datadb/compbio/cassandra/readers/CassandraReader.java

   1 package compbio.cassandra.readers;
   2
   3 import org.apache.log4j.Logger;
   4
   5 import com.datastax.driver.core.ResultSet;
   6 import com.datastax.driver.core.Session;
   7 import com.datastax.driver.core.exceptions.QueryExecutionException;
   8 import com.datastax.driver.core.exceptions.QueryValidationException;
   9 import compbio.cassandra.CassandraNativeConnector;
  10
  11 public class CassandraReader {
  12         private static long earlestDate = 0;
  13         private Session session;
  14         protected static Logger log = Logger.getLogger(CassandraNativeConnector.class);
  15
  16         public CassandraReader() {
  17                 Session inis = CassandraNativeConnector.getSession();
  18                 setSession(inis);
  19         }
  20
  21         public void setSession(Session s) {
  22                 assert s != null;
  23                 session = s;
  24         }
  25
  26         protected ResultSet CassandraQuery(String command) {
  27                 try {
  28                         ResultSet results = session.execute(command);
  29                         return results;
  30                 } catch (QueryExecutionException e) {
  31                         String mess = "CassandraUserManagerImpl.findAllUsers: query execution exception...";
  32                         System.out.println(mess);
  33                         log.error(mess);
  34                         log.error(e.getLocalizedMessage(), e.getCause());
  35                         return null;
  36                 } catch (QueryValidationException e) {
  37                         String mess = "CassandraUserManagerImpl.findAllUsers: query validation exception... Command: " + command;
  38                         System.out.println(mess);
  39                         log.error(mess);
  40                         log.error(e.getLocalizedMessage(), e.getCause());
  41                         return null;
  42                 }
  43
  44         }
  45
  46         /*
  47          * find the earliest date in the database
  48          */
  49         public static long earliestDate() {
  50                 earlestDate = CassandraNativeConnector.getEarliestDateInDB();
  51                 return earlestDate;
  52         }
  53
  54
  55 }