Error while trying to download/export the files by using the DFC code

The IDfOperation classes have an added benefit of abstracting ACS/Network location, etc. By using the IDfOperation classes you should get the benefits of the platform services. It does require a bit more code but you can chain multiple objects in one operation for a transaction. Working with one object at a time, I admit even I take the quick and low code route most of the time BUT if I need distributin/acs, etc (client side DFC) I might take the IDfOperation route.

What version of DFC are you using?
What is the format of the object you are exporting?

Assuming the exception is thrown here:

IDfExportNode node = (IDfExportNode)eo.add(doc);

can you try by doing:
IDfSysObject doc = (IDfSysObject) _idfSession.getObject(new DfId(docBean.getObject_id()));

Instead? I generally use IDfSysObject and the javadocs "imply" it:

If that works, let me know. You will still also need:

1. (Perhaps, it may default to native format but not sure) node.setFormat(doc.getFormat().getName())
2. eo.execute
3. In case your file does not export, there is a node.getErrors() to parse to give you any errors that occured.

Do let me know if any of the above helps, if so I may file a bug on preventing IDfDocument (not saying this is the problem, just using my somewhat dated knowledge when I used to develop more for a living) :)

When you create an object, you can an object id. However that does not mean it is saved or available to another session. The most likely causes of your issue are:

One process or session creates an object and returns an ID to another process before saving it or the ID was returned BUT the save failed. In your code I see there is a bean that stores the objectId so you could be persisting an objectID that was never persisted to the Documentum content store. I would start looking in that direction.

Sure, this is an area where it would be troubleshooting your processes/code is needed. Without something specific to look at/narrow to, anything at this point would be a wild guess. If there are things that were validated there by other processes, I would look to enable audit events so you can see what other processes could be failing or deleting, etc. Are you able to reproduce any of this with any type of unit tests?

You don't by chance use 2 different repositories for say dev and test with same name/docbase id do you? I have seen problems where someone clones a dev docbase to a test docbase and then a situation I call "cross-pollination" could happen. One danger of using/cloning an environment to another is that is is easy to mix things up between the 2 distinct repositories. One process saves to Repo A1, the other is fetching (what woudl be a valid id returned from A1 but is not in A2. Again, this is just a wild guess with an uncommon scenario but I have seen it.

Sure makes sense but if you query an object by qualification or fetch an object by ID, it will exist unless it was not saved or deleted.

Sorry, sometimes it may be days before I get a chance to look here. It is more of a free time activity (which is few and far between).

Where does the docId come from? How is that obtained?

Are you able to reproduce this with any type of Unit testing? THis is pseudo code, not complete

String dql = select r_object_id, object_name, a_content_type, r_creation_date from {insert type name here} where department_name = 'xxxxxxx'

IDfCollection col = null;

try {

col = runQuery(sql) // need to setup IDfQuery in this method and return collection
while(col.next()) {
logger.debug("Found objectId: " + col.getString("r_object_id") +
" Name: " + col.getString(col.getString("object_name") + " Modified: " +
col.getString("r_modify_date"));

String docId = col.getString("r_object_id");

BeanModule _m = new BeanModule();
String status = "";
DocumentBean doc = new DocumentBean();
try {
doc.setObject_id(docId);
doc.setContentType(contentType);
status = exportDocument(doc,_m.get_tempFilepath());
if(!status.equalsIgnoreCase("Export operation successful.")){
doc.setObject_id("");
}
}catch(Exception e) {
doc.setObject_id("");
DfLogger.error(this,"-Exception while exporting the Object ID "+docId, null, e);
}finally{
status = null;
}

} // end loop

} catch (Exception e) {
col.close();
}

public static IDfCollection runQuery(IDfSession session, String dql) throws DfException {
    IDfQuery query = new DfQuery();
    query.setDQL(dql);
    return query.execute(session,
          ((dql.toLowerCase().trim().startsWith("select")) ? DfQuery.DF_READ_QUERY : DfQuery.DF_EXEC_QUERY));
}

The bean info for name, date, etc might give some correlateable data to figure out what is going on as well. If the object is not returned/does not exist, it one of:

1. Was not persisted (create object without save or failed save/exception)
2. No permissions for the user running the export (or browse only permission vs. read)
3. Object was deleted