Is this something that happens locally, or in production? I haven't tried the code, but my suspicions are:
1. Something is happened with the serialization of the object when it's being saved. Could this value be set elsewhere? 2. The generics are breaking serialization. This seems strange to me, though Can you post UserDetails? If you aren't keen to solve this, another workaround would be to simply write your own serialization and deserialization code via JSON or protobuf. -- Ikai Lan Developer Programs Engineer, Google App Engine Blogger: http://googleappengine.blogspot.com Reddit: http://www.reddit.com/r/appengine Twitter: http://twitter.com/app_engine On Mon, Feb 28, 2011 at 10:01 PM, GWTNewbie <[email protected]> wrote: > Hello: > I am using memcache to keep track of logged users in an app that I am > building. However when I do a GET on the memcache I get an exception: > > exception: java.lang.ClassCastException: java.util.ArrayList cannot be > cast to java.util.HashMap > > From the logs it appears that the exception is caused by the > statement: > HashMap<String, UserDetails> userMap = (HashMap<String, > UserDetails>) _cache > .get(user.getInstance()); > in the method logOn. > > Any ideas as to what the issue could be ? > --------------------------------- > Code snippet below: > > import com.samuuhanet.main.shared.UserDetails; > > public class LoggedUsers { > private static LoggedUsers _cacheInstance; > private static boolean _invalidationDone = false; > > private Cache _cache; > > public static final Logger _log = Logger.getLogger(LoggedUsers.class > .getName()); > > private LoggedUsers() { > try { > CacheFactory cacheFactory = > CacheManager.getInstance() > .getCacheFactory(); > > _cache = > cacheFactory.createCache(Collections.emptyMap()); > } catch (CacheException e) { > // Log stuff > _log.log(Level.WARNING, "Error in creating the > Cache"); > } > > } > > public static synchronized LoggedUsers getInstance() { > if (_cacheInstance == null) { > _cacheInstance = new LoggedUsers(); > } > return _cacheInstance; > } > > public void logOn(UserDetails user) { > > if (_cache == null) > return; > > HashMap<String, UserDetails> userMap = (HashMap<String, > UserDetails>) _cache > .get(user.getInstance()); > // Check if user already exists > if (userMap == null) { > userMap = new HashMap<String, UserDetails>(); > } > > userMap.put(user.getUserName(), user); > _cache.put(user.getInstanceID(), userMap); > } > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
