Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A class represent a replication server list in 

               xml_replcation table

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Jing Tao

 *    Release: @release@

 *

 *   '$Author: tao $'

 *     '$Date: 2003-03-19 15:26:44 -0800 (Wed, 19 Mar 2003) $'

 * '$Revision: 1496 $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat;

import java.util.Vector;

import java.sql.*;

/**

 * A class represent a replication server list in xml_replcation table

 */

public class ReplicationServerList

{

  private static Vector serverList = null; //Vector to store server list

  /**

   * constructor of ReplicationServerList

   * It will build server list. If only local host exists, ther server list

   * will be null

   */

  public ReplicationServerList()

  {

    serverList = new Vector();

    //Build serverList

    buildServerList();

  }//ReplicationServerList

  /**

   * Method to create server list from xml_replication table

   * If in xml_replication table, only local host exists, server list will be

   * empty

   */

  private void buildServerList()

  {

    ReplicationServer server = null; //element in server list

    DBConnection dbConn = null;//DBConnection

    int serialNumber = -1;//DBConnection serial number

    PreparedStatement pstmt = null;

    ResultSet rs = null;

    boolean hasReplication = false;//Replication xml or not

    boolean hasDataReplication = false;//Replication data file or not

    boolean isHub = false;//local host is the hub for this server or not

    try

    {

      //Get DBConnection

      dbConn=DBConnectionPool.

                  getDBConnection("ReplicationHandler.buildServerList");

      serialNumber=dbConn.getCheckOutSerialNumber();

      //Select fields from xml_replication table

      pstmt = dbConn.prepareStatement("select server, last_checked, replicate,"+

                    " datareplicate, hub from xml_replication");

      //Execute prepare statement

      pstmt.execute();

      //Get result set

      rs = pstmt.getResultSet();

      //Iterate over the result set

      boolean tableHasRows = rs.next();

      while(tableHasRows)

      {

        //Server name

        String serverName = rs.getString(1);

        MetaCatUtil.debugMessage("ServerName: "+serverName, 40);

        //Last check date

        String lastChecked = rs.getString(2);

        MetaCatUtil.debugMessage("Last checked time: "+lastChecked, 40);

        //Replication value

        int replication = rs.getInt(3);

        MetaCatUtil.debugMessage("Replication value: "+replication, 40);

        //Data replication value

        int dataReplication = rs.getInt(4);

        MetaCatUtil.debugMessage("DataReplication value: "+dataReplication, 40);

        //Hub value

        int hubValue = rs.getInt(5);

        MetaCatUtil.debugMessage("Hub value: "+hubValue, 40);

        //Get rid of local host

        if(!serverName.equals("localhost"))

        {

          //create a new object of Replication

          server = new ReplicationServer();

          //Set server name

          server.setServerName(serverName);

          //Set last check date

          server.setLastCheckedDate(lastChecked);

          //From replication value to determine hasReplication valuse

          if (replication ==1)

          {

            //If replication equals 1, it can replicate xml documents

            hasReplication = true;

          }//if

          else

          {

            //if replication is NOT 1, it can't replicate xml documents

            hasReplication = false;

          }//else

          //Set replication value

          server.setReplication(hasReplication);

          //From both replication and data replication value to determine

          //hasDataReplication value

          if (hasReplication && dataReplication ==1)

          { 

            //Only server can replicate xml (hasRplication == true) and

            // dataReplication is 1, local host can replicate data file

            hasDataReplication = true;

          }//if

          else

          {

            hasDataReplication = false;

          }//else

          //Set data replciation value

          server.setDataReplication(hasDataReplication);

          //Detemine isHub by hubValue

          if (hubValue ==1)

          {

            isHub = true;

          }//if

          else

          {

            isHub = false;

          }//else

          //Set hub value

          server.setHub(isHub);

          //Add this server into server list

          serverList.add(server);

        }//if

        //Go to new row      

        tableHasRows = rs.next();   

      }//while

    }//try

    catch(Exception e)

    {

      MetaCatUtil.debugMessage("Error in ReplicationServerList."

                                    +"buildServerList(): "+e.getMessage(), 30);

    }//catch

    finally

    {

      try

      {

        //close result set

        rs.close();

        //close prepareed statement

        pstmt.close();

      }//try

      catch (SQLException sqlE)

      {

        MetaCatUtil.debugMessage("Error in ReplicationHandler.buildServerList: "

                                +sqlE.getMessage(), 30);

      }//catch

      finally

      {

        //Return dbconnection too pool

        DBConnectionPool.returnDBConnection(dbConn, serialNumber);

      }//finally

    }//finally

  }//buildServerList

  /**

   * Method to determine the server list is empty or not

   */

  public boolean isEmpty()

  {

    return serverList.isEmpty();

  }//isEmpty

  /**

   * Method to get the size of serverList

   */

  public int size()

  {

    return serverList.size();

  }//size()

  /**

   * Method to add a new replciation server object to serverList

   * @Param newReplciationServer, the object need to be add

   */

  private synchronized void addNewReplicationServer

                                      (ReplicationServer newReplicationServer)

  {

    serverList.add(newReplicationServer);

  }//addNewReplicationServer

  /**

   * Method to get a server object given a index number

   * @param index, the given index number

   */

  public ReplicationServer serverAt(int index)

  {

    return (ReplicationServer)serverList.elementAt(index);

  }//serverAt

  /**

   * Method to determine if a given server in the replication server list

   * @param givenServerName, a server name will be check.

   */

  public boolean isGivenServerInList(String givenServerName)

  {

    boolean result = false;//Variable store the return value

    ReplicationServer server = null; //Element in vetor

    int size = 0;//Variable to store the size of vector serverList

    //Get the size of vector

    size = serverList.size();

    //If server list is empty

    if (size == 0||givenServerName == null||givenServerName.equals(""))

    {

      result = false;

      return result;

    }

    //Check every element in the vector

    for (int i = 0; i < size; i++)

    {

      //Get the ReplicationServer object indexed i in vector

      server = (ReplicationServer) serverList.elementAt(i);

      //If given name match a server's name, return true

      if ( givenServerName.equalsIgnoreCase(server.getServerName()))

      {

        result = true;

        return result;

      }//if

    }//for

    //If reach here, there is no server's name match the given name

    //flase will return

    return result;

  }//isGinvenServerInList

  /**

   * Method to determine its index in server list for a given server.

   * If couldn't find it, -1 will be returned

   * @param givenServerName, a server name will be check.

   */

  private synchronized int findIndexInServerList(String givenServerName)

  {

    int index = -1;//Variable store the return value

    ReplicationServer server = null; //Element in vetor

    int size = 0;//Variable to store the size of vector serverList

    //Get the size of vector

    size = serverList.size();

    //If server list is empty, -1 will be returned

    if (size == 0 || givenServerName ==null ||givenServerName.equals(""))

    {

      return index;

    }

    //Check every element in the vector

    for (int i = 0; i < size; i++)

    {

      //Get the ReplicationServer object indexed i in vector

      server = (ReplicationServer) serverList.elementAt(i);

      //If given name match a server's name, return true

      if ( givenServerName.equalsIgnoreCase(server.getServerName()))

      {

        index = i;

        return index;

      }//if

    }//for

    //If reach here, there is no server's name match the given name

    //-1 will return

    return index;

  }//isGinvenServerInList

  /**

   * To a given server name, try to get its lastcheck date.

   * If couldn't find the server in the server list, null will return

   * @param givenServerName, the server's name which we want to get last checked

   * out date

   */

  public synchronized String getLastCheckedDate(String givenServerName)

  {

    int index = -1;//Variable to store the index

    ReplicationServer server = null;//Variable for replication server

    //Get the server's index in server list

    index = findIndexInServerList(givenServerName);

    //If index = -1, couldn't find this server, null will return

    if (index == -1)

    {

      return null;

    }//if

    //Get Replication server object

    server = (ReplicationServer) serverList.elementAt(index);

    //return its lastcheckeddate attributes in this object

    return server.getLastCheckedDate();

  }//getLastCehckedDate

  /**

   * To a given server name, try to get its xml replciation option

   * If couldn't find the server in the server list, false will return

   * @param givenServerName, the server's name which we want to get replication

   * value

   */

  public synchronized boolean getReplicationValue(String givenServerName)

  {

    int index = -1;//Variable to store the index

    ReplicationServer server = null;//Variable for replication server

    //Get the server's index in server list

    index = findIndexInServerList(givenServerName);

    //If index = -1, couldn't find this server, null will return

    if (index == -1)

    {

      return false;

    }//if

    //Get Replication server object

    server = (ReplicationServer) serverList.elementAt(index);

    //return this object's replication value

    return server.getReplication();

  }//getReplicationValue

  /**

   * To a given server name, try to get its data file replciation option

   * If couldn't find the server in the server list, false will return

   * @param givenServerName, the server's name which we want to get data file 

   * replication value

   */

  public synchronized boolean getDataReplicationValue(String givenServerName)

  {

    int index = -1;//Variable to store the index

    ReplicationServer server = null;//Variable for replication server

    //Get the server's index in server list

    index = findIndexInServerList(givenServerName);

    //If index = -1, couldn't find this server, null will return

    if (index == -1)

    {

      return false;

    }//if

    //Get Replication server object

    server = (ReplicationServer) serverList.elementAt(index);

    //Return this object's data replication value

    return server.getDataReplication();

  }//getDataReplicationValue

  /**

   * To a given server name, try to get its hub option

   * If couldn't find the server in the server list, false will return

   * @param givenServerName, the server's name which we want to get hub

   */

  public synchronized boolean getHubValue(String givenServerName)

  {

    int index = -1;//Variable to store the index

    ReplicationServer server = null;//Variable for replication server

    //Get the server's index in server list

    index = findIndexInServerList(givenServerName);

    //If index = -1, couldn't find this server, null will return

    if (index == -1)

    {

      return false;

    }//if

    //Get Replication server object

    server = (ReplicationServer) serverList.elementAt(index);

    //Return this object's hub value

    return server.getHub();

  }//getHubValue  

  /**

   * To a given server name, to check if it is in the server list.

   * If it is not, add it to server list and the xml_replication table

   * This method is for a document was replicated by a hub and the document's

   * home server is not in the replication table. The value for replicate,

   * datareplicate and hub are all false

   * @param givenServerName, the server's name which want to check

   */

  public synchronized void addToServerListIfItIsNot(String givenServerName)

  {

    // Variable to store the index for the givenServerName

    int index = -1;

    // Variable to store the new replciation server object

    ReplicationServer newServer = null;

    // For sql command

    PreparedStatement pStmt=null;

    // For check out DBConnection

    DBConnection dbConn = null;

    int serialNumber = -1;

    // Field value for xml_replication table

    int replicate = 0;

    int dataReplicate = 0;

    int hub = 0;

    // Get the the index

    index = findIndexInServerList(givenServerName);

    // if index ==-1, it not in the server list

    // Add the server to server list

    // Add the server to xml_replication table

    if (index ==-1)

    {

      // Create a new replication server object it's replicate, datareplicate

      // and hub values are default - false

      newServer = new ReplicationServer();

      // Set newServer's name as givenServerName

      newServer.setServerName(givenServerName);

      // Add newServer to serverList

      this.addNewReplicationServer(newServer);

      // Add this server to xml_table too

     try

      {

        // Checkout DBConnection     

        dbConn=DBConnectionPool.

             getDBConnection("ReplicationSErverList.addToServerListIfItIsNot");

        serialNumber=dbConn.getCheckOutSerialNumber();

        // Inser it into xml_replication table

        pStmt = dbConn.prepareStatement("INSERT INTO xml_replication " +

                      "(server, last_checked, replicate, datareplicate, hub) "+

                       "VALUES ('" + givenServerName + "', to_date(" +

                       "'01/01/00', 'MM/DD/YY'), '" +

                       replicate +"', '"+dataReplicate+"','"+ hub + "')");

        pStmt.execute();

        pStmt.close();

      }//try

      catch (Exception e)

      {

        MetaCatUtil.debugMessage("Error in ReplicationServerList."+

                            "addToServerListIfItIsNot: " + e.getMessage(), 30);

      }//catch

      finally

      { 

        try

        {

          pStmt.close();

        }//try

        catch (Exception ee)

        { 

          MetaCatUtil.debugMessage("Error in ReplicationServerList."+

                            "addToServerListIfItIsNot: " + ee.getMessage(), 50);

        }//catch

        finally

        {

          DBConnectionPool.returnDBConnection(dbConn, serialNumber);

        }//finally

      }//finally

    }//if

  }//addToServerListIfItIsNot

}//ReplicationServerList