CODEWITHSUNDEEP
javareflectionguavaaspectjaop
Abhiroop Sarkar
Abhiroop Sarkar

Reputation: 2311

Infering the type of the arguments in method for aspectj

In AOP(using Aspectj) to intercept a method call and acess its parameters we can use

Object[] args=joinPoint.getArgs();

But does the JoinPoint class gives us any feature to infer the type of the parameters? For instance:

public void setApples(List<Apple>){..}

All I get is an Object instance. Is there some way to infer the type of that parameter using the joinpoint properties or reflection or Guava TypeToken?

Upvotes: 1

Views: 1011

Answers (1)

Frank Pavageau
Frank Pavageau

Reputation: 11735

If the argument is not null, you can check the type using instanceof as @Babur writes in his comment, or inspect its Class when it's not null:

Object[] args = joinPoints.getArgs();
if (args[0] instanceof String) {
    System.out.println("First arg is a String of length " + ((String) args[0]).length());
}
if (args[1] == null) {
    System.out.println("Second arg is null");
} else {
    System.out.println("Second arg is a " + args[1].getClass());
}

If you really need to analyze the parameters of the method, you can cast jointPoint.getSignature() to a MethodSignature to access the Method:

if (joinPoint.getSignature() instanceof MethodSignature) {
    Method method = ((MethodSignature) jointPoint.getSignature()).getMethod();
    System.out.println("Method parameters: " + Arrays.toString(method.getParameterTypes()));
}

Upvotes: 1

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