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[aspectj-users] Serialization aspect problem

Hi all

I'm trying to figure out what exactly is wrong with my pointcut/advice for a
serialisation aspect.

The code below is fairly simple but captures the problem I have.  Basically
I create an object of type Foo and set Foo.x to Foobar. My aspect has two
advice.. one for capturing instantiation of Foo and the other for capturing
setX on Foo objects.

On instantiation of Foo, I attempt to load a serialised file (Foo.ser).  If
it doesn't exist then an exception is thrown but the program carries on as
usual.  When I setX the second advice serializes the Foo object as file
Foo.ser.

Therefore when I run the program a second time I expect the Foo.ser file to
load and the contents loaded to the Foo object.  However, for some reason I
can't seem to show the loaded value in FooDriver only in the aspect.
Therefore, I am assuming my first advice is incorrectly written and the
loaded content is lost outside of the aspect.  I have tried a few different
varieties of around/after returning advice to no avail.

Can anyone spot the mistake in the first advice... it's driving me nuts!

Many thanks
Neil Loughran

  

import java.io.*;

class FooDriver  {
    public static void main(String args[])  {
        Foo f = new Foo();
        System.out.println("[FooDriver] x = "+f.getX()); // always null!!?

        f.setX("Foobar");
    }
}

class Foo  {
    public String x;
    public void setX(String _x)  {
        x = _x;
    }

    public String getX() {
		return x;
	}
}

aspect MyAspect  {
    declare parents: Foo implements Serializable;
    String filename = "Foo.ser";

    // problematic advice?
    after(Foo f): this(f) && execution (Foo.new())  {
        try  {
            f = (Foo) SerializeObject.load(filename);  
            System.out.println("[MyAspect] x = "+f.getX()); // works fine
here!
        }

        catch(Exception e)  {
            System.out.println("File not found "+ e);
        }
    }

    after(Foo f): this(f) && execution(public void Foo.setX(String))  {
        System.out.println("Setting");
        try  {
            SerializeObject.save(f,filename);
        }

        catch(IOException e)  {
            System.out.println("File not found "+ e);
        }
    }
}

class SerializeObject  {
    public static void save(Object obj, String filename) throws IOException
{
	  System.out.println("Saving file: "+filename);
        ObjectOutputStream objstream = new ObjectOutputStream(new
FileOutputStream(filename));
        objstream.writeObject(obj);
        objstream.close();
    }

    public static Object load(String filename) throws Exception  {
        System.out.println("Loading file: "+filename);
        ObjectInputStream objstream = new ObjectInputStream(new
FileInputStream(filename));
        Object obj = objstream.readObject();
        objstream.close();
        return obj;
    }
}



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