Comment 4 for bug 521471

I have partially fixed the bug. The program runs with some exceptions. The annotations are arranged according to their target span. If you add new annotations, you have to reopen the project to see the correct ranking of the annotations. However, due to the database design, we could create several annotations whose doc_id and link_doc_id are the same, which means that the relations between documents and annotations are "one-to-many". This relation leads to certain incorrect ranking of the annotations whose doc_id and link_doc_id are the same. Is this what we want? If we want to implement annotation for annotation, then we should have a "one-to-one" relation between documents and annotations, right?

In addition, when the user clicks one annotation to open it, the program will generate a java.lang.IllegalStateException: Attempt to mutate in notification, which does not affect the functionality of the program.

I have put all the relevant comments about the target span ordering implementation into "TODO" comments in the source code, which could be reviewed from selecting the menu item "Tasks" in Netbeans.