[AFP-91] 🎨 Create custom annotations & resolvers for 'ManagerController' (@asegers)

src/main/java/com/afp/ordermanagement/annotation/AccessToken.java

+package com.afp.ordermanagement.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.PARAMETER)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface AccessToken {
+}

src/main/java/com/afp/ordermanagement/annotation/AccessTokenResolver.java

+package com.afp.ordermanagement.annotation;
+
+import com.afp.ordermanagement.service.ManagerTokenVerifier;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.MethodParameter;
+import org.springframework.web.reactive.BindingContext;
+import org.springframework.web.reactive.result.method.HandlerMethodArgumentResolver;
+import org.springframework.web.server.ServerWebExchange;
+import reactor.core.publisher.Mono;
+
+public class AccessTokenResolver implements HandlerMethodArgumentResolver {
+    @Autowired
+    ManagerTokenVerifier managerTokenVerifier;
+
+    @Override
+    public boolean supportsParameter(MethodParameter methodParameter) {
+        boolean hasClassAnnotation = methodParameter.getDeclaringClass().isAnnotationPresent(AuthManagerController.class);
+        boolean hasMethodAnnotation = methodParameter.hasMethodAnnotation(AuthManagerResponse.class);
+        boolean hasParameterAnnotation = methodParameter.hasParameterAnnotation(AccessToken.class);
+        return (hasClassAnnotation || hasMethodAnnotation) && hasParameterAnnotation;
+    }
+
+    @Override
+    public Mono<Object> resolveArgument(MethodParameter methodParameter, BindingContext bindingContext, ServerWebExchange serverWebExchange) {
+        String accessToken = managerTokenVerifier.getTokenHeader(serverWebExchange);
+        return Mono.just(accessToken);
+    }
+}

src/main/java/com/afp/ordermanagement/annotation/AuthManagerController.java

+package com.afp.ordermanagement.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface AuthManagerController {
+}

src/main/java/com/afp/ordermanagement/annotation/AuthManagerResponse.java

+package com.afp.ordermanagement.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface AuthManagerResponse {
+}

src/main/java/com/afp/ordermanagement/annotation/ManagerPayload.java

+package com.afp.ordermanagement.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.PARAMETER)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface ManagerPayload {
+    String value() default "";
+    String pluck() default "";
+}

src/main/java/com/afp/ordermanagement/annotation/ManagerPayloadResolver.java

+package com.afp.ordermanagement.annotation;
+
+import com.afp.ordermanagement.model.Manager;
+import com.afp.ordermanagement.service.ManagerTokenVerifier;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.MethodParameter;
+import org.springframework.web.reactive.BindingContext;
+import org.springframework.web.reactive.result.method.HandlerMethodArgumentResolver;
+import org.springframework.web.server.ServerWebExchange;
+import reactor.core.publisher.Mono;
+
+import java.lang.reflect.Field;
+import java.util.Arrays;
+import java.util.List;
+
+public class ManagerPayloadResolver implements HandlerMethodArgumentResolver {
+    @Autowired
+    ManagerTokenVerifier managerTokenVerifier;
+
+    @Override
+    public boolean supportsParameter(MethodParameter methodParameter) {
+        boolean hasClassAnnotation = methodParameter.getDeclaringClass().isAnnotationPresent(AuthManagerController.class);
+        boolean hasMethodAnnotation = methodParameter.hasMethodAnnotation(AuthManagerResponse.class);
+        boolean hasParameterAnnotation = methodParameter.hasParameterAnnotation(ManagerPayload.class);
+        return (hasClassAnnotation || hasMethodAnnotation) && hasParameterAnnotation;
+    }
+
+    @Override
+    public Mono<Object> resolveArgument(MethodParameter methodParameter, BindingContext bindingContext, ServerWebExchange serverWebExchange) {
+        String accessToken = managerTokenVerifier.getTokenHeader(serverWebExchange);
+
+        ManagerPayload annotation = methodParameter.getParameterAnnotation(ManagerPayload.class);
+
+        String value = annotation.value(), pluck = annotation.pluck(), selectedField;
+
+        List<Field> declaredFields = Arrays.asList(Manager.class.getDeclaredFields());
+
+        Manager manager = managerTokenVerifier.createManagerFromToken(accessToken);
+
+        if (value.isEmpty() && pluck.isEmpty()) {
+            return Mono.just(manager);
+        } else {
+            selectedField = value.isEmpty() ? pluck : value;
+
+            if (!declaredFields.contains(selectedField))
+                return Mono.just(manager);
+
+            try {
+                Field field = Manager.class.getDeclaredField(selectedField);
+                field.setAccessible(true);
+
+                return Mono.just(field.get(manager));
+            } catch (Exception ignore) {
+                return Mono.just(manager);
+            }
+        }
+    }
+}
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