Hi Bruno,
For the current project I'm working on we are using Spring AOP framework to intercept method calls on a number of prototypes. 90% of the time it's fine but during some load testing we noticed a number of exceptions being thrown by Spring:
Exception type: Spring.Objects.Factory.ObjectCreationException
Source: Spring.Core
Message: Error creating object with name '' : IFactoryObject threw exception on object creation.
Stack trace: at Spring.Objects.Factory.Support.AbstractObjectFacto ry.GetObjectForSharedInstance(String name, Object instance)
at Spring.Objects.Factory.Support.AbstractObjectFacto ry.GetObject(String name, Type requiredType, Object[] arguments)
at Spring.Objects.Factory.Support.AbstractObjectFacto ry.GetObject(String name, Object[] arguments)
at Spring.Objects.Factory.Support.AbstractObjectFacto ry.GetObject(String name)
at Spring.Context.Support.AbstractApplicationContext. GetObject(String name)
....
The inner exception details:
Exception type: System.NullReferenceException
Source: Spring.Aop
Message: Object reference not set to an instance of an object.
Stack trace: at Spring.Aop.Framework.DynamicProxy.CompositionProxy Builder.BuildProxy(IAdvised advised)
at Spring.Aop.Framework.DynamicProxy.DynamicProxyMana ger.GetProxy(AdvisedSupport advised)
at Spring.Aop.Framework.DefaultAopProxyFactory.Create AopProxy(AdvisedSupport advisedSupport)
at Spring.Aop.Framework.AdvisedSupport.CreateAopProxy ()
at Spring.Aop.Framework.ProxyFactoryObject.NewPrototy peInstance()
at Spring.Aop.Framework.ProxyFactoryObject.GetObject( )
at Spring.Objects.Factory.Support.AbstractObjectFacto ry.GetObjectForSharedInstance(String name, Object instance)
Exception type: System.NullReferenceException
Source: Spring.Aop
Message: Object reference not set to an instance of an object.
Stack trace: at Spring.Aop.Support.NameMatchMethodPointcut.Matches (MethodInfo method, Type targetType)
at Spring.Aop.Framework.AdvisorChainFactoryUtils.Calc ulateInterceptors(IAdvised config, Object proxy, MethodInfo method, Type targetType)
at Spring.Aop.Framework.HashtableCachingAdvisorChainF actory.GetInterceptors(IAdvised advised, Object proxy, String methodId, MethodInfo method, Type targetType)
at Spring.Aop.Framework.DynamicProxy.BaseCompositionP roxy.GetInterceptors(Type targetType, String methodId, MethodInfo method)
I extracted part of our application into a simple console application to test this scenario. Here is my config file:
<objects xmlns="http://www.springframework.net" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.net http://www.springframework.net/xsd/spring-objects.xsd">
<object id="AOPAdvice" type="Spring.Aop.Support.NameMatchMethodPointcutAdvisor" singleton="false">
<property name="MappedName" value="Execute"/>
<property name="Advice">
<object type="TestConsole.Spring.AOP.AOPAdvice, TestConsole">
</object>
</property>
</object>
<object id="ProxyObject" type="Spring.Aop.Framework.ProxyFactoryObject, Spring.Aop">
<property name="proxyInterfaces" value="TestConsole.Spring.ITask" />
<property name="isSingleton" value="false"/>
<property name="targetName" value="RealObjectPrototypeTarget" />
<property name="interceptorNames">
<list>
<value>AOPAdvice</value>
</list>
</property>
</object>
<object id="RealObjectPrototypeTarget" type="Spring.Aop.Target.PrototypeTargetSource, Spring.Aop" singleton="false">
<property name="TargetObjectName">
<idref object="RealObjectTarget"/>
</property>
</object>
<object id="RealObjectTarget" type="TestConsole.Spring.Tasks.TestTask, TestConsole" singleton="false"/>
</objects>
Here is the code for my main class:
class Program
{
static void Main(string[] args)
{
// Initialise Spring first
InitialiseSpring();
// Spawn 5 threads, each thread executing the TestProxyObject() method
List<Thread> testThreads = new List<Thread>();
for (int i = 0; i < 5; i++)
{
testThreads.Add(new Thread(TestProxyObject));
}
// Execute the threads
for (int i = 0; i < 5; i++)
{
testThreads[i].Start();
}
}
private static void TestProxyObject()
{
ITask task = ContextRegistry.GetContext("Test").GetObject("ProxyObject") as ITask;
task.Execute();
}
private static void InitialiseSpring()
{
ContextRegistry.Clear();
IApplicationContext context = new XmlApplicationContext("assembly://TestConsole/TestConsole/Spring.Spring.config.xml");
ContextRegistry.RegisterContext("Test", context);
}
}
I've got a number of Console.WriteLine() statements which output a local integer variable in the class:
>>> AOPInvoke (6)
>>> AOPInvoke (7)
>>> TestTask (7)
>>> TestTask (6)
TestTask (6) = 1
<<< TestTask (6)
AOPAdvice = (6) = 1
<<< AOPInvoke (6)
TestTask (7) = 1
<<< TestTask (7)
AOPAdvice = (7) = 1
<<< AOPInvoke (7)
The number in the brackets is the CurrentThread.ManagedThreadId. The application crashes soon after the exception above is displayed.
If from my main class I call TestProxyObject() explicitly (ie. not delegated to a thread):
static void Main(string[] args)
{
InitialiseSpring();
TestProxyObject();
TestProxyObject();
TestProxyObject();
TestProxyObject();
TestProxyObject();
TestProxyObject();
}
It works fine. Console output:
>>> AOPInvoke (1)
>>> TestTask (1)
TestTask (1) = 1
<<< TestTask (1)
AOPAdvice = (1) = 1
<<< AOPInvoke (1)
>>> AOPInvoke (1)
>>> TestTask (1)
TestTask (1) = 1
<<< TestTask (1)
AOPAdvice = (1) = 1
<<< AOPInvoke (1)
>>> AOPInvoke (1)
>>> TestTask (1)
TestTask (1) = 1
<<< TestTask (1)
AOPAdvice = (1) = 1
<<< AOPInvoke (1)
>>> AOPInvoke (1)
>>> TestTask (1)
TestTask (1) = 1
<<< TestTask (1)
AOPAdvice = (1) = 1
<<< AOPInvoke (1)
>>> AOPInvoke (1)
>>> TestTask (1)
TestTask (1) = 1
<<< TestTask (1)
AOPAdvice = (1) = 1
<<< AOPInvoke (1)
>>> AOPInvoke (1)
>>> TestTask (1)
TestTask (1) = 1
<<< TestTask (1)
AOPAdvice = (1) = 1
<<< AOPInvoke (1)
Any ideas? Is it a problem with my spring config xml or something more disturbing? :)