The problem is specifically with persisting objects in a many to one
relationship. The odd thing is that the my code was working fine, and
then suddenly it was only persisting the objects some of the time,
completely non-deterministic and the code hadn't changed. This has
made it really hard to debug (it only happens sometimes and there is
no exception, it just doesn't persist)
For context, the app is a route optimization solver, and there is a
user class called OmrUser, and there are Location and Driver classes
that map to an OmrUser (Location3 and Driver are the class names).
(Each User saves locations and drivers, and solves optimizations to
route them). Many locations roll up to one user, and right now
locations save only some of the time and it is getting worse.
The odd thing is the Driver class persists fine, and the code is the
same.
Snippet of OmrUser class (userlocs is the list collection where
Location3 objects are saved in the many to one mapping):
@PersistenceCapable(identityType = IdentityType.APPLICATION,
detachable = "true")
public class OmrUser {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
@Persistent
private User gaeuser;
@Persistent(mappedBy = "omruser")
@Element(dependent = "true")
@Order(extensions = @Extension(vendorName="datanucleus", key=
"list-ordering", value="key asc"))
private List<Location3> userlocs;
@Persistent(mappedBy = "omruser")
@Element(dependent = "true")
@Order(extensions = @Extension(vendorName="datanucleus", key=
"list-ordering", value="key asc"))
private List<Driver> userdrivers;
.....<rest cut>
******************************************************************************************************************************************************
Snippet from Location3 class
@PersistenceCapable(identityType = IdentityType.APPLICATION,
detachable = "true")
public class Location3 implements Comparable<Location3> {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
@Persistent
private User author;
@Persistent
private OmrUser omruser;
@Persistent
private String addressname;
.....<rest cut>
*****************************************************************************************************************************************************************
Servlet that saves a location to a User
public class SaveLoc extends HttpServlet {
private static final Logger log =
Logger.getLogger(SaveLoc.class.getName());
public void doGet(HttpServletRequest request, HttpServletResponse
response)
throws IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest req, HttpServletResponse
resp)
throws IOException {
UserService userService = UserServiceFactory.getUserService();
User user = userService.getCurrentUser();
Integer MaxSaveLocs =
Integer.parseInt(System.getProperty("opt.maxlocsave"));
String address = req.getParameter("addr");
String addressname = req.getParameter("addrname");
Double addresslat =
Double.parseDouble(req.getParameter("lat"));
Double addresslon =
Double.parseDouble(req.getParameter("lon"));
Double servicetime =
Double.parseDouble(req.getParameter("servicetime"));
String msg = "";
List<OmrUser> omruserquery;
OmrUser thisomruser = null;
Date date = new Date();
Integer numlocs;
Key omruserkey;
PersistenceManager pm = PMF.get().getPersistenceManager();
Location3 location = new Location3(user, address, addressname,
date, addresslat, addresslon, servicetime);
log.info("Attempting to Add Location - " +
location.getAddressname());
try {
String select_query = "select from " +
OmrUser.class.getName();
Query query = pm.newQuery(select_query);
query.setFilter("gaeuser == paramAuthor");
query.declareParameters("java.lang.String paramAuthor");
omruserquery = (List<OmrUser>)
pm.newQuery(query).execute(user);
if(omruserquery.iterator().hasNext()) {
thisomruser = omruserquery.iterator().next();
} else {
thisomruser = CreateNewUser(user);
pm.makePersistent(thisomruser);
}
} finally {
numlocs = thisomruser.getNumlocs();
omruserkey = thisomruser.getKey();
pm.close();
}
PersistenceManager pm2 =
PMF.get().getPersistenceManager();
if(numlocs<MaxSaveLocs){
addLocationToUser(pm2, omruserkey, location);
} else {
msg = "You have exceeded the maximum number of
locations you
can save, please delete a location first.";
log.info("FAIL - Exceed max num locs");
}
pm2.close();
if(msg == ""){
resp.sendRedirect("locations.jsp");
} else {
resp.sendRedirect("/err.jsp?msg=" + msg);
}
}
public void addLocationToUser(PersistenceManager pm2, Key UserKey,
Location3 location) {
pm2.currentTransaction().begin();
try {
OmrUser omruser = pm2.getObjectById(OmrUser.class,
UserKey);
omruser.getUserlocs().add(location);
pm2.currentTransaction().commit();
} finally {
if (pm2.currentTransaction().isActive()) {
pm2.currentTransaction().rollback();
}
}
}
public OmrUser CreateNewUser(User user) {
OmrUser newuser = new OmrUser(user, "Basic");
log.info("Created new user " + newuser.getGaeuser().getEmail());
return newuser;
}
}
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