Annotation[] annotations,
+            final @NonNull Class<A> clazz,
+            final @NonNull Set<Class<? extends Annotation>> checkedAnnotations
+    ) {
+        A innerCandidate = null;
+        for (final Annotation annotation : annotations) {
+            if (!checkedAnnotations.add(annotation.annotationType())) {
+                continue;
+            }
+            if (annotation.annotationType().equals(clazz)) {
+                return (A) annotation;
+            }
+            if (annotation.annotationType().getPackage().getName().startsWith("java.lang")) {
+                continue;
+            }
+            final A inner = getAnnotationRecursively(annotation.annotationType().getAnnotations(), clazz, checkedAnnotations);
+            if (inner != null) {
+                innerCandidate = inner;
+            }
+        }
+        return innerCandidate;
+    }
+
     static <A extends Annotation> @Nullable A getMethodOrClassAnnotation(
             final @NonNull Method method,
             final @NonNull Class<A> clazz
     ) {
-        if (method.isAnnotationPresent(clazz)) {
-            return method.getAnnotation(clazz);
-        } else if (method.getDeclaringClass().isAnnotationPresent(clazz)) {
-            return method.getDeclaringClass().getAnnotation(clazz);
+        A annotation = getAnnotationRecursively(method.getAnnotations(), clazz, new HashSet<>());
+        if (annotation == null) {
+            annotation = getAnnotationRecursively(method.getDeclaringClass().getAnnotations(), clazz, new HashSet<>());
         }
-        return null;
+        return annotation;
     }
 
     static <A extends Annotation> boolean methodOrClassHasAnnotation(

cloud-annotations/src/test/java/cloud/commandframework/annotations/AnnotationParserTest.java

@@ -32,6 +32,11 @@ import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
@@ -76,6 +81,34 @@ class AnnotationParserTest {
         Assertions.assertEquals(NAMED_SUGGESTIONS, manager.suggest(new TestCommandSender(), "namedsuggestions "));
     }
 
+    @Test
+    void testAnnotationResolver() throws Exception {
+        final Class<AnnotatedClass> annotatedClass = AnnotatedClass.class;
+        final Method annotatedMethod = annotatedClass.getDeclaredMethod("annotatedMethod");
+
+        System.out.println("Looking for @CommandDescription");
+        final CommandDescription commandDescription = AnnotationParser.getMethodOrClassAnnotation(annotatedMethod,
+                CommandDescription.class);
+        Assertions.assertNotNull(commandDescription);
+        Assertions.assertEquals("Hello World!", commandDescription.value());
+
+        System.out.println("Looking for @CommandPermission");
+        final CommandPermission commandPermission = AnnotationParser.getMethodOrClassAnnotation(annotatedMethod,
+                CommandPermission.class);
+        Assertions.assertNotNull(commandPermission);
+        Assertions.assertEquals("some.permission", commandPermission.value());
+
+        System.out.println("Looking for @CommandMethod");
+        final CommandMethod commandMethod = AnnotationParser.getMethodOrClassAnnotation(annotatedMethod,
+                CommandMethod.class);
+        Assertions.assertNotNull(commandMethod);
+        Assertions.assertEquals("method", commandMethod.value());
+
+        System.out.println("Looking for @Regex");
+        @SuppressWarnings("unused")
+        final Regex regex = AnnotationParser.getMethodOrClassAnnotation(annotatedMethod, Regex.class);
+    }
+
     @ProxiedBy("proxycommand")
     @CommandMethod("test|t literal <int> [string]")
     public void testCommand(
@@ -103,4 +136,37 @@ class AnnotationParserTest {
     ) {
     }
 
+
+    @CommandPermission("some.permission")
+    @Target(ElementType.METHOD)
+    @Retention(RetentionPolicy.RUNTIME)
+    private @interface AnnotatedAnnotation {
+    }
+
+
+    @Bad1
+    @CommandDescription("Hello World!")
+    private static class AnnotatedClass {
+
+        @CommandMethod("method")
+        @AnnotatedAnnotation
+        public static void annotatedMethod() {
+        }
+
+    }
+
+
+    @Bad2
+    @Target({ElementType.METHOD, ElementType.TYPE})
+    @Retention(RetentionPolicy.RUNTIME)
+    private @interface Bad1 {
+    }
+
+
+    @Bad1
+    @Target({ElementType.METHOD, ElementType.TYPE})
+    @Retention(RetentionPolicy.RUNTIME)
+    private @interface Bad2 {
+    }
+
 }