Package org.aopalliance.intercept

Interface FieldInterceptor

All Superinterfaces:

Advice, Interceptor

public interface FieldInterceptor
extends Interceptor

Intercepts field access on a target object.

The user should implement the set(FieldAccess) and get(FieldAccess) methods to modify the original behavior. E.g. the following class implements a tracing interceptor (traces the accesses to the intercepted field(s)):

 class TracingInterceptor implements FieldInterceptor {

   Object set(FieldAccess fa) throws Throwable {
     System.out.println("field "+fa.getField()+" is set with value "+
                        fa.getValueToSet());
     Object ret=fa.proceed();
     System.out.println("field "+fa.getField()+" was set to value "+ret);
     return ret;
   }

   Object get(FieldAccess fa) throws Throwable {
     System.out.println("field "+fa.getField()+" is about to be read");
     Object ret=fa.proceed();
     System.out.println("field "+fa.getField()+" was read; value is "+ret);
     return ret;
   }
 }
 

Method Summary

Modifier and Type	Method	Description
java.lang.Object	get(FieldAccess fieldRead)	Do the stuff you want to do before and after the field is getted.
java.lang.Object	set(FieldAccess fieldWrite)	Do the stuff you want to do before and after the field is setted.

Method Detail

get

java.lang.Object get(FieldAccess fieldRead)
              throws java.lang.Throwable

Do the stuff you want to do before and after the field is getted.

Polite implementations would certainly like to call Joinpoint.proceed().

Parameters:

fieldRead - the joinpoint that corresponds to the field read

Returns:

the result of the field read Joinpoint.proceed(), might be intercepted by the interceptor.

Throws:

java.lang.Throwable - if the interceptors or the target-object throws an exception.

set

java.lang.Object set(FieldAccess fieldWrite)
              throws java.lang.Throwable

Do the stuff you want to do before and after the field is setted.

Polite implementations would certainly like to implement Joinpoint.proceed().

Parameters:

fieldWrite - the joinpoint that corresponds to the field write

Returns:

the result of the field set Joinpoint.proceed(), might be intercepted by the interceptor.

Throws:

java.lang.Throwable - if the interceptors or the target-object throws an exception.