src/moteaccess/AbstractMoteAccess.java

   1 package moteaccess;
   2
   3 import java.sql.ResultSet;
   4 import util.SQLHelper;
   5
   6 /** Generic base class for assigning mote usage privileges.
   7  *
   8  * This is an abstract class with the generic code to assign mote usage privileges.
   9  * To integrate any custom reservation system, this class must be inherited and the
  10  * abstract methods implemented.
  11  * @author zept
  12  */
  13 public abstract class AbstractMoteAccess {
  14
  15         /** Acquire mote control privileges using specific session.
  16          *
  17          * @param mote_ids      IDs of mote to control.
  18          * @param session_id    ID of session that wants privileges.
  19          * @return A boolean array with entries for each requested mote.
  20          * @throws Exception
  21          */
  22         public boolean[] getMoteControlPrivileges(long[] mote_ids, String session_id) throws Exception
  23         {
  24                 boolean[] results = new boolean[mote_ids.length];
  25
  26                 for (int i = 0; i < mote_ids.length; i++) {
  27                         results[i] = getMoteControlPrivilege(mote_ids[i], session_id);
  28                 }
  29
  30                 return results;
  31         }
  32
  33         /** Acquire control privilege for one mote.
  34          *
  35          * @param mote_id       ID of mote to control.
  36          * @param session_id    ID of session that wants control privilege.
  37          * @return True if mote control privilege was granted.
  38          * @throws Exception
  39          */
  40         protected boolean getMoteControlPrivilege(long mote_id, String session_id) throws Exception
  41         {
  42                 boolean access = false;
  43                 SQLHelper sql = null;
  44
  45                 try {
  46                         // Check for current privileged session
  47                         String query = "select priv_session_id from mote " +
  48                                        "where id="+mote_id;
  49                         sql = new SQLHelper();
  50                         sql.openDB();
  51                         ResultSet sqlres = sql.retrieve(query);
  52                         if (sqlres.next()){
  53                                 String privsess = sqlres.getString("priv_session_id");
  54                                 if (privsess == null || privsess.compareTo(session_id) == 0) {
  55                                         access = true;
  56                                 } else {
  57                                         // check privileges with reservation system
  58                                         if (hasReservation(mote_id,session_id))
  59                                         {
  60                                                 access = true;
  61                                         }
  62                                 }
  63                         }
  64                         if (access) {
  65                                 query = "update mote set priv_session_id="+session_id+
  66                                         " where id="+mote_id;
  67                                 sql.execute(query);
  68                         }
  69                         return access;
  70
  71                 } finally {
  72                         sql.closeDB();
  73                 }
  74         }
  75
  76         /** Check if session can reserve a given mote.
  77          *
  78          * This method must be implemented to integrate a custom
  79          * reservation system.  It is also a point for integration
  80          * between user account system and reservation system.
  81          *
  82          * Note that the user model should specify the relevant
  83          * reservation key upon session authentication. The details of
  84          * how to do this are application specific.
  85          *
  86          * @param mote_id       Database key for the mote to check
  87          * @param session_id    Database key for the session requesting access.
  88          * @return True if there is a current reservation, false otherwise
  89          * @throws Exception
  90          */
  91         abstract protected boolean hasReservation(long mote_id, String session_id) throws Exception;
  92 }