Can you get unexpected behavior if you set an aspect attribute without reloading the object after at

I've recently begun to use aspects in Documentum and from what I read it seamed that you always have to reload the object after you attach an aspect. Some sources:

In the Documentum Development Guide D65 I found this :


// Attach the aspect.
((IDfAspects)doc).attachAspect("customer_service_aspect",null);
// Save the document.
doc.save();
// Get the document with its newly attached aspect.
doc = (IDfDocument)mySession.getObject(doc.getObjectId());

Here I found this :

To work with the Aspect attached to my_obj you must re-fetch the object immediately after applying the Aspect.


((IDfAspects) my_obj).attachAspect(“my_aspect”,null);
 my_obj= (IDfDocument) session.getObject(my_obj.getObjectId());

And here at the bottom of the page:

If you are a regular client just use the sequence ..

(IDfAspects) obj).attachAspect(³foo², null);
IFoo = (IFoo) session.getObject(object.getObjectId());

The reason you have to do the getObject is that the aspect magic causes the actual Java object (obj) to become ³stale² in a special way (we don¹t have
time;-), and the object id, along with all its related state is reconstituted in a new Java object (which alone has the new interface).
getObject recovers a reference to this new Java object, you are happy, and the old one just fades away.

The thing is that I (accidentally) ran :


IDfDocument doc = (IDfDocument) mySession.getObject(new DfId("092e797d80097019"));
((IDfAspects) doc).attachAspect("dm_logical_version", null);
doc.setString("dm_logical_version.logical_version", "v0.1");
doc.save();

and it worked. No errors and the attribute saved in the repository. I'm interested only in saving some attributes (no behavior at the moment) and I'm wondering if you can get unexpected behavior if you set an aspect attribute without reloading the object after attaching the aspect?

Thanks in advance!

Bogdan

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Accepted answers

PanfilovAB

Your code is safe. Internally "client" code does not work directly with TBO classes, it works with TBO classes through BaseDoubleProxy that generates public (interface) methods using following way:

try {

((IDfSysobject)____referenceImp____ ()).save(params);

} finally {

____unreferenceImp____();

}

public synchronized Object ____referenceImp____()

{

this.m_activeCalls += 1;

return this.m_imp;

}

public void ____unreferenceImp____()

{

IProxyTarget notificationTarget = null;

synchronized (this)

{

if ((--this.m_activeCalls == 0) && (this.m_notify) && ((this.m_imp instanceof IProxyTarget))) {

notificationTarget = (IProxyTarget)this.m_imp;

}

if (notificationTarget != null) {

notificationTarget.onNoActiveCalls(); //this call rebuilds implementation

}

reloading object from cache in client code is required only to get access to methods introduced by aspect. Problem begins if you try to attach aspects inside TBO class to the current object, i.e. smth. like:

public void save() {

attachAspect();

super.save();

}

In that case you should implement IDfAttachAspectCallback to make implementation consistent.

All comments

PanfilovAB

Your aspect does not have implementation (i.e. it does not introduce new interfaces and methods), that's why your code works without getting rebuilt object from PersistentObjectManager (session.getObject()), compare to that:


/**
* @author Andrey B. Panfilov <andrew@panfilov.tel>
*/
public interface ISIInheritableAccessDocumentAspect {
}



/**
* @author Andrey B. Panfilov <andrew@panfilov.tel>
*/
public class InheritableAccessDocumentAspect extends DfDocument implements
        ISIInheritableAccessDocumentAspect {

    public InheritableAccessDocumentAspect() {
        super();
    }

    @Override
    protected synchronized void doSave(boolean keepLock, String versionLabels,
            Object[] extendedArgs) throws DfException {
        if (getFolderIdCountEx() > 0) {
            IDfFolder folder = (IDfFolder) getObjectSession().getObject(
                    getFolderIdEx(0));
            setACL(folder.getACL());
        }
        super.doSave(keepLock, versionLabels, extendedArgs);
    }

}


/**
* @author Andrey B. Panfilov <andrew@panfilov.tel>
*/
public class Test {

    public Test() {
        super();
    }

    public static void main(String[] argv) throws Exception {
        IDfSession session = new DfClient().newSession("ssc_dev",
                new DfLoginInfo("dmadmin", "dmadmin"));
        IDfSysObject object = (IDfSysObject) session.newObject("dm_document");
        object.save();
        ((IDfAspects) object).attachAspect(
                ISIInheritableAccessDocumentAspect.class.getSimpleName(), null);
        System.out
                .println("object instanceof ISIInheritableAccessDocumentAspect  = "
                        + (object instanceof ISIInheritableAccessDocumentAspect));
        System.out
                .println("((IPersistentObject) object).getProxyHandler()."
                        + "____getImp____() instanceof ISIInheritableAccessDocumentAspect = "
                        + (((IPersistentObject) object).getProxyHandler()
                                .____getImp____() instanceof ISIInheritableAccessDocumentAspect));
        object = (IDfSysObject) session.getObject(object.getObjectId());
        System.out
                .println("object instanceof ISIInheritableAccessDocumentAspect  = "
                        + (object instanceof ISIInheritableAccessDocumentAspect));
    }
}


object instanceof ISIInheritableAccessDocumentAspect  = false
((IPersistentObject) object).getProxyHandler().____getImp____() instanceof ISIInheritableAccessDocumentAspect = true
object instanceof ISIInheritableAccessDocumentAspect  = true

without getObject() call I'm unable to use interface introduced by aspect.

bog_sb

In my case, I don't need to use any new aspect methods. I just want to set the aspect's attributes and make sure the methods the aspect overrides are called (i.e. doSave(...)).

I implemented a test aspect called client_doc_aspect that has a few attributes and overrides doSave(). The aspect implementation :


public class ClientDocAspect extends DfDocument implements IClientDocAspect {
  @Override
  protected void doSave(boolean keepLock, String versionLabels, Object[] extendedArgs) throws DfException {
  String type = getString("client_doc_aspect.type");
  this.setString("client_doc_aspect.type", type + " client");
  this.setTime("client_doc_aspect.start_date", new DfTime(new Date()));
  super.doSave(keepLock, versionLabels, extendedArgs); 
  }
}

I ran :


IDfDocument doc = (IDfDocument) mySession.getObject(new DfId("092e797d80097937"));
((IDfAspects) doc).attachAspect("client_doc_aspect", null);
doc.setString("client_doc_aspect.type", "silver");
doc.setInt("client_doc_aspect.code",123);
doc.save();

and then I checked the attributes using dql and I saw that the overriden doSave() method was called(the start_date and type were set accordingly).

Performance is essential so I would like to skip having to rebuild the object after attaching aspects(if possible). I just want to be sure that no strange behavior can occur since in all articles I found about documentum aspects(which weren't that many) said that you should rebuild the object after attaching aspects.

Thanks!

PanfilovAB

Your code is safe. Internally "client" code does not work directly with TBO classes, it works with TBO classes through BaseDoubleProxy that generates public (interface) methods using following way:

try {

((IDfSysobject)____referenceImp____ ()).save(params);

} finally {

____unreferenceImp____();

}

public synchronized Object ____referenceImp____()

{

this.m_activeCalls += 1;

return this.m_imp;

}

public void ____unreferenceImp____()

{

IProxyTarget notificationTarget = null;

synchronized (this)

{

if ((--this.m_activeCalls == 0) && (this.m_notify) && ((this.m_imp instanceof IProxyTarget))) {

notificationTarget = (IProxyTarget)this.m_imp;

}

if (notificationTarget != null) {

notificationTarget.onNoActiveCalls(); //this call rebuilds implementation

}

public void save() {

attachAspect();

super.save();

}

In that case you should implement IDfAttachAspectCallback to make implementation consistent.