Improving field get and set performance with ASM or Javassist

Posted by ng on Stack Overflow See other posts from Stack Overflow or by ng
Published on 2010-06-11T12:37:03Z Indexed on 2010/06/12 9:42 UTC
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I would like to avoid reflection in an open source project I am developing. Here I have classes like the following.

public class PurchaseOrder {

   @Property
   private Customer customer;

   @Property
   private String name;
}

I scan for the @Property annotation to determine what I can set and get from the PurchaseOrder reflectively. There are many such classes all using java.lang.reflect.Field.get() and java.lang.reflect.Field.set().

Ideally I would like to generate for each property an invoker like the following.

public interface PropertyAccessor<S, V> {
   public void set(S source, V value);
   public V get(S source);
}

Now when I scan the class I can create a static inner class of PurchaseOrder like so.

static class customer_Field implements PropertyAccessor<PurchaseOrder, Customer> {
   public void set(PurchaseOrder order, Customer customer) {
      order.customer = customer;
   }  
   public Customer get(PurchaseOrder order) {
      return order.customer;
   }
}

With these I totally avoid the cost of reflection. I can now set and get from my instances with native performance. Can anyone tell me how I would do this. A code example would be great. I have searched the net for a good example but can find nothing like this. The ASM and Javasist examples are pretty poor also.

The key here is that I have an interface that I can pass around. So I can have various implementations, perhaps one with Java Reflection as a default, one with ASM, and one with Javassist?

Any help would be greatly appreciated.

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