android - GCM MultiCastResult Approach -

this approach use gcm more 1000 devices. right way? cannot try unless have more 1000 users feedback appreciated , importantly checking errors correctly? , updating database in right way?

public class messagingendpoint {     private static final logger log = logger.getlogger(messagingendpoint.class.getname());     /**      * api keys can obtained google cloud console      */     private static final string api_key = system.getproperty("gcm.api.key");     private list<registrationrecord> records;       private list<string> getregistrationid() {          records = ofy().load().type(registrationrecord.class).list();         list<string> records_id = new arraylist<string>();          (int = 0; < records.size(); i++) {             records_id.add(records.get(i).getregid());         }         return records_id;     }       private list<list<string>> regidinthousands(list<string> list, final int l) {          list<list<string>> parts = new arraylist<list<string>>();         final int n = list.size();         (int = 0; < n; += l) {             parts.add(new arraylist<string>(list.sublist(i, math.min(n, + l))));         }         return parts;     }       *      * @param message message send      */     public void sendmessage(@named("message") string message) throws ioexception {         if (message == null || message.trim().length() == 0) {             log.warning("not sending message because empty");             return;         }         // crop longer messages         if (message.length() > 1000) {             message = message.substring(0, 1000) + "[...]";         }         sender sender = new sender(api_key);         message msg = new message.builder().adddata("message", message).build();          list<list<string>> regidsparts = regidinthousands(getregistrationid(), 1000);          (int = 0; < regidsparts.size(); i++) {             multicastresult multicastresult = sender.send(msg, regidsparts.get(i), 5);              if (multicastresult.getcanonicalids() != 0) {                 list<result> results = multicastresult.getresults();                 (int j = 0; j < results.size(); j++) {                     if (results.get(j).getmessageid() != null) {                         log.info("message sent " + regidsparts.get(i).get(j));                         string canonicalregid = results.get(j).getcanonicalregistrationid();                         if (canonicalregid != null) {                             // if regid changed, have update datastore                             log.info("registration id changed " + regidsparts.get(i).get(j) + " updating " + canonicalregid);                             regidsparts.get(i).set(j, canonicalregid);                                  ofy().save().entity(records.get((i*1000)+j)).now();                         } else {                             string error = results.get(j).geterrorcodename();                             if (error.equals(constants.error_not_registered)) {                                 log.warning("registration id " + regidsparts.get(i).get(j) + " no longer registered gcm, removing datastore");                                 // if device no longer registered gcm, remove datastore                                      ofy().delete().entity(records.get((i*1000)+j)).now();                             } else {                                 log.warning("error when sending message : " + error);                             }                         }                     }                 }             }         }     } } 

your code looks good, thing can notice quite verbose , complicated. can take @ 1 option if considerate error handling:

public void sendmessagetomultipledevices(string key, string value, arraylist devices) {

sender sender = new sender(myapikey); message message = new message.builder().adddata(key, value).build();     try {         multicastresult result = sender.send(message, devices, 5);         mtlog.info(tag, "result " + result.tostring());           (int = 0; < result.gettotal(); i++) {             result r = result.getresults().get(i);              if (r.getmessageid() != null) {                 string canonicalregid = r.getcanonicalregistrationid();                 if (canonicalregid != null) {                     // devices.get(i) has more on registration id: update database                  }             } else {                 string error = r.geterrorcodename();                 if (error.equals(constants.error_not_registered)) {                     // application has been removed devices.get(i) - unregister database                 }             }         }     } catch (ioexception ex) {         mtlog.err(tag, "sending message failed", ex);     } }