Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A class to asyncronously do delta-T replication checking

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

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Chad Berkley

 *    Release: @release@

 *

 *   '$Author$'

 *     '$Date$'

 * '$Revision$'

 * 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.sql.*;

import java.util.*;

import java.lang.Thread;

import java.io.*;

import java.net.*;

import org.xml.sax.ContentHandler;

import org.xml.sax.DTDHandler;

import org.xml.sax.EntityResolver;

import org.xml.sax.ErrorHandler;

import org.xml.sax.InputSource;

import org.xml.sax.XMLReader;

import org.xml.sax.SAXException;

import org.xml.sax.SAXParseException;

import org.xml.sax.helpers.XMLReaderFactory;

 * This class handles deltaT replication checking.  Whenever this TimerTask

 * is fired it checks each server in xml_replication for updates and updates

 * the local db as needed.

 */

public class ReplicationHandler extends TimerTask

{

  public ReplicationHandler(PrintWriter o)

  {

    this.out = o;

  {

    this.out = o;

    this.serverCheckCode = serverCheckCode;

   * Method that implements TimerTask.run().  It runs whenever the timer is

   * fired.

   */

  public void run()

  {

    //find out the last_checked time of each server in the server list and

    //send a query to each server to see if there are any documents in

    //xml_documents with an update_date > last_checked

    try

    {

      if (serverList==null||serverList.isEmpty())

      {

        return;

      }

      update();

    }//try

    {

                                                    +e.getMessage(), 30);

  /**

   */

    /*

     Pseudo-algorithm

     - request a doc list from each server in xml_replication

     - check the rev number of each of those documents agains the

       documents in the local database

     - pull any documents that have a lesser rev number on the local server

       from the remote server

     - delete any documents that still exist in the local xml_documents but

       are in the deletedDocuments tag of the remote host response.

     - update last_checked to keep track of the last time it was checked.

       (this info is theoretically not needed using this system but probably

       should be kept anyway)

    */

                                        // ReplicationServer got from

                                        // Server list

    String server; // Variable to store server name

    ReplMessageHandler message = new ReplMessageHandler();

    Vector responses = new Vector();

    XMLReader parser;

    URL u;

    {

      parser = initParser(message);

    catch (Exception e)

    {

      MetacatReplication.replErrorLog("Failed to replicate becaue couldn't "+

                                 " initParser for message and" +e.getMessage());

      MetaCatUtil.debugMessage("Failed to replicate becaue couldn't " +

                            " initParser for message and " +e.getMessage(), 30);

       // stop replication

       return;

    }

    //Check for every server in server list to get updated list and put

    // them in to response

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

    {

        replServer = serverList.serverAt(i);

        // Get server name from ReplicationServer object

        server = replServer.getServerName();

        try

        {

          +util.getLocalReplicationServerName()+"&action=update");

          MetaCatUtil.debugMessage("Sending infomation " +u.toString(), 50);

        {

                          "for server " + server + " because "+e.getMessage());

          MetaCatUtil.debugMessage( "Failed to get updated doc list "+

                       "for server " + server + " because "+e.getMessage(), 30);

        //check if result have error or not, if has skip it.

                          "for server " + server + " because "+result);

          MetaCatUtil.debugMessage( "Failed to get updated doc list "+

                       "for server " + server + " because "+result, 30);

        }

    //If response is null, metacat don't need do anything

    if (responses==null || responses.isEmpty())

    {

        MetacatReplication.replErrorLog("No updated doc list for "+

                           "every server and failed to replicate");

        MetaCatUtil.debugMessage( "No updated doc list for "+

                           "every server and failed to replicate", 30);

                   "document information: "+ responses.toString(), 35);

    // go through response vector(it contains updated vector and delete vector

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

    {

        try

        {

          parser.parse(new InputSource(

                     (String)(responses.elementAt(i)))));

        catch(Exception e)

        {

          MetacatReplication.replErrorLog("Couldn't parse one responses "+

                           "because "+ e.getMessage());

          MetaCatUtil.debugMessage("Couldn't parse one responses "+

                                   "because "+ e.getMessage(), 30);

          continue;

        }

        MetaCatUtil.debugMessage("Delete vector size: "+ deleteList.size(),40);

        // go though every element in updated document vector

        for(int j=0; j<updateList.size(); j++)

          dataFile=false;

          //w is information for one document, information contain

          //docid, rev, server or datafile.

          //If it has, this document is data file

          if (w.contains((String)util.getOption("datafileflag")))

          {

            dataFile=true;

          }

          // the new hub feature

          String remoteServer = (String)w.elementAt(2);

          // compare the update rev and local rev to see what need happen

          int localrev = -1;

          try

          {

            localrev = DocumentImpl.getLatestRevisionNumber(docid);

          }

          catch (SQLException e)

          {

            MetaCatUtil.debugMessage("Local rev for docid "+ docid + " could not "+

                                   " be found because " + e.getMessage(), 45);

            MetacatReplication.replErrorLog("Docid "+ docid + " could not be "+

                    "written because error happend to find it's local revision");

            continue;

          }

          MetaCatUtil.debugMessage("Local rev for docid "+ docid + " is "+

                                  localrev, 45);

          //check the revs for an update because this document is in the

          //local DB, it might be out of date.

          if (localrev == -1)

          {

            //insert this document as new because it is not in the local DB

            action = "INSERT";

            flag = true;

          }

          else

          {

            {

              // update and flag set false

            }

            else if(localrev < rev)

              //this document needs to be updated so send an read request

              flag = true;

            }

          }

          if(flag && !dataFile)

            {

            catch(Exception e)

            {

              continue;

          if(flag && dataFile)

            try

            {

            }

            {

              continue;

            }

        }//for update docs

          String docId = (String)w.elementAt(0);

          try

          {

            continue;

          }

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

    {

       // Get ReplicationServer object from server list

       replServer = serverList.serverAt(i);

       try

       {

         updateLastCheckTimeForSingleServer(replServer);

       }

       catch(Exception e)

       {

         continue;

       }

    }//for

  }//update

  /* Handle replicate single xml document*/

  private void handleSingleXMLDocument(String remoteserver, String actions,

                                       String docId)

               throws Exception

  {

    DBConnection dbConn = null;

    int serialNumber = -1;

    try

    {

      // Get DBConnection from pool

      dbConn=DBConnectionPool.

                  getDBConnection("ReplicationHandler.handleSingleXMLDocument");

      serialNumber=dbConn.getCheckOutSerialNumber();

      //if the document needs to be updated or inserted, this is executed

              util.getLocalReplicationServerName()+"&action=read&docid="+docId;

      readDocURLString = MetaCatUtil.replaceWhiteSpaceForURL(readDocURLString);

      URL u = new URL(readDocURLString);

      // Get docid content

      String newxmldoc = MetacatReplication.getURLContent(u);

      // If couldn't get skip it

      }

      MetaCatUtil.debugMessage("xml documnet:", 45);

      MetaCatUtil.debugMessage(newxmldoc, 45);

      // Try get the docid info from remote server

      DocInfoHandler dih = new DocInfoHandler();

      XMLReader docinfoParser = initParser(dih);

      docInfoURLStr = MetaCatUtil.replaceWhiteSpaceForURL(docInfoURLStr);

      URL docinfoUrl = new URL(docInfoURLStr);

                                                  docinfoUrl.toString(), 45);

      String docInfoStr = MetacatReplication.getURLContent(docinfoUrl);

      docinfoParser.parse(new InputSource(new StringReader(docInfoStr)));

      Hashtable docinfoHash = dih.getDocInfo();

      // Get home server of the docid

      String docHomeServer = (String)docinfoHash.get("home_server");

      MetaCatUtil.debugMessage("doc home server in repl: "+docHomeServer, 45);

      //docid should include rev number too

      String accnum=docId+util.getOption("accNumSeparator")+

                                              (String)docinfoHash.get("rev");

      MetaCatUtil.debugMessage("docid in repl: "+accnum, 45);

      String docType = (String)docinfoHash.get("doctype");

      MetaCatUtil.debugMessage("doctype in repl: "+docType, 45);

      String parserBase = null;

      // this for eml2 and we need user eml2 parser

      if (docType != null && (docType.trim()).equals(DocumentImpl.EMLNAMESPACE))

      {

         parserBase = DocumentImpl.EML2;

      }

      // Write the document into local host

      DocumentImplWrapper wrapper = new DocumentImplWrapper(parserBase, false);

      String newDocid = wrapper.writeReplication(dbConn,

                              new StringReader(newxmldoc),

                              (String)docinfoHash.get("public_access"),

                              null,  /* the dtd text */

                              actions,

                              accnum,

                              (String)docinfoHash.get("user_owner"),

                              null, /* null for groups[] */

                              docHomeServer,

                              remoteserver);

      MetaCatUtil.debugMessage("Successfully replicated doc " + accnum, 35);

      MetacatReplication.replLog("wrote doc " + accnum + " from " +

                                         remoteserver);

    }//try

    {

                                      " into db because " +e.getMessage());

      MetaCatUtil.debugMessage("Failed to write doc " + docId +

                                      " into db because " +e.getMessage(), 30);

      throw e;

    {

       DBConnectionPool.returnDBConnection(dbConn, serialNumber);

    }//finally

  }

  /* Handle replicate single xml document*/

  private void handleSingleDataFile(String remoteserver, String actions,

                                    String docId)

               throws Exception

  {

    MetaCatUtil.debugMessage("Try to replicate data file: "+docId, 40);

    DBConnection dbConn = null;

    int serialNumber = -1;

    try

    {

      // Get DBConnection from pool

      dbConn=DBConnectionPool.

                  getDBConnection("ReplicationHandler.handleSinlgeDataFile");

      serialNumber=dbConn.getCheckOutSerialNumber();

      // Try get docid info from remote server

      DocInfoHandler dih = new DocInfoHandler();

      XMLReader docinfoParser = initParser(dih);

      docInfoURLString = MetaCatUtil.replaceWhiteSpaceForURL(docInfoURLString);

      URL docinfoUrl = new URL(docInfoURLString);

      docinfoParser.parse(new InputSource(new StringReader(docInfoStr)));

      Hashtable docinfoHash = dih.getDocInfo();

      // Get doicd owner

      String user = (String)docinfoHash.get("user_owner");

      // Get docid name (such as acl or dataset)

      String docName = (String)docinfoHash.get("docname");

      // Get doc type (eml public id)

      String docType = (String)docinfoHash.get("doctype");

      // Get docid home sever. it might be different to remoteserver

      // becuause of hub feature

      String docHomeServer = (String)docinfoHash.get("home_server");

      //docid should include rev number too

      String accnum=docId+util.getOption("accNumSeparator")+

                                              (String)docinfoHash.get("rev");

      // Get data file content

      readDataURLString = MetaCatUtil.replaceWhiteSpaceForURL(readDataURLString);

      URL u = new URL(readDataURLString);

      InputStream input = u.openStream();

      //into file system

                                                        docName,docType,

                                                        accnum, user,

                                                        docHomeServer,

                                                        remoteserver);

        MetaCatUtil.debugMessage("Successfully to write datafile " + docId, 30);

        MetacatReplication.replLog("wrote datafile " + accnum + " from " +

                                    remoteserver);

      }//if

      else

      }//else

    }//try

    catch(Exception e)

    {

      MetacatReplication.replErrorLog("Failed to try wrote datafile " + docId +

                                      " because " +e.getMessage());

      MetaCatUtil.debugMessage("Failed to try wrote datafile " + docId +

                                      " because " +e.getMessage(), 30);

      throw e;

    }

    finally

    {

       //return DBConnection

       DBConnectionPool.returnDBConnection(dbConn, serialNumber);

    }//finally

  }

  /* Handle delete single document*/

  private void handleDeleteSingleDocument(String docId)

               throws Exception

  {

    MetaCatUtil.debugMessage("Try delete doc: "+docId, 40);

    DBConnection dbConn = null;

    int serialNumber = -1;

    try

    {

      // Get DBConnection from pool

      dbConn=DBConnectionPool.

                  getDBConnection("ReplicationHandler.handleDeleteSingleDoc");

      serialNumber=dbConn.getCheckOutSerialNumber();

      if(!alreadyDeleted(docId))

         //because delete method docid should have rev number

         //so we just add one for it. This rev number is no sence.

         String accnum=docId+util.getOption("accNumSeparator")+"1";

         //System.out.println("accnum: "+accnum);

         DocumentImpl.delete(accnum, null, null);

         MetaCatUtil.debugMessage("Successfully deleted doc " + docId, 30);

         MetacatReplication.replLog("Doc " + docId + " deleted");

      }

    }//try

    catch(Exception e)

    {

      MetacatReplication.replErrorLog("Failed to delete doc " + docId +

                                      " in db because " +e.getMessage());

      MetaCatUtil.debugMessage("Failed to delete doc " + docId +

                                 " in db because because " +e.getMessage(), 30);

      throw e;

    }

    finally

    {

       //return DBConnection

       DBConnectionPool.returnDBConnection(dbConn, serialNumber);

  private void updateLastCheckTimeForSingleServer(ReplicationServer repServer)

                                                  throws Exception

    int serialNumber = -1;

    PreparedStatement pstmt = null;

    {

      // Get time from remote server

      URL dateurl = new URL("https://" + server + "?server="+

      util.getLocalReplicationServerName()+"&action=gettime");

      String datexml = MetacatReplication.getURLContent(dateurl);

      MetaCatUtil.debugMessage("datexml: "+datexml, 45);

      if (datexml!=null && !datexml.equals(""))

      {

         String datestr = datexml.substring(11, datexml.indexOf('<', 11));

         StringBuffer sql = new StringBuffer();

         sql.append("update xml_replication set last_checked = to_date('");

         sql.append(datestr).append("', 'YY-MM-DD HH24:MI:SS') where ");

         sql.append("server like '").append(server).append("'");

         //System.out.println("sql: " + sql.toString());

         pstmt = dbConn.prepareStatement(sql.toString());

         pstmt.executeUpdate();

         dbConn.commit();

         pstmt.close();

         MetaCatUtil.debugMessage("last_checked updated to "+datestr+" on "

                                      + server, 45);

      }//if

      else

      {

         MetaCatUtil.debugMessage("Failed to update last_checked for server "  +

                                  server + " in db because couldn't get time "

                                  , 30);

         throw new Exception("Couldn't get time for server "+ server);

      }

    }//try

    catch(Exception e)

    {

      MetaCatUtil.debugMessage("Failed to update last_checked for server " +

                                server + " in db because because " +

                                e.getMessage(), 30);

      throw e;

    }

    finally

    {

       //return DBConnection

       DBConnectionPool.returnDBConnection(dbConn, serialNumber);

    }//finally

  }

  /**

   * updates xml_catalog with entries from other servers.

   */

  private void updateCatalog()

  {

    MetaCatUtil.debugMessage("Start of updateCatalog", 35 );

    // ReplicationServer object in server list

    ReplicationServer replServer = null;

    PreparedStatement pstmt = null;

    String server = null;

    // Go through each ReplicationServer object in sererlist

    for (int j=0; j<serverList.size(); j++)

    {

      Vector remoteCatalog = new Vector();

      Vector publicId = new Vector();

      try

      {

        replServer = serverList.serverAt(j);

        // Get server name from the ReplicationServer object

        server = replServer.getServerName();

        // Try to get catalog

        // Make sure there are not error, no empty string

        if (catxml.indexOf("error")!=-1 || catxml==null||catxml.equals(""))

        {

        XMLReader catparser = initParser(cmh);

        catparser.parse(new InputSource(new StringReader(catxml)));

        //parse the returned catalog xml and put it into a vector

        if (remoteCatalog.isEmpty())

        {

        // Make sure local catalog is no empty

        if (localcatxml==null||localcatxml.equals(""))

        {

        catparser = initParser(cmh);

        catparser.parse(new InputSource(new StringReader(localcatxml)));

        Vector localCatalog = cmh.getCatalogVect();

        //now we have the catalog from the remote server and this local server

        //we now need to compare the two and merge the differences.

        //the comparison is base on the public_id fields which is the 4th

        //entry in each row vector.

        {

          Vector v = new Vector((Vector)localCatalog.elementAt(i));