can I call methods from java application that use google cloud datastore in GAE without rewrite the code of connection to Datastore

Question

I created java application (myLocalAPP) to connect and access google cloud datastore. So, I use Google cloud Datastore API. However, I'm now finding that I have to use myLocalAPP in a GAE app. (I export myLocalAPP to jar and add it to GAE /lib).

The problem is that GAE has different API to connect to Google datastore and the connection,insert and retrieve methods that I've created them in myLocalAPP aren't working when I call them from GAE application. I got exception such:

java.lang.Error:  compilation problems: 
The method beginTransaction(TransactionOptions) in the type DatastoreService is not applicable for the arguments (DatastoreV1.BeginTransactionRequest)
The method lookup(DatastoreV1.LookupRequest) is undefined for the type DatastoreService
Entity.Builder cannot be resolved to a type
Type mismatch: cannot convert from DatastoreV1.Entity to Entity

So, I go back to myLocalAPP and try to change the connection method. I change the datastore object from

Datastore datastore = DatastoreFactory.get().create(DatastoreHelper.getOptionsfromEnv()
          .dataset(datasetId).build());

to

Datastore datastore = (Datastore )DatastoreServiceFactory.getDatastoreService();

but casting does not work. I need to use DatastoreService object and I have to rewrite the other methods. I would like to know is there any way other than rewriting the code?? and if I rewrite the code using GAE datastore API, is myLocalAPP will work again locally?? (not on GAE).

Thanks,

Ed Davisson Ed Davisson · Accepted Answer · 2014-10-27T17:08:37

The client library for communicating with Google Cloud Datastore is not currently compatible with the API used by App Engine Datastore.

There's an open issue on the Google Cloud Datastore issue tracker to enhance the App Engine Java client library to work on top of Cloud Datastore (this would also enable the use of higher-level libraries like Objectify). You can subscribe to that issue to receive updates.

can I call methods from java application that use google cloud datastore in GAE without rewrite the code of connection to Datastore

1 Answers