[aspectj-users] How to determine whether a nested class constructor is b

[Piers Powlesland <piers@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Hi

I am attempting to write an aspect that checks for null arguments  
passed to any constructors defined in our project, the problem i am  
having is that calls to constructors of inner classes get passed a  
*secret* parameter which evaluates to null. I cannot seem to figure  
out a way to determine whether the constructor called belongs to a  
nested class and therefore cannot avoid these special cases.

Here is some example code.

First the aspect that i have created

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package com.historicalengineering.wwii.aspect.test;

import java.lang.IllegalArgumentException;

public aspect EnforceContractAspect
{
	
	pointcut allMethodCallsWithParameters() :
		call(* com.historicalengineering..*(*,..));
	
	pointcut allConstructorCallsWithParameters() :
		call(com.historicalengineering..new(*,..)) ||
		call(private com.historicalengineering..new(*,..)) ||
		call(protected com.historicalengineering..new(*,..)) ||
		call(public com.historicalengineering..new(*,..));
	
	/*
	 * Select all calls to any methods or constructors defined within
	 * com.historicalengineering taking one or more parameters
	 */
	pointcut allCallsWithParameters() :
		allConstructorCallsWithParameters() ||
		allMethodCallsWithParameters();
		
		
	before() : allCallsWithParameters()
	{

		Object[] args = thisJoinPoint.getArgs();
		
		for(int i = 0; i < args.length; i++)
		{
			if(args[i] == null)
			{

				throw new IllegalArgumentException(
						thisJoinPointStaticPart.getSignature()
						+" passed null parameter at position "+(i+1)
						+" of "+args.length);
			}
		}
		
	}
}

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Second the test class

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package com.historicalengineering.wwii.aspect.test;

public class A
{

	public static void main(String[] args)
	{
		//A a = new A();
		//InnerStatic i = new InnerStatic();
		//a.foo();
		//a.bar();
		
	}
	
	protected void foo()
	{
		InnerStatic inner = new InnerStatic();
	}
	
	protected void bar()
	{
		Inner inner = new Inner();
	}
	
	static class InnerStatic
    	{	
       		private InnerStatic()
        	{
        	}
    	}
	
	class Inner
   	 {
        	private Inner()
       		{
        	}
    	}
	
}


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Third some output

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Output when uncommenting the line:	A a = new A();

-None because this constructor really doesn't take any parameters.



Output when uncommenting the line:	InnerStatic i = new InnerStatic();

Exception in thread "main" java.lang.IllegalArgumentException:  
com.historicalengineering.wwii.aspect.test.A.InnerStatic 
(A.InnerStatic) passed null parameter at position 1 of 1
	at  
com.historicalengineering.wwii.aspect.test.EnforceContractAspect.ajc 
$before 
$com_historicalengineering_wwii_aspect_test_EnforceContractAspect$1 
$f789a125(EnforceContractAspect.aj:45)
	at com.historicalengineering.wwii.aspect.test.A.main(A.java:9)

- As you can see from the trace the inner static constructor was  
passed an "A.InnerStatic"  type which has evaluated to null.



Output when uncommenting the lines:	A a = new A();  &	a.foo();

Exception in thread "main" java.lang.IllegalArgumentException:  
com.historicalengineering.wwii.aspect.test.A.InnerStatic 
(A.InnerStatic) passed null parameter at position 1 of 1
	at  
com.historicalengineering.wwii.aspect.test.EnforceContractAspect.ajc 
$before 
$com_historicalengineering_wwii_aspect_test_EnforceContractAspect$1 
$f789a125(EnforceContractAspect.aj:40)
	at com.historicalengineering.wwii.aspect.test.A.foo(A.java:17)
	at com.historicalengineering.wwii.aspect.test.A.main(A.java:10)

- Again the null "A.InnerStatic" type has been passed to the  
constructor.



Output when uncommenting the lines:	A a = new A();  &	a.bar();

Exception in thread "main" java.lang.IllegalArgumentException:  
com.historicalengineering.wwii.aspect.test.A.Inner(A, A.Inner) passed  
null parameter at position 2 of 2
	at  
com.historicalengineering.wwii.aspect.test.EnforceContractAspect.ajc 
$before 
$com_historicalengineering_wwii_aspect_test_EnforceContractAspect$1 
$f789a125(EnforceContractAspect.aj:40)
	at com.historicalengineering.wwii.aspect.test.A.bar(A.java:22)
	at com.historicalengineering.wwii.aspect.test.A.main(A.java:11)

-In the case of the non static nested class it is passed 2 hidden  
parameters the enclosing class "A" which does not evaluate to null  
and again the infuriating "A.Inner" class which is null.


Your thoughts and help would be very much appreciated.

Thank you

Piers