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
  10 import compbio.cassandra.CassandraNativeConnector;
  11
  12 public class CassandraReader {
  13         protected static long earlestDate = 0;
  14         protected Session session;
  15         protected static Logger log = Logger.getLogger(CassandraNativeConnector.class);
  16
  17         public CassandraReader() {
  18                 Session inis = CassandraNativeConnector.getSession();
  19                 setSession(inis);
  20         }
  21
  22         public void setSession(Session s) {
  23                 assert s != null;
  24                 session = s;
  25         }
  26
  27         protected ResultSet CassandraQuery(String command) {
  28                 try {
  29                         ResultSet results = session.execute(command);
  30                         return results;
  31                 } catch (QueryExecutionException e) {
  32                         String mess = "ProteoCache Cassandra DB interface: query execution exception...\n   Command: " + command;
  33                         System.out.println(mess);
  34                         log.error(mess);
  35                         log.error(e.getLocalizedMessage(), e.getCause());
  36                         return null;
  37                 } catch (QueryValidationException e) {
  38                         String mess = "CProteoCache Cassandra DB interface: query validation exception...\n   Command: " + command;
  39                         System.out.println(mess);
  40                         log.error(mess);
  41                         log.error(e.getLocalizedMessage(), e.getCause());
  42                         return null;
  43                 }
  44
  45         }
  46
  47         /*
  48          * find the earliest date in the database
  49          */
  50         public static long earliestDate() {
  51                 earlestDate = CassandraNativeConnector.getEarliestDateInDB();
  52                 return earlestDate;
  53         }
  54
  55         /**
  56          * prepares an example of either job id or IP for the DB
  57          *
  58          * @param exampletype
  59          *            defines which example you need (an existing job from the DB -
  60          *            jobid, an IP - "ip")
  61          * @return a string representation of the requested example, if the example
  62          *         type is not known empty string is returned
  63          */
  64         public String getExample(String exampletype) {
  65                 if (exampletype.equals("jobid")) {
  66                         return "jp_NzBOJKo";
  67                 } else if (exampletype.equals("ip")) {
  68                         return "127.0.0.1";
  69                 }
  70                 return "";
  71         }
  72
  73 }