Recently I am using mongodb java async driver which is newly released. I am writing some simple test codes, which are:
MongoClient mongoClient = MongoClients.create();
System.out.println("database has been connected!");
SingleResultCallback<Void> callbackWhenFinished = new SingleResultCallback<Void>() {
@Override
public void onResult(final Void result, final Throwable t) {
System.out.println("Operation Finished!");
}
};
mongoClient.listDatabaseNames().forEach(new Block<String>() {
@Override
public void apply(final String s) {
System.out.println(s);
}
}, callbackWhenFinished);
however, the callback function is not called, the console output is:
April 18, 2015 10:50:27 afternoon com.mongodb.diagnostics.logging.JULLogger log message: Cluster created with settings {hosts=[localhost:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
database has been connected! April 18, 2015 10:50:28 afternoon com.mongodb.diagnostics.logging.JULLogger log message: No server chosen by ReadPreferenceServerSelector{readPreference=primary} from cluster description ClusterDescription{type=UNKNOWN, connectionMode=SINGLE, all=[ServerDescription{address=localhost:27017, type=UNKNOWN, state=CONNECTING}]}. Waiting for 30000 ms before timing out
So you can see there is no callback function called. Anyone knows why?