Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A class that gets Accession Number, check for uniqueness

 *             and register it into db

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

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Jivka Bojilova, Matt Jones

 *    Release: @release@

 *

 *   '$Author: bojilova $'

 *     '$Date: 2001-05-04 09:16:43 -0700 (Fri, 04 May 2001) $'

 * '$Revision: 735 $'

 *

 * 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.net.*;

import java.sql.*;

/**

 * (on insert of XML document)

 * Generates a unique Accession Number or if provided check it 

 * for uniqueness and register it into the db connection 

 * (on update or delete of XML document)

 * Check for existance of provided Accession Number

 * 

 */

public class AccessionNumber  {

  private Connection conn = null;

  private String sitecode = null;

  private String sep = null;

  /** 

   * Construct an AccessionNumber 

   */

  public AccessionNumber () 

         throws SQLException, ClassNotFoundException  

  {

    MetaCatUtil util = new MetaCatUtil();

    this.sitecode = util.getOption("sitecode");

    this.sep = util.getOption("accNumSeparator");

    // Open a connection to the database

    this.conn = util.openDBConnection();

  }  

  /** 

   * Construct an AccessionNumber

   *

   * @param conn the db connection to read from and write Accession# to

   */

  public AccessionNumber (Connection conn) 

  {

    MetaCatUtil util = new MetaCatUtil();

    this.sitecode = util.getOption("sitecode");

    this.sep = util.getOption("accNumSeparator");

    this.conn = conn;

  }

  /**

   * Generate an Accession Number of form <sidecode>.<uniqueid>.<revisionid>

   * where <revisionid> is always 1.

   *

   * @param docid <sitecode>.<uniqueid> part of Accession Number

   * @param action INSERT, UPDATE or DELETE action

   */

  public String generate(String docid, String action) 

                throws AccessionNumberException, SQLException 

  {

    return generate(docid, "1", action);

  }

  /**

   * Generate an Accession Number of form <sidecode>.<uniqueid>.<revisionid>

   *

   * @param docid <sitecode>.<uniqueid> part of Accession Number

   * @param rev <revisionid> of Accession Number

   * @param action INSERT, UPDATE or DELETE action

   */

  public String generate(String docid, String rev, String action) 

                throws AccessionNumberException, SQLException 

  {

    try {

      // INSERT

      if ( action.equals("INSERT")) {

        // get a new docid

        if ( docid == null ) {

          String sitecode = getSitecode();

          String uniqueid = getUniqueID();

          return sitecode + sep + uniqueid;

        // docid is used; throw an exception to prevent the insertion

        } else if ( accNumberUsed(docid) ) {

          throw new AccessionNumberException

                    ("Accession number " + docid + " is already in use.");

        // rev is <> 1; throw an exception to prevent the insertion

        } else if ( !rev.equals("1") ) {

          throw new AccessionNumberException

                    ("Revision number must be 1.");

        // docid is not used and rev=1; return it

        } else {

          return docid;

        }

      // UPDATE or DELETE

      } else if ( action.equals("UPDATE") || action.equals("DELETE")) {

        // Accession# is not provided; throw an exception to prevent the action

        if ( docid == null ) {

          throw new AccessionNumberException("Accession number is required.");

        // Accession# is not current (not in xml_documents); throw an exception

        } else if ( !accNumberIsCurrent(docid) ) {

          throw new AccessionNumberException

          ("Document not found for Accession number " + docid);

        // Revision number is not the recent one; throw an exception

        } else if ( !rev.equals(getLastRevision(docid)) ) {

          throw new AccessionNumberException

          ("Revision number must be the recent.");

        // Accession# is current (present in xml_documents); return it

        } else {

          return docid;

        }

      }

    } catch (SQLException e) {

      throw new SQLException

      ("Error on AccessionNumber.generate(): " + e.getMessage());

    }    

    // never comes here

    throw new

    AccessionNumberException("Fatal Error in accession number generation.");

  }

  // get local sitecode

  private String getSitecode()

  {

    return this.sitecode;

  }

  // get Unique ID from DB sequence

  private String getUniqueID () throws SQLException

  {

    String uniqueid;

    try {

      PreparedStatement pstmt;

      pstmt = conn.prepareStatement

              ("SELECT accnum_uniqueid_seq.nextval FROM dual");

      pstmt.execute();

      ResultSet rs = pstmt.getResultSet();

      boolean hasRow = rs.next();

      uniqueid = rs.getString(1);

      pstmt.close();

    } catch (SQLException e) {

      throw new 

      SQLException("Error on AccessionNumber.getUniqueID(): "+e.getMessage());

    }

    return uniqueid;

  }

  /** check for existence of Accesssion Number xml_acc_numbers table */

  public boolean accNumberUsed ( String accNumber )

                  throws SQLException {

    boolean hasAccNumber = false;

    try {

      PreparedStatement pstmt;

      pstmt = conn.prepareStatement(

                "SELECT 'x' FROM xml_documents " + 

                "WHERE docid LIKE ? " +

                "UNION " +

                "SELECT 'x' FROM xml_revisions " +

                "WHERE docid LIKE ?");

      pstmt.setString(1,accNumber);

      pstmt.setString(2,accNumber);

      pstmt.execute();

      ResultSet rs = pstmt.getResultSet();

      hasAccNumber = rs.next();

      pstmt.close();

    } catch (SQLException e) {

      throw new SQLException

      ("Error on AccessionNumber.accNumberUsed(accNumber): " + e.getMessage());

    }    

    return hasAccNumber;

  }    

  // check for existence of Accesssion Number in xml_documents table

  private boolean accNumberIsCurrent(String accNumber) throws SQLException {

    boolean hasCurrentAccNumber = false;

    try {

      PreparedStatement pstmt;

      pstmt = conn.prepareStatement(

                "SELECT 'x' FROM xml_documents " + 

                "WHERE docid LIKE ?");

      pstmt.setString(1, accNumber);

      pstmt.execute();

      ResultSet rs = pstmt.getResultSet();

      hasCurrentAccNumber = rs.next();

      pstmt.close();

    } catch (SQLException e) {

      throw new SQLException(

          "Error on AccessionNumber.accNumberIsCurrent(String accNumber): " +

          e.getMessage());

    }    

    return hasCurrentAccNumber;

  }    

  // get the recent revision number for docid

  private String getLastRevision(String docid) throws SQLException

  {

    String rev = "";

    try {

      PreparedStatement pstmt;

      pstmt = conn.prepareStatement

              ("SELECT rev FROM xml_documents WHERE docid='" + docid + "'");

      pstmt.execute();

      ResultSet rs = pstmt.getResultSet();

      boolean hasRow = rs.next();

      rev = rs.getString(1);

      pstmt.close();

    } catch (SQLException e) {

      throw new SQLException(

      "Error on AccessionNumber.getLastRevision(): " + e.getMessage());

    }

    return rev;

  }

}