2 Replies Latest reply on Nov 3, 2009 4:14 PM by kabirkhan

Dependency on non-existant bean when trying to create

kabirkhan Nov 3, 2009 1:11 PM

What's wrong with this? Attempting to add the intermediate bean mentioned in http://www.jboss.org/index.html?module=bb&op=viewtopic&t=162791. I found that adding BeanMetaData as a property to a bean seems to cause an unresolved dependency:

public class ThrowawayTestCase extends MicrocontainerTest
{

 public ThrowawayTestCase(String name)
 {
 super(name);
 }


 public void testIndirectBean() throws Throwable
 {
 BeanMetaDataBuilder builder = BeanMetaDataBuilder.createBuilder("Bean", MyBean.class.getName());
 BeanMetaData bmd = builder.getBeanMetaData();

 builder = BeanMetaDataBuilder.createBuilder("BeanInstaller", MyBeanInstaller.class.getName());
// builder.addPropertyMetaData("context", builder.createFromContextInject(FromContext.CONTEXT)); //1
 builder.addPropertyMetaData("beanMetaData", builder.createValue(bmd)); //2
 KernelControllerContext ctx = deploy(builder.getBeanMetaData());
 try
 {
 System.out.println("----------> " + ctx.getDependencyInfo().getIDependOn(null));
 MyBeanInstaller myBeanInstaller = assertBean("BeanInstaller", MyBeanInstaller.class);

// MyBean myBean = assertBean("MyBean", MyBean.class);
// assertNotNull(myBean);
 }
 finally
 {
 undeploy(ctx);
 }
 }

 public static class MyBeanInstaller
 {
 KernelControllerContext context;

 BeanMetaData beanMetaData;

 boolean started;

 public BeanMetaData getBeanMetaData()
 {
 return beanMetaData;
 }

 public void setBeanMetaData(BeanMetaData beanMetaData)
 {
 this.beanMetaData = beanMetaData;
 }

 public KernelControllerContext getContext()
 {
 return context;
 }

 public void setContext(KernelControllerContext context)
 {
 this.context = context;
 }

 public boolean isStarted()
 {
 return started;
 }

 public void start() throws Exception
 {
 //Use context.getController() and beanmetadata to install indirect bean
 }
 }

 public static class MyBean
 {
 }
}

The output dependency info is shown as:

----------> [AbstractDependencyItem@5f49d886{name=BeanInstaller dependsOn=Bean whenRequired=Configured dependentState=Installed resolved=false}]

Looking at the stack trace of AbstractDependencyItem's constructor it looks like the property value gets visited as well?

Thread [main] (Suspended (breakpoint at line 78 in AbstractDependencyItem))
 AbstractDependencyItem.<init>(Object, Object, ControllerState, ControllerState) line: 78
 AbstractBeanMetaData.initialVisit(MetaDataVisitor) line: 669
 PreprocessMetaDataVisitor(AbstractMetaDataVisitor).internalInitialVisit(MetaDataVisitorNode) line: 111
 PreprocessMetaDataVisitor(AbstractMetaDataVisitor).initialVisit(MetaDataVisitorNode) line: 74
 AbstractValueMetaData.initialVisit(MetaDataVisitor) line: 116
 PreprocessMetaDataVisitor(AbstractMetaDataVisitor).internalInitialVisit(MetaDataVisitorNode) line: 111
 PreprocessMetaDataVisitor(AbstractMetaDataVisitor).initialVisit(MetaDataVisitorNode) line: 74
 AbstractPropertyMetaData(AbstractFeatureMetaData).initialVisit(MetaDataVisitor) line: 101
 AbstractPropertyMetaData.initialVisit(MetaDataVisitor) line: 287
 PreprocessMetaDataVisitor(AbstractMetaDataVisitor).internalInitialVisit(MetaDataVisitorNode) line: 111
 PreprocessMetaDataVisitor(AbstractMetaDataVisitor).initialVisit(MetaDataVisitorNode) line: 74
 AbstractBeanMetaData(AbstractFeatureMetaData).initialVisit(MetaDataVisitor) line: 101
 AbstractBeanMetaData.initialVisit(MetaDataVisitor) line: 680
 PreprocessMetaDataVisitor.run() line: 53
 AccessController.doPrivileged(PrivilegedAction<T>) line: not available [native method]
 AbstractKernelControllerContext.preprocessMetaData() line: 232
 AbstractKernelControllerContext.setController(Controller) line: 198
 AbstractKernelController(AbstractController).install(ControllerContext, boolean) line: 778
 AbstractKernelController(AbstractController).install(ControllerContext) line: 564
 AbstractKernelController.install(BeanMetaData, Object) line: 107
 AbstractKernelController.install(BeanMetaData) line: 101
 MicrocontainerTestDelegate.deploy(BeanMetaData) line: 329
 ThrowawayTestCase(MicrocontainerTest).deploy(BeanMetaData) line: 358
 ThrowawayTestCase.testIndirectBean() line: 54

I'm not sure this is something we should fix, without a better understanding of how the value metadata is visited. I can work around it by creating an intermediate class

 public static class BeanMetaDataWrapper
 {
 private final BeanMetaData beanMetaData;

 public BeanMetaDataWrapper(BeanMetaData beanMetaData)
 {
 this.beanMetaData = beanMetaData;
 }

 public BeanMetaData getBeanMetaData()
 {
 return beanMetaData;
 }
 }

and to set that instead when creating BeanInstaller

 builder.addPropertyMetaData("beanMetaDataWrapper", builder.createValue(wrapper));

1. Re: Dependency on non-existant bean when trying to create

alesj Nov 3, 2009 3:49 PM (in response to kabirkhan)
Yes, this is somehow expected.

PropertyMD --> ValueMD --> BeanMD --> inner bean --> dependency

AbstractValueMD::getChildren doesn't distinguish between plain properly value and metadata value.

Normally MC metadata should be hidden for POJOs,
so I wouldn't put too much effort into this --> would go with a wrapper.

Perhaps you can add this to BMDBuilder:
<T> T wrap(T impl, Class<T> clazz) { return new MetaDataWrapper<T>(impl, clazz); } public class MetaDataWrapper<T> { T impl; Class<T> clazz; public MetaDataWrapper(T impl, Class<T> clazz) { ... } public T unwrap() { return impl; } }

which hides the actual metadata in generic way.
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2. Re: Dependency on non-existant bean when trying to create

kabirkhan Nov 3, 2009 4:14 PM (in response to kabirkhan)
And users would have which setter in their bean?

This
void setMetaData(MetaDataWrapper<BeanMetaData> data){}

or this, which would require mc to be more clever?
void setMetaData(BeanMetaData data){}
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