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Create Pointcut for Spring AOP annotation to put annotation on class and execute advice on every method in class

I want to have annotation on class level that will execute advice on every method in annotated class.
Is that even possible.
Example: I would like to annotate OmniDemoService with #DoSomethingForMe and I want both method1 and method2 to log "look at me" before execution
This example is not working and I don't know why. When I transform Pointcut to Around and just use it with annotation (also change annotation ElementType to method) everything is working on method level.
So I think it is wrong defined Pointcut.
Annotation:
#Target(ElementType.TYPE)
#Retention(RetentionPolicy.RUNTIME)
public #interface DoSomethingForMe {
}
Advice:
#Aspect
#Component
public class DoSomethingForMeAdvice {
private static final Logger logger = LoggerFactory.getLogger(DoSomethingForMeAdvice.class);
#Pointcut("execution(public * *(..)) && #annotation(DoSomethingForMe)")
public void anyAnnotatedMethod() {
}
#Before("anyAnnotatedMethod()")
public void acquireExecution() {
logger.info("look at me");
}
}
Usage:
#Service
#DoSomethingForMe
public class OmniDemoService {
private static final Logger logger = LoggerFactory.getLogger(OmniDemoService.class);
public void method1() {
logger.info("---1---");
}
public void method2() {
logger.info("---2---");
}
}

Your issue is that you are confusing pointcut definition with advices.
Pointcut is aiming, advice performs the actual WhateverYouWantToBeExecuted. Like for example
#Pointcut("#annotation(com.omnidemo.advice.DoSomethingForMe)")
public void anyAnnotatedMethod() {
}
#Before("anyAnnotatedMethod()")
public void logMethodCall(JoinPoint jp) {
String methodName = jp.getSignature().toShortString();
logger.info("Executing: " + methodName);
}

Solution for the problem is to use within for pointcut
#Pointcut("#within(DoSomethingForMe)")
public void anyAnnotatedMethod() {
}
#Before("anyAnnotatedMethod()")
public void acquireExecution() {
logger.info("look at me");
}
Solution provided by #J Asgarov in the comments

Check out what the AspectJ quick reference says about #annotation():
any join point where the subject has an annotation of type
SomeAnnotation
You used #annotation(DoSomethingForMe) but the "subject" of a method execution is a method. So that would mean any method annotated #DoSomethingForMe.
Use #this(DoSomethingForMe) or #target(DoSomethingForMe).
Thanks to kriegaex for pointing out that #this and #target must be evaluated at runtime, which would pollute the codebase a lot (i.e. check in every method). So the next approach is better:
If you check the AspectJ manual section about type patterns you will see that you can annotate the type directly. Please also remember to use use fully qualified class names. So that would be:
execution(public * (#com.path.DoSomethingForMe *).*(..))
Also, if you have such a simple pointcut and you don't need to reuse it, I think you can drop the additional method and just use it in the advice directly:
#Before("execution(public * (#com.path.DoSomethingForMe *).*(..))")
which says: "before the execution of any public method of a type annotated with #com.path.DoSomethingForMe", where "before the execution of a method" means "inside the method, at the beginning".
Alternatively, if this pointcut looks a bit too complicated for you, you can separate annotation matching and method matching like this, as suggested by J Asgarov in his comment:
#Before("execution(public * *(..)) && #within(com.path.DoSomethingForMe)")

Enforce subclass to add #Schedule to a method in super abstract class in Java Spring

I have a super abstract class that has some common implemented methods and other abstract methods to be implemented by a subclass. One of the common implemented methods is a method to be annotated as #Scheduled, but I want the subclass to define how this schedule should be defined (fixed delay, fixed rate or cron .. etc). How to implement such behaviour ?
One approach I thought of is to override the method to be scheduled in the subclass such that it just call its corresponding method in the super class and add the #Scheduled on it with the desired definition, but I don't know how to enforce the subclass to do so as this method is not abstract.
Super Abstract Class
public abstract class SuperClass {
public abstract void x();
public void y() {
// Some implementation
}
// Method to be scheduled.
public void scheduledMethod() {
x();
y();
}
}
Subclass
public class Subclass extends SuperClass {
#Override
public void x() {
// Some implementation
}
// How to enforce the developer to add this ?
#Scheduled(cron = "0 0 0 * * ?")
public void scheduledMethod(){
super.scheduledMethod();
}
}

I couldn't get my head around how you could use #Scheduled but, I've an alternative:
In your abstract class, require a method to be implemented by subclasses to return the schedule:
public String getCronString();
Programmatically schedule the task using Scheduler using the method getCronString() that's implemented in your subclasses, to return the cron schedule. Few examples on how to programmatically schedule tasks with Spring boot:
https://www.baeldung.com/spring-task-scheduler
SO Question
Basically, if your subclasses are not implementing public String getCronString(); your code won't compile.

One option would be to check that the #Scheduled annotation is present (or meta-present) at bean creation time. This can be easily achieved using reflection in a #PostConstruct method on the superclass:
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.util.ClassUtils;
public abstract class SuperClass {
...
#PostConstruct
public void enforceScheduling() {
boolean annotationPresent = AnnotationUtils.getAnnotation(ClassUtils.getMethod(getClass(), "scheduledMethod"), Scheduled.class) != null;
if (!annotationPresent) {
throw new IllegalStateException("#Scheduled annotation missing from scheduledMethod");
}
}
}
This will cause an exception to be thrown at application start-up time when Spring attempts to create the bean, failing fast and making it very obvious what is missing.

One thing I've done in the past in projects with constraints on a class hierarchy that I could not easily check at compile or runtime was to write a unit test that iterated through every concrete (non-abstract) instance of the class and checked whether it met that constraint.
Since this is using Spring, we probably care more that each bean of this type matches the constraint than whether each subclass on the classpath does.
The constraint in this case is that the #Scheduled annotation is present (or meta-present) on the given method in the subclass. The presence of the annotation can be easily achieved using reflection given the Class object of the subclass.
Putting this together, we can write a unit test utilizing this technique:
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.util.ClassUtils;
#SpringBootTest
public class SuperClassTest {
#Autowired
private List<SuperClass> beansOfThisType;
#Test
public void allBeansMustBeScheduled() {
for (SuperClass bean : beansOfThisType) {
boolean annotationPresent = AnnotationUtils.getAnnotation(ClassUtils.getMethod(bean.getClass(), "scheduledMethod"), Scheduled.class) != null;
assertTrue(annotationPresent, "#Scheduled annotation missing from scheduledMethod for " + bean.getClass());
}
}
}
Checking every object of the type on the classpath rather than just the Spring beans would be a very similar approach; the difference would be the mechanism to get the list of Class objects to check. Getting the matching objects from the classpath is non-straightforward enough that it's outside the scope of this answer. How do you find all subclasses of a given class in Java? lists a number of ways to accomplish it.

Spring-AOP pointcut not working?

Below is my code snippet:
ServiceImpl.java
#Service
public class ServiceImpl implements Service {
private Response worker(Audit send) throws ArgumentException {
System.out.println("STEP_1");
worker(send.getRequest(), send.getId());
}
private Response worker(Request request, String id) throws ArgumentException {
System.out.println("STEP_2");
try {
//throwing some exception
} catch (Exception e) {
System.out.println("STEP_3");
}
}
}
Now, what I want is whenever NullPointerException is being thrown from method worker(Request request, String id) as shown above I want to perform some specific task. For that I have written an Aspect class which is following:
MyAspect.java
#Aspect
#Component
public class MyAspect{
#Pointcut("com.xyz.myapp.ServiceImpl.worker() && args(request,..)")
private void someOperation(Request request) {}
#Before("someOperation(request)")
public void process(Request request) {
System.out.println("SUCCESS");
}
#AfterThrowing("com.xyz.myapp.ServiceImpl.worker() && args(request,..)")
public void doRecoveryActions() {
System.out.println("EXCEPTION_SUCCESS");
}
}
Current Output:
STEP_1
STEP_2
STEP_3
Desired Output:
STEP_1
STEP_2
STEP_3
SUCCESS
EXCEPTION_SUCCESS
As you can see MyAspect.java is not getting triggered hence NOT printing values.
What can be the reason for this?
Note:
I tried making worker as public classes too but it didn't work.
Also tried changing the name of the methods to eliminate any overloading issue that too didn't work.
Tried various other pointcut expressions all in vain as of now.
In my application there are other aspect classes working absolutely fine.

You made a typical Spring AOP beginner's mistake: You assume that it works for private methods, but as the documentation clearly says, it does not. Spring AOP is based on dynamic proxies, and those only work for public methods when implementing interfaces via JDK proxies and additionally for protected and package-scoped methods when using CGLIB proxies.
You should make the worker() method public if you want to intercept it from an aspect.
P.S.: Full-fledged AspectJ also works for private methods, but to switch to another AOP framework would be overkill here.
Update: You also have other problems in your code:
The first worker method, even if you make it public, does not return anything. The last statement should be return worker(send.getRequest(), send.getId());, not just worker(send.getRequest(), send.getId());.
Your pointcut com.xyz.myapp.ServiceImpl.worker() will never match because it has an empty argument list, but your method has arguments. The args() does not help you here.
The syntax of your pointcut is also wrong because it does not specify a return type for the method, not even *. Furthermore, the method name itself is not enough, it should be enclosed in an actual pointcut type such as execution(). I.e. you want to write something like:
#Pointcut("execution(* com.xyz.myapp.ServiceImpl.worker(..)) && args(request, ..)")
private void someOperation(Request request) {}

To intercept a method that throws an exception you can use this code (works only if methods are public):
#AfterThrowing(pointcut="com.xyz.myapp.SystemArchitecture.dataAccessOperation()",throwing="ex")
public void doRecoveryActions(NullPointerException ex) {
// ...
}
Source: Spring AOP

Where is the right place for annotation processing?

I write simple application. I don't want to use any frameworks. Please suggest me right place to hold annotation processing.
I have a few lines in main method:
String myString = (#NonNull String)list;
And I created #interface:
#Target({ElementType.TYPE_USE, ElementType.TYPE_PARAMETER})
public #interface NonNull {
}
Which step should I take next? Can I work with annotations without using reflection? Could you expose for me samples of such annotation processing code?

There is no way (AFAIK) to work with annotations without reflection.
If you don't want to use any framework, first step is to write kind of proxy class handling the method requests. It is an example of method processing with annotation use over method:
public class MyProxy {
private <T> T getProxy(T t) {
return (T) Proxy.newProxyInstance(t.getClass().getClassLoader(), new Class<?>[]{MyClass.class}, new MyInvocationHandler(t));
}
}
And then implement InvocationHandler:
public class MyInvocationHandler implements InvocationHandler {
private Object obj;
MyInvocationHandler (Object obj) {
this.obj = obj;
}
#Override
public Object invoke(Object proxy, final Method method, final Object[] args) throws Throwable {
boolean isNotNull = method.isAnnotationPresent(NotNull.class);
if (isNotNull) {
/* process annotated method. Or go through proxy object fields etc.. */
}
}
}
I hope it will help you.

You didn't say what kind of annotation processing you want to do.
Do you want to add a run-time check that will cause your code to crash if list is ever null at run time? For this, reflection will work.
Do you want to add a compile-time check that will reject your code if it cannot prove that list is never null at run time? For this, an annotation processor such as the Checker Framework will work.
Your question does not explain why you don't want to use a framework. Doing so will save you from re-implementing a lot of functionality that others have already created.

Code injection via custom annotation

Here's my use case:
I need to do some generic operation before and after each method of a given class, which is based on the parameter(s) of the method. For example:
void process(Processable object) {
LOGGER.log(object.getDesc());
object.process();
}
class BaseClass {
String method1(Object o){ //o may or may not be Processable(add process logic only in former case)
if(o intstanceof Prcessable){
LOGGER.log(object.getDesc());
object.process();
}
//method logic
}
}
My BaseClass has a lot of methods and I know for a fact that the same functionality will be added to several similar classes as well in future.
Is something like the following possible?
#MarkForProcessing
String method1(#Process Object o){
//method logic
}
PS: Can AspectJ/guice be used? Also want to know how to implement this from scratch for understanding.
Edit: Forgot to mention, what I have tried.(Not complete or working)
public #interface MarkForProcessing {
String getMetadata();
}
final public class Handler {
public boolean process(Object instance) throws Exception {
Class<?> clazz = instance.getClass();
for(Method m : clazz.getDeclaredMethods()) {
if(m.isAnnotationPresent(LocalSource.class)) {
LocalSource annotation = m.getAnnotation(MarkForProcessing.class);
Class<?> returnType = m.getReturnType();
Class<?>[] inputParamTypes = m.getParameterTypes();
Class<?> inputType = null;
// We are interested in just 1st param
if(inputParamTypes.length != 0) {
inputType = inputParamTypes[0];
}
// But all i have access to here is just the types, I need access to the method param.
}
return false;
}
return false;
}

Yes, it can be done. Yes, you can use AspectJ. No, Guice would only be tangentially related to this problem.
The traditional aspect approach creates a proxy which is basically a subclass of the class you've given it (e.g. a subclass of BaseClass) but that subclass is created at runtime. The subclass delegates to the wrapped class for all methods. However, when creating this new subclass you can specify some extra behavior to add before or after (or both) the call to the wrapped class. In other words, if you have:
public class Foo() {
public void doFoo() {...}
}
Then the dynamic proxy would be a subclass of Foo created at runtime that looks something like:
public class Foo$Proxy {
public void doFoo() {
//Custom pre-invocation code
super.doFoo();
//Custom post-invocation code
}
}
Actually creating a dynamic proxy is a magical process known as bytecode manipulation. If you want to to do that yourself you can use tools such as cglib or asm. Or you can use JDK dynamic proxies. The main downside to JDK proxies are that they can only wrap interfaces.
AOP tools like AspectJ provide an abstraction on top of the raw bytecode manipulation for doing the above (you can do a lot with bytecode manipulation, adding behavior before and after methods is all aspects allow). Typically they define 'Aspect's which are classes that have special methods called 'advice' along with a 'pointcut' which defines when to apply that advice. In other words you may have:
#Aspect
public class FooAspect {
#Around("#annotation(MarkForProcessing)")
public void doProcessing(final ProceedingJoinPoint joinPoint) throws Throwable
{
//Do some before processing
joinPoint.proceed(); //Invokes the underlying method
//Do some after processing
}
}
The aspect is FooAspect, the advice is doProcessing, and the pointcut is "#annotation(MarkForProcessing)" which matches all methods that are annotated with #MarkForProcessing. It's worth pointing out that the ProceedingJoinPoint will have a reference to the actual parameter values (unlike the java.lang.reflect.Method)
The last step is actually applying your aspect to an instance of your class. Typically this is either done with a container (e.g. Guice or Spring). Most containers have some way of knowing about a collection of aspects and when to apply them to classes constructed by that container. You can also do this programmatically. For example, with AspectJ you would do:
AspectJProxyFactory factory = new AspectJProxyFactory(baseClassInstance);
factory.addAspect(FooAspect.class);
BaseClass proxy = factory.getProxy();
Last, but not least, there are AOP implementations which use compile-time "weaving" which is a second compilation step run on the class files that applies the aspects. In other words, you don't have to do the above or use a container, the aspect will be injected into the class file itself.