Metacat

/**

 *   '$Author: tao $'

 *     '$Date: 2003-04-26 15:19:22 -0700 (Sat, 26 Apr 2003) $'

 * '$Revision: 1619 $'

 *

 * 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 edu.ucsb.nceas.morpho.datapackage.Triple;

import edu.ucsb.nceas.morpho.datapackage.TripleCollection;

import java.io.StringReader;

import java.sql.*;

import java.util.*;

import java.net.*;

public class RelationHandler //implements Runnable

{

  private DBConnection connection = null;

  private String docid = null;

  private String docType = null;

  TripleCollection tripleForPackage = null;

  /** 

   * Constructor for this class.  finds all of the relations to a single xml

   * document and writes them to the database.  This includes transitive

   * relations.

   * @param docid the ID of the XML document to index.

   * @param doctype the doctype of this document

   * @param conn the db connection

   * @param list the triple list

   */

  public RelationHandler(String docid, String doctype, 

                        DBConnection conn, TripleCollection list)

              throws McdbException, SQLException, AccessionNumberException

  {

    this.connection = conn;

    this.docid = docid;

    this.docType = doctype;

    tripleForPackage = list;

    createRelations();

  }

   /**

   * insert the relations specified in the triples into xml_relation table

   */ 

  private void createRelations() 

              throws McdbException, SQLException, AccessionNumberException

  {

    String packagetype = docType;

    String subject = null;

    String subjectParentId = null;

    String subDoctype = null;

    String relationship = null;

    String relationshipParentId = null;

    String object = null;

    String objDoctype = null;

    PreparedStatement tstmt = null; // to insert each relation into xml_relation

    MetaCatUtil.debugMessage("Running relation handler!", 40);

    // first delete the relations for this package document if any

    deleteRelations(docid);

    //get the vetor of triples 

    Vector tripleList= new Vector();

    //get vector form tripleCollection

    if (tripleForPackage != null)

    {

      tripleList =tripleForPackage.getCollection();

    }

    if (tripleList != null && tripleList.size()>0) 

    {

       tstmt = connection.prepareStatement("INSERT INTO xml_relation (" +

                                    "docid,packagetype,subject,subdoctype," +

                                    "relationship, object, objdoctype) " + 

                                    "VALUES (?, ?, ?, ?, ?, ?, ?)");

      // go through tripe list 

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

      {

        //increase usage count

        connection.increaseUsageCount(1);

        // Get the triple

        Triple triple = (Triple)tripleList.elementAt(i);

        MetaCatUtil.debugMessage("Info from triple: ", 30);

        MetaCatUtil.debugMessage("subject from triple:"+triple.getSubject(), 30);

        MetaCatUtil.debugMessage("relationship from triple:"+triple.getRelationship(),30);

        MetaCatUtil.debugMessage("object from triple: "+triple.getObject(),30);

        //subject = (new DocumentIdentifier(triple.getSubject())).getIdentifier();

        subject = MetaCatUtil.getDocIdFromString(triple.getSubject());

        relationship = triple.getRelationship();

        //object = (new DocumentIdentifier(triple.getObject())).getIdentifier();

        object = MetaCatUtil.getDocIdFromString(triple.getObject());

        if (subject != null && relationship != null && object != null)

        {

          //put the new relation into xml_relation

          MetaCatUtil.debugMessage("Insert into xml_relation table", 30);

          tstmt.setString(1, docid);

          MetaCatUtil.debugMessage("Insert docid into xml_relation table" + 

                                docid, 30);

          tstmt.setString(2, packagetype);

          tstmt.setString(3, subject);

          MetaCatUtil.debugMessage("Insert subject into xml_relation table" + 

                               subject, 30);

          tstmt.setString(4, subDoctype);

          tstmt.setString(5, relationship);

          MetaCatUtil.debugMessage("Insert relationship into xml_relation table" + 

                                relationship, 30);

          tstmt.setString(6, object);

          MetaCatUtil.debugMessage("Insert object into xml_relation table" + 

                                object, 30);

          tstmt.setString(7, objDoctype);

          tstmt.execute();  

        }//if

      }//for

    }//if

    if ( tstmt != null ) 

    {

      tstmt.close();

    }

  }

  /**

   * Deletes all of the relations with a docid of 'docid'.

   * @param docid the docid of the package which relations to delete.

   */

  public void deleteRelations(String docid) throws SQLException

  {

    try {

      PreparedStatement pstmt = connection.prepareStatement(

                                "DELETE FROM xml_relation " +

                                "WHERE docid = '" + docid + "'");

      //increase usage count

      connection.increaseUsageCount(1);

      pstmt.execute();

      pstmt.close();

    } catch(SQLException e) {

      MetaCatUtil.debugMessage("error in RelationHandler.deleteRelations(): " + 

                          e.getMessage(), 30);

      throw e;

    }

  }

  /**

   * Get the access file id for a package

   * @param docid the document identifier of the package

   * @return the document identifier of the access file for that package

   */

  public static String getAccessFileID(String docid) throws SQLException

  {

    String aclid = null;

    PreparedStatement pstmt = null;

    DBConnection dbConn = null;

    int serialNumber = -1;

    StringBuffer sql = new StringBuffer();

    sql.append("SELECT docid FROM xml_documents WHERE docid in (SELECT subject ");

    sql.append("FROM xml_relation WHERE docid='").append(docid);

    sql.append("' AND (");

    Vector accessdoctypes = MetaCatUtil.getOptionList(

                              MetaCatUtil.getOption("accessdoctype"));

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

    {

      String atype = (String)accessdoctypes.elementAt(i);

      sql.append("doctype='").append(atype).append("'");

      if(i < accessdoctypes.size()-1)

      {

        sql.append(" OR ");

      }

    }

    sql.append("))");

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

    try

    {

      dbConn=DBConnectionPool.

                  getDBConnection("RelationHandler.getAccessFileID");

      serialNumber=dbConn.getCheckOutSerialNumber();

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

      pstmt.execute();

      ResultSet rs = pstmt.getResultSet();

      boolean hasRow = rs.next();

      if (hasRow) {

        aclid = rs.getString(1);

      }

      pstmt.close();

    }//try

    finally

    {

      try

      {

        pstmt.close();

      }//try

      finally

      {

        DBConnectionPool.returnDBConnection(dbConn, serialNumber);

      }//finally

    }//finally

    MetaCatUtil.debugMessage("The access docid get from xml_relation is: "+

                              aclid, 30);

    return aclid;

  }

}