I am pretty certain I am right, inner classes initialize their pointer to the
outer field before calling their own super. EG:
| abstract class Base {
| Base() {
| System.out.println( getField() );
| }
|
| abstract int getField();
| }
|
The constructor calls the abstract method getField and if this abstract method
is implemented with an instance inner class then all is OK, e.g.:
| public class InnerTest {
| int field = 1;
|
| Base base() {
| return new Base() {
| int getField() {
| return field;
| }
| };
| }
|
| public static void main( final String[] notUsed ) {
| new InnerTest().base();
| }
| }
|
This prints 1 as you would expect. But if you hand code the inner class then it
won't work, e.g.:
| class Derived extends Base {
| final ExternalTest outer;
|
| Derived( final ExternalTest outer ) {
| this.outer = outer;
| }
|
| int getField() {
| return outer.field;
| }
| }
|
| public class ExternalTest {
| int field = 1;
|
| Base base() {
| return new Derived( this );
| }
|
| public static void main( final String[] notUsed ) {
| new ExternalTest().base();
| }
| }
|
This gives a NullPointerException since the field outer is not initialized when
constructor Derived calls its super constructor, Base. Also: you can see if
you dissassemble the code for InternalTest$1 that it initializes its pointer to
the outer class, this$0, before calling its super.
What the inner class does is equivalent to:
| Derived( final ExternalTest outer ) {
| this.outer = outer;
| super();
| }
| }
|
Which is illegal in Java because super is always called first.
My question is how can I do this in Javassist which also requires the call to
super to be the first line.
View the original post :
http://www.jboss.org/index.html?module=bb&op=viewtopic&p=3882299#3882299
Reply to the post :
http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&p=3882299
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