CODEWITHSUNDEEP
javaaspectjjavassist
Freewind
Freewind

Reputation: 198198

Can AspectJ replace field invocation to getter/setters?

For example, I have a class with a public field and corresponding getter/setters:

public class User {
    public String name;
    public String getName() { return name; }
    public void setName(String name) { this.name = name;}
}

Now invoke the field name:

User user = new User();
user.name = "test";
System.out.println(user.name);

Is it able to use aspectj to enhance the class to let the bytecode be:

User user = new User();
user.setName("test");
System.out.println(user.getName());

I know javassist can do this, but can AspectJ do the same?

Upvotes: 1

Views: 2840

Answers (2)

thk
thk

Reputation: 91

User user = new User();
user.setName("Bob");  //<- This line matched the pointcut below
user.name = "Alex";  //<- This line too matched the pointcut below
System.out.println("User name is " + user.name);

For the above code in the main method of User class, I wrote the below Aspect

public aspect UserAspect {
public pointcut propSet() : set(* User.*);

   void around() : propSet(){
    System.out.println(thisJoinPoint.getSignature() + " is being set");
    proceed();
   }
}

And the output was..

String test.User.name is being set
String test.User.name is being set
User name is Bob

So, my understanding is that AspectJ treats member variable assignment and a setter the same way. So, it might not be possible what you were able to do with Javassist

Upvotes: 2

Dave Newton
Dave Newton

Reputation: 160181

Check out the pointcut docs and theget(FieldPattern) and set(FieldPattern) pointcuts.

There is some additional writeup in the same doc.

Upvotes: 2

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