We Keep Coding

How to audit methods in Java Spring Boot

I am writing a Spring Boot Application. I want to audit methods with my annotation #AuditMetod: For example I have method foo() with the annotation:
#AuditMetod(name = "SomeValue")
foo() {...}
I want to handle and audit such methods like this (the simplest example):
auditMethod(Method method) {
if (method.hasAnnotation(AuditMethod.class)) {
System.out.println (method.getName() + " was called at " + new Date())
}
}
upd
Thanks to #Karthikeyan #Swapnil Khante and #misha2048 I understood, that I need to use AOP. But I have 2 problems:
The only method in Aspect class in not being called and I don't see the inscription "----------ASPECT METHOD IS CALLED-----------" in log
How can I check in aspect method what method it is intercepting. To get an instance of Method class.
Now I have the following code:
Controller:
#PostMapping
#LoggingRest(executor = "USER", method = "CREATE", model = "SUBSCRIPTION")
public ResponseEntity<?> create(#Valid #RequestBody SubscriptionRequestDto dto) {
...
}
Aspect:
`#Aspect
#Slf4j
#Component
public class AuditAspect {
#Pointcut(value = "#annotation(com.aspect.annotations.LoggingRest)")
public void auditMethod(ProceedingJoinPoint proceedingJoinPoint) {
log.info("----------ASPECT METHOD IS CALLED------------");
}`
And annotation:
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.METHOD)
public #interface LoggingRest {
String executor() default "SYSTEM";
String method() default "";
String model() default "";
}

Auditing is a cross-cutting concern and can be handled using AOP.
Another solution would be to use a low-level solution by writing a custom annotation and using a Spring interceptorto write your business logic.
To use the Spring interceptor you will need to implement the HandlerInterceptor interface
Example of the annotation
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
public #interface Audit {
boolean active() default true;
}
Interceptor example
#Component
public class AuditInterceptor implements HandlerInterceptor {
#Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception {
if (handler instanceof HandlerMethod) {
HandlerMethod handlerMethod = (HandlerMethod) handler;
Audit annotation = handlerMethod.getMethodAnnotation(Audit.class);
if (annotation != null && annotation.active()) {
// your business logic
}
}
HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
}
check this interceptor example

I think one of the solutions here, as #Karthikeyan mentioned, is to use Spring AOP.
If you are not aware a brief introduction - spring-aop module implements the aspect oriented programming paradigm. We extract some common functionality, that we generally want to apply to some subset of functions/methods, to an entity called Aspect (see class annotated with #Aspect). This class will contain out cross-cutting functionality - such as auditing, for instance we want to audit the methods execution time, lets say. We just put the code to be executed, the condition, which tell the spring what exact beans methods should be affect by this aspect, see below.
For example, if I can audit the method execution duration with the following very simple example (in my case I said that any public method, returning void inside the Class com.example.stackoverflow.BusinessLogicClass must be inspected by this Aspect):
#SpringBootApplication
#EnableAspectJAutoProxy
public class StackoverflowApplication implements ApplicationRunner {
#Autowired
private BusinessLogicClass businessLogicClass;
public static void main(String[] args) {
SpringApplication.run(StackoverflowApplication.class, args);
}
#Override
public void run(ApplicationArguments args) throws Exception {
businessLogicClass.test();
}
}
#Aspect
#Component
class MyAspectLogicClass {
#Around("execution(public void com.example.stackoverflow.BusinessLogicClass.*(..))")
public Object hangAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
long before = System.currentTimeMillis();
Object returnedValue = proceedingJoinPoint.proceed();
long after = System.currentTimeMillis();
System.out.printf("Retruned in '%s' ms %n", (after - before));
return returnedValue;
}
}
#Component
class BusinessLogicClass {
public void test() {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
In my case, I will get the time before method execution, then by the means of
proceedingJoinPoint.proceed() call I delegate the execution to the real method, and then, once I get the response back, I will get the current system time and calculate the execution time, fairly simple.
I hope I have at least directed you somewhere, if you are looking for documentation, this are the resources I suggest you should look for:
https://docs.spring.io/spring-framework/docs/2.5.x/reference/aop.html offical spring doc (stale a bit, but there are some valuable things to learn)
https://docs.spring.io/spring-framework/docs/4.3.15.RELEASE/spring-framework-reference/html/aop.html is more fresh doc
Hope it helped :)

The problem was in right annotation. In Aspect class I tried #Around and everything works as I need.
#Aspect
#Slf4j
#Component
public class AuditAspect {
#Around(value = "#annotation(com.aspect.annotations.LoggingRest)")
public void auditMethod(ProceedingJoinPoint proceedingJoinPoint) {
var method = ((MethodSignature) proceedingJoinPoint.getSignature()).getMethod();
log.info("----------ASPECT METHOD IS CALLED------------");
}
}
For getting a Method instance I use fallowing code
Method method = ((MethodSignature) proceedingJoinPoint.getSignature()).getMethod();

Method invocation based on custom annotation in Spring?

I have a custom annotation:
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
public #interface Controller {
EventType[] events() default EventType.MESSAGE;
}
And there are methods in class B using them like below:
#Controller(events = {EventType.MESSAGE, EventType.DIRECT_MESSAGE})
public void onMessage(Message msg) { }
#Controller(events = {EventType.STAR_ADDED})
public void onStarAdded(Message msg) { }
Now, I want to invoke the above methods based on the annotation events value from another class A. In other words, when class A receives an event of type STAR_ADDED, I want to invoke all methods in class B with annotation #Controller(events = {EventType.STAR_ADDED}).
I know how to do this in Java but does Spring provide any API to do this? If yes, a code snippet would be helpful too.

Solution 1:
You could also do something like this:
enum EventType {
MESSAGE {
#Override
public void handleMessage(Service service, Message message) {
service.onMessage(message);
}
},
STAR_ADDED {
#Override
public void handleMessage(Service service, Message message) {
service.onStarAdded(message);
}
public abstract void handleMessage(Service service, Message message);
}
}
In your other class, where you know what is the "active" event:
yourEvent.handleMessage(service, message);
Solution 2:
I don't know if spring has anything precisely for that, otherwise you could also use reflection. Here's an example using reflection (I much prefer the solution above => enum without reflection):
for(Method method: Service.class.getDeclaredMethods()){
Controller annotation = m.getAnnotation(Controller.class);
for(EventType event: annotation.events()){
if(event.equals(yourActiveEventType)){
method.invoke(service, message);
}
return ...
}
}
Hint (not a solution) 3:
I really don't think the following applies for your scenario, but I thought I'd mention it... Spring AOP lets you trigger some code when an annotated method is called (it's kind of the opposite of your scenario), check this answer, but it may be worth the read for you: aspectj-pointcut-for-all-methods-of-a-class-with-specific-annotation
#Around("execution(#Controller * com.exemple.YourService.*(..))")
public Object aroundServiceMethodAdvice(final ProceedingJoinPoint pjp)
throws Throwable {
// perform actions before
return pjp.proceed();
// perform actions after
}
Solution 4: (added after comments)
Using org.reflections
<dependency>
<groupId>org.reflections</groupId>
<artifactId>reflections</artifactId>
<version>0.9.10</version>
</dependency>
example:
Service service = ...;
Message message = ...;
Set<Method> methods =
ReflectionUtils.getMethods(Service.class, ReflectionUtils.withAnnotation(Controller.class),ReflectionUtils.withParametersAssignableTo(Message.class));
for(Method m: methods){
Controller controller = m.getAnnotation(Controller.class);
for(EventType eventType: controller.value()){
if(EventType.MESSAGE.equals(eventType)){
m.invoke(service, message);
}
}
}
This assumes that you already hold the reference to the Service object (where your methods are).
Since you are using Spring, if your 'Services' are spring managed, you may get the instance from spring's context, you'll have to try it out for yourself, as this is somewhat bound to your design:
#Autowired
private ApplicationContext appContext;
Reflections r = new Reflections(new MethodAnnotationsScanner(), "com.your.package");
Set<Method> methods = r.getMethodsAnnotatedWith(Controller.class);
for(Method m: methods){
Controller controller = m.getAnnotation(Controller.class);
for(EventType eventType: controller.value()){
if(EventType.MESSAGE.equals(eventType)){
String className = m.getDeclaringClass().getSimpleName();
className = className.replaceFirst(className.substring(0,1), className.substring(0,1).toLowerCase());
Object service = appContext.getBean(className);
m.invoke(service, message);
}
}
}
This works if your Class is spring managed and is added to the context using its default camelcase name.
You may simplify the logic, but I believe the principal elements are there.

How to load Groovy object from text file by Spring?

I have:
Some interface:
public interface ISomeObject {
void someAction();
}
Some groovy file (someObject.groovy):
public class SomeObject implements ISomeObject {
#Autowired
SomeOtherClass someField;
#Override
void someAction(){};
}
I need to Spring automatically load autowired fields. How should I load this class?
Some code (for start) that load class without Spring:
GroovyClassLoader gcl = new GroovyClassLoader();
Class clazz = null;
try {
clazz = gcl.parseClass(new File("someObject.groovy"));
ISomeObject groovyObject = (ISomeObject ) clazz.newInstance();
return Optional.of(groovyObject);
} catch (IOException |InstantiationException|IllegalAccessException e) {
return Optional.empty();
}

Personally I would use a plain old factory in this case and wire all the properties "manually".
Although I made a small research and it looks like you have other options to do it. I believe this question is what you are looking for:
Registering beans(prototype) at runtime in Spring

JAX-RS: map method entity based on method annotation

I am using JAX-RS 2.0 with Jersey 2.6. I was wondering if it was possible to have something like this:
#GET
#Path("/get/{id}")
#MapTo(type = MyObjectDTO.class)
public MyObject getMyObject(#PathParam("id") String id){
MyObject o = ...
return o;
}
In the method above I am returning an instance of MyObject. However, I have defined the MapTo annotation to indicate that I want to map this object to MyObjectDTO. The way I was thinking this could work is to process the response early in a ContainerResponseFilter, detect the annotation MapTo and, assuming no error occurred, replace the entity in the response with an instance of MyObjectDTO created appropriately from the existing entity (of type MyObject).
However, I couldn't find a way to get the Method in the resource that was just called after the request came in, i.e., the getMyObject method, so that I can scan for the MapTo annotation.
Is there a way to achieve this in a JAX-RS-y kind of way?

Is this some serious reason you cannot return dto object? Sounds very strange...You can probably use AOP but I guess it would be bad practive
Here the Spring AOP example
http://docs.spring.io/spring/docs/2.5.4/reference/aop.html

I think I found a solution by reading this SO. I created a class that looks like this:
#Provider // or register in the configuration...
public class DTOMapperFeature implements DynamicFeature {
#Override
public void configure(ResourceInfo resourceInfo, FeatureContext context) {
for (Annotation annotation : resourceInfo.getResourceMethod().getAnnotations()) {
if (annotation instanceof MapTo) {
MapTo mapTo = (MapTo) annotation;
// Note: additional validation (return type shouldn't be void,
// collections are out etc.) is required before creating this,
// or should be pushed in the DTOMapperFilter.
// You get the gist: this filter will map the entity to an instance
// of the specified class (using a constructor in this case).
context.register(new DTOMapperFilter(
resourceInfo.getResourceMethod().getReturnType(),
mapTo.getResponseType());
}
}
}
#Priority(/* appropriate priority here! */)
public final static class DTOMapperFilter implements ContainerResponseFilter {
public DTOMapperFilter(Class<?> declaredReturnType, Class<?> responseType) {
// implementation omitted: find DTO constructor etc.
// throw if responseType does NOT have a constructor that takes an instance
// of declaredReturnType: catch errors at application bootstrap!
}
#Override
public void filter(
ContainerRequestContext requestContext,
ContainerResponseContext responseContext) throws IOException {
// implementation omitted: create instance of DTO class using constructor
}
}
}
Given sensible exceptions will be thrown from either the constructor of DTOMapperFilter or the configure method above, this should be pretty robust and errors detectable at test time.

How do Java method annotations work in conjunction with method overriding?

I have a parent class Parent and a child class Child, defined thus:
class Parent {
#MyAnnotation("hello")
void foo() {
// implementation irrelevant
}
}
class Child extends Parent {
#Override
foo() {
// implementation irrelevant
}
}
If I obtain a Method reference to Child::foo, will childFoo.getAnnotation(MyAnnotation.class) give me #MyAnnotation? Or will it be null?
I'm interested more generally in how or whether annotation works with Java inheritance.

Copied verbatim from http://www.eclipse.org/aspectj/doc/released/adk15notebook/annotations.html#annotation-inheritance:
Annotation Inheritance
It is important to understand the rules relating to inheritance of annotations, as these have a bearing on join point matching based on the presence or absence of annotations.
By default annotations are not inherited. Given the following program
#MyAnnotation
class Super {
#Oneway public void foo() {}
}
class Sub extends Super {
public void foo() {}
}
Then Sub does not have the MyAnnotation annotation, and Sub.foo() is not an #Oneway method, despite the fact that it overrides Super.foo() which is.
If an annotation type has the meta-annotation #Inherited then an annotation of that type on a class will cause the annotation to be inherited by sub-classes. So, in the example above, if the MyAnnotation type had the #Inherited attribute, then Sub would have the MyAnnotation annotation.
#Inherited annotations are not inherited when used to annotate anything other than a type. A type that implements one or more interfaces never inherits any annotations from the interfaces it implements.

You found your answer already: there is no provision for method-annotation inheritance in the JDK.
But climbing the super-class chain in search of annotated methods is also easy to implement:
/**
* Climbs the super-class chain to find the first method with the given signature which is
* annotated with the given annotation.
*
* #return A method of the requested signature, applicable to all instances of the given
* class, and annotated with the required annotation
* #throws NoSuchMethodException If no method was found that matches this description
*/
public Method getAnnotatedMethod(Class<? extends Annotation> annotation,
Class c, String methodName, Class... parameterTypes)
throws NoSuchMethodException {
Method method = c.getMethod(methodName, parameterTypes);
if (method.isAnnotationPresent(annotation)) {
return method;
}
return getAnnotatedMethod(annotation, c.getSuperclass(), methodName, parameterTypes);
}

Using Spring Core you can resolve with
AnnotationUtils.java

While the answer to the question as asked is that Java's Method.getAnnotation() does not consider overridden methods, sometimes it is useful to find these annotations. Here is a more complete version of Saintali's answer that I'm currently using:
public static <A extends Annotation> A getInheritedAnnotation(
Class<A> annotationClass, AnnotatedElement element)
{
A annotation = element.getAnnotation(annotationClass);
if (annotation == null && element instanceof Method)
annotation = getOverriddenAnnotation(annotationClass, (Method) element);
return annotation;
}
private static <A extends Annotation> A getOverriddenAnnotation(
Class<A> annotationClass, Method method)
{
final Class<?> methodClass = method.getDeclaringClass();
final String name = method.getName();
final Class<?>[] params = method.getParameterTypes();
// prioritize all superclasses over all interfaces
final Class<?> superclass = methodClass.getSuperclass();
if (superclass != null)
{
final A annotation =
getOverriddenAnnotationFrom(annotationClass, superclass, name, params);
if (annotation != null)
return annotation;
}
// depth-first search over interface hierarchy
for (final Class<?> intf : methodClass.getInterfaces())
{
final A annotation =
getOverriddenAnnotationFrom(annotationClass, intf, name, params);
if (annotation != null)
return annotation;
}
return null;
}
private static <A extends Annotation> A getOverriddenAnnotationFrom(
Class<A> annotationClass, Class<?> searchClass, String name, Class<?>[] params)
{
try
{
final Method method = searchClass.getMethod(name, params);
final A annotation = method.getAnnotation(annotationClass);
if (annotation != null)
return annotation;
return getOverriddenAnnotation(annotationClass, method);
}
catch (final NoSuchMethodException e)
{
return null;
}
}