Question

This code has caused me lots of trouble so far but it’s really first class I write to use preparedStatement, Oracle, and serialization. So I am asking for your patience.
The following is the code:

 public static boolean storeInfo(Reservation rsv) throws
        IOException, SQLException{
    try {
          //Connection to DB
          Connection con = null;
          Class.forName("oracle.jdbc.driver.OracleDriver");
          con=DriverManager.getConnection(
            "jdbc:oracle:thin:@odsdsd",
            "SMBDB",
            "hpdbsmb");
          con.setAutoCommit(false);
          ByteArrayOutputStream bos = new ByteArrayOutputStream() ;
          ObjectOutputStream out = new ObjectOutputStream(bos);
          out.writeObject(rsv);
          out.flush();
          out.close();
          byte[] buf = bos.toByteArray();
          //inserting into database
          PreparedStatement prepareStatement = con.prepareStatement("INSERT INTO 
           SMD_RESERVATION_INSTANCES VALUES(?,?,?)");
          localIDTest = getUniqueID();
          System.out.println("ID: "+localIDTest);
          prepareStatement.setString(1, localIDTest);
          prepareStatement.setBytes(2, buf);
          prepareStatement.setString(3, "Pending");
          prepareStatement.executeUpdate();
          prepareStatement.close();
          con.commit();
   }catch(SQLException sqle){
       System.err.print(sqle);
   }
   catch(ClassNotFoundException cnfe){
       System.err.print(cnfe);
   }
    return false;
   }


   public static Reservation retrieveReservation()throws IOException,
        SQLException{
   Reservation testRsv = new Reservation();
   try {
        Connection con = null;

        Class.forName("oracle.jdbc.driver.OracleDriver");
        con=DriverManager.getConnection(
            "jdbc:oracle:thin:@dsdsds",
            "SMBDB",
            "hpdbsmb");
        con.setAutoCommit(false);
       try {

            PreparedStatement prepareStatement = con.prepareStatement("SELECT * FROM 
             SMD_RESERVATION_INSTANCES WHERE id = ?");         
            prepareStatement.setString(1, localIDTest);
            ResultSet rset = prepareStatement.executeQuery();
            prepareStatement.executeUpdate();
            //prepareStatement.close();
            con.commit();
            if(rset.next()){
                retrievedID = rset.getString("ID");
                Blob blob = rset.getBlob("RESERVATIONINST");
                status = rset.getString("STATUS");
                long blobLength = blob.length();
                int pos = 1;   // position is 1-based
                //int len = 10;
                byte[] bytes = blob.getBytes(pos,(int) blobLength);
                InputStream is = blob.getBinaryStream();
                ObjectInputStream ois = new ObjectInputStream(is);
                testRsv=(Reservation)ois.readObject();
            }


        rset.close();
        con.close();
         }catch(IOException ioe){
              System.err.print(ioe);
          }
       }catch(ClassNotFoundException cnfe){
          System.err.print(cnfe);
      }
    return testRsv;

   }

   public static void displayRsvContent(){

    try{
        Reservation rsvtester = new Reservation();
        rsvtester.badgeNo = 750752;
        rsvtester.networkID = "GHAMKS1C";
        storeInfo(rsvtester);
        rsvReturned = retrieveReservation();
        if(rsvReturned == null){
            System.out.println("Null Reservation!");
        }else{
            System.out.println("Badge: " + rsvReturned.badgeNo);
            System.out.println("Network: " + rsvReturned.networkID);
        }

    }catch(SQLException sqle){
            System.err.print(sqle);
    }catch(IOException ioe){
        System.err.print(ioe);
    }
  }


public static void main(String[]args){
    displayRsvContent();
}

This is just testing that storing and retrieving the object is done correctly. I create an instance of Reservation and assign its variables values to see if they are actually saved. Surprise surprise they aren’t showing up when loading. This is what I get:

ID: ec561507-7138-4468-98a3-7756219f216e
Badge: 0
Network: null

Why is this happening even though am simply assigning it before storing the object? The id shows though is correct.

P.S. Reservation:

public class Reservation implements
   java.io.Serializable{

String eventTitle;
public Date startDate;
public Date endDate;
String requestType;
public int terminals;
String lastName;
String firstName;
String middleInitials;
public transient int badgeNo;
public transient String networkID;
String telephoneNo;
String orgCode;
String orgName;
String justification;
String insideCheckRange;
int mapSize;



MapStorage mapStorage = new MapStorage();


public Reservation(int badgeNo, String networkID) {
    this.badgeNo = badgeNo;
    this.networkID = networkID;
}


    public Reservation(){

    }

public Reservation(String eventTitle, Date startDate, Date endDate, String requestType, int terminals, String lastName, String firstName, String middleInitials, int badgeNo, String networkID, String telephoneNo, String orgCode, String justification) {
    //create in here

    this.eventTitle = eventTitle;
    this.startDate = startDate;
    this.endDate = endDate;
    this.requestType = requestType;
    this.terminals = terminals;
    this.lastName = lastName;
    this.firstName = firstName;
    this.middleInitials = middleInitials;
    this.badgeNo = badgeNo;
    this.networkID = networkID;
    this.telephoneNo = telephoneNo;
    this.orgCode = orgCode;
    this.justification = justification;
}



 public boolean checkRange() {    



        DateTime startx = new DateTime(startDate.getTime());
        DateTime endx = new DateTime(endDate.getTime());

        //booking status
        boolean possible = false;

        //Booking type: 1 = Project, 2 = Training

        /*
        if(requestType.equals("Project")){
            bookingType = 1;
        }else if(requestType.equals("Training")){
            bookingType = 2;

        }
        */
        //produces submap
        //mapSize = bookingType;
        TreeMap<DateTime, Integer> mapLoaded = null;
        try{
         mapLoaded = mapStorage.RetrieveMap();
        }catch(IOException ioe)
        {
            System.err.print(ioe);
        }
        if(requestType.equals("Project"))
        {
            //Project
            //insideCheckRange = "In first for loop";
            //fetch all values for keys in the map between start and end
                for (Integer capacity : mapLoaded.subMap(startx, endx).values()) {


                    if(capacity >= terminals)
                        //yes then its possible, set to true
                        possible = true;
                    else if(capacity < terminals)
                        //not then set it to false
                        possible = false;

                }

                if(possible == true)
                {

                    //if it is possible to accomodate request
                    for (DateTime x : mapLoaded.subMap(startx, endx).keySet()) {
                    {
                        //for dates n, update value for next operation
                        mapLoaded.put(x, mapLoaded.get(x) - terminals);
                    }
                }
                }else{
                 //nothing now
                }
        }else if(requestType.equals("Training")){
            //Training
             for (Integer capacity : mapLoaded.subMap(startx, endx).values()) {
                    //Provides an insight into capacity accomodation possibility
                    //testValue++;
                    terminals = 1;
                    if(capacity >= terminals)
                        possible = true;
                    else if(capacity < terminals)
                        possible = false;

                }


                if(possible == true)
                {
                    for (DateTime x : mapLoaded.subMap(startx, endx).keySet()) {
                    {
                        //46 so that all seats are reserved
                        mapLoaded.put(x, mapLoaded.get(x) - 46);

                    }
                }
                }else{
                 //nothing now
                }

        }


        return possible;
}

}

Answer 1

If you have transient fields in Reservation that would explain it.

But, I think that the problem is that you are actually displaying the dummy Reservation that you created at the start of retrieveReservation().

Why? Because rset.next() is returning false.

Why? Well take a look at this:

   PreparedStatement prepareStatement = con.prepareStatement("SELECT * FROM 
         SMD_RESERVATION_INSTANCES WHERE id = ?");         
   prepareStatement.setString(1, localIDTest);
   ResultSet rset = prepareStatement.executeQuery();
   prepareStatement.executeUpdate();
   //prepareStatement.close();
   con.commit();

That’s pretty random. You don’t need to do both an executeQuery and an executeUpdate on the same prepared statement. And there’s no need to commit() at that point because this is a query!

So, what I think is happening is that your spurious call to executeUpdate is closing the ResultSet so that when you call rset.next() it is returning false. (Another possible cause of rset.next() returning false would be if your earlier insert had failed / not committed.)

Anyway, if rset.next() returns false, your code doesn’t even try to deserialize a retrieved object … and you end up returning the dummy object.