jahiaincrementorsdbbaseservice.java

java 写的一个新闻发布系统

//
//  JahiaIncrementorsDBBaseService
//  EV      02.11.2000
//
//  autoIncrement()
//

package org.jahia.services.database;

import java.sql.*;                  // ResultSet
import org.jahia.registries.*;  // JahiaConsole
import org.jahia.utils.*;       // JahiaConsole
import org.jahia.exceptions.JahiaException;

import org.jahia.data.JahiaDOMObject;
import org.jahia.data.JahiaDBDOMObject;


public class JahiaIncrementorsDBBaseService extends JahiaIncrementorsDBService {

   private String serviceName;
   private static JahiaIncrementorsDBBaseService theObject = null;



   /***
    * constructor
     * EV    31.10.2000
    * NK    24.12.2000 Client should always call getInstance() method instead
    */
    protected JahiaIncrementorsDBBaseService()
    {
        JahiaConsole.println( "JahiaIncrementorsDBBaseService", "***** Starting the Jahia Incrementors DB Base Service *****" );
    } // end constructor



   /***
    * getInstance
     * EV    31.10.2000
    *
    */
    public static synchronized JahiaIncrementorsDBBaseService getInstance()
    {
        if (theObject == null) {
            theObject = new JahiaIncrementorsDBBaseService();
        }
        return theObject;
    } // end getInstance



   /***
    * autoIncrement
     * EV    02.11.2000
    *
    */
    public int autoIncrement( String tableName )
    throws JahiaException
    {
        try {
            // gets the last id in the incrementors table
            int lastID = getLastID( tableName );

            // adds the new id
            lastID++;
            updateLastID( tableName, lastID );
            return lastID;
        }
        // catches sql error
        catch (JahiaException je)
        {
            JahiaConsole.println( "IncrementorsDBManager", "error in autoIncrement -> BAILING OUT" );
            throw je;
        }
    } // end autoIncrement



   /***
    * getLastID
     * EV    02.11.2000
    *
    */
    private int getLastID( String tableName )
    throws JahiaException
    {
        Connection dbConn = null;
        Statement stmt = null;
        ResultSet rs = null;
        int lastID = 0;
        try {
            int         thereCanBeOnlyOne = 0;
            int         current = 0;
            // composes the query
            String sqlQuery = "";
            sqlQuery += "SELECT jahia_autoids_currentindex FROM jahia_autoids ";
            sqlQuery += "WHERE jahia_autoids_tablename='" + tableName + "'";

            dbConn = ServicesRegistry.getInstance().getDBPoolService().getConnection(35);

            // executes the query
            stmt = dbConn.createStatement();
            rs = ServicesRegistry.getInstance().getDBPoolService().executeQuery( stmt,sqlQuery );

            // parses the results
            while (rs.next()) {
                current = rs.getInt( "jahia_autoids_currentindex") ;
                if (current > thereCanBeOnlyOne) {
                    thereCanBeOnlyOne = current;
                }
            }
            // if no index was found, create a new one
            if (thereCanBeOnlyOne == 0) {
                createNewID( tableName );
            }

            lastID = thereCanBeOnlyOne;

        } catch (SQLException se) {
            String errorMsg = "Error in finding last ID : " + se.getMessage();
            JahiaConsole.println( "IncrementorsDBManager", errorMsg + " -> BAILING OUT" );
            throw new JahiaException(   "Cannot access database incrementors",
                                        errorMsg, JahiaException.DATABASE_ERROR, JahiaException.CRITICAL );
        } finally {
            try {
                ServicesRegistry.getInstance().getDBPoolService().freeConnection(dbConn);
                if ( stmt != null ) stmt.close();
                //if ( rs != null ) rs.close();
            } catch ( SQLException ex ) {
                JahiaException je = new JahiaException(   "Cannot free resources",
                                        "getLastID : cannot free resources",
                                        JahiaException.DATABASE_ERROR, JahiaException.WARNING );
            }
        }
        return lastID;
    } // end getLastID



   /***
    * createNewID
     * EV    02.11.2000
     * EV    04.11.2000  method is now synchrionized
    *
    */
    private synchronized void createNewID( String tableName )
    throws JahiaException
    {
        Connection dbConn = null;
        Statement stmt = null;
        try {
            // composes the query
            String sqlQuery = "";
            sqlQuery += "INSERT INTO jahia_autoids (jahia_autoids_tablename, jahia_autoids_currentindex) ";
            sqlQuery += "VALUES('" + tableName + "',1)";

            dbConn = ServicesRegistry.getInstance().getDBPoolService().getConnection(36);

            // executes the query
            stmt = dbConn.createStatement();
            ServicesRegistry.getInstance().getDBPoolService().executeUpdate( stmt,sqlQuery );

            JahiaConsole.println("JahiaIncrementorsDBBaseService.createNewID","Creating new ID for " + tableName );

        } catch (SQLException se) {
            String errorMsg = "Error in createNewID : " + se.getMessage();
            JahiaConsole.println( "IncrementorsDBManager", errorMsg + " -> BAILING OUT" );
            throw new JahiaException(   "Cannot create new identifiers in the database",
                                        errorMsg, JahiaException.DATABASE_ERROR, JahiaException.CRITICAL );
        } finally {
            try {
                ServicesRegistry.getInstance().getDBPoolService().freeConnection(dbConn);
                if ( stmt != null ) stmt.close();
            } catch ( SQLException ex ) {
                JahiaException je = new JahiaException(   "Cannot free resources",
                                        "createNewID : cannot free resources",
                                        JahiaException.DATABASE_ERROR, JahiaException.WARNING );
            }
        }
    } // end createNewID



   /***
    * updateLastID
     * EV    02.11.2000
     * EV    04.11.2000  method is now synchrionized
    *
    */
    private synchronized void updateLastID( String tableName, int lastID )
    throws JahiaException
    {
        Statement stmt = null;
        Connection dbConn = null;

        try {
            // composes the query
            String sqlQuery = "";
            sqlQuery += "UPDATE jahia_autoids SET ";
            sqlQuery += "jahia_autoids_currentindex=" + lastID + " ";
            sqlQuery += "WHERE jahia_autoids_tablename='" + tableName + "'";

            dbConn = ServicesRegistry.getInstance().getDBPoolService().getConnection(37);

            // executes the query
            stmt = dbConn.createStatement();
              ServicesRegistry.getInstance().getDBPoolService().executeUpdate( stmt,sqlQuery );

        } catch (SQLException se) {
            String errorMsg = "Error in updateLastID : " + se.getMessage();
            JahiaConsole.println( "IncrementorsDBManager", errorMsg );
            JahiaConsole.println( "IncrementorsDBManager", "Cannot update auto-ids -> BAILING OUT" );
            throw new JahiaException(   "Cannot update identifiers in the database",
                                        errorMsg, JahiaException.DATABASE_ERROR, JahiaException.CRITICAL );
        } finally {
            try {

                ServicesRegistry.getInstance().getDBPoolService().freeConnection(dbConn);
                if ( stmt != null ) stmt.close();
            } catch ( SQLException ex ) {
                JahiaException je = new JahiaException(   "Cannot free resources",
                                        "updateLastID : cannot free resources",
                                        JahiaException.DATABASE_ERROR, JahiaException.WARNING );
            }
      }
    } // end updateLastID


   /**
    * Method setName<br>
    * Set the name of the service
    *
    * @param String name
    */
   public void setName(String name){
      this.serviceName = name;
   }


    /***
     * returns a DOM representation of the auto ids table
     * NK    13.08.2001
     *
     */
    public JahiaDOMObject getAutoIdsAsDOM()
    throws JahiaException{

        Connection dbConn = null;
        Statement statement = null;
        ResultSet rs = null;

        JahiaDBDOMObject dom = null;

        try {
            String sqlQuery = "SELECT * FROM jahia_autoids";

            dbConn = getDBConnection();
            statement = dbConn.createStatement();
            if (statement != null) {
                rs = ServicesRegistry.getInstance().getDBPoolService().executeQuery( statement,sqlQuery );
                if (rs != null) {
                    dom = new JahiaDBDOMObject();
                    dom.addTable("jahia_autoids",rs);
                    return dom;
                }
            }
        } catch (SQLException se) {
            String errorMsg = "Error in getAutoIdsAsDOM() : " + se.getMessage();
            JahiaConsole.println( "JahiaIncrementorsDBBaseService", errorMsg);
            throw new JahiaException(   "Cannot load data from the database",
                                        errorMsg, JahiaException.DATABASE_ERROR,
                                        JahiaException.CRITICAL );
        } finally {
            try {
                rs.close();
                rs = null;
            } catch ( Throwable t ) {
            }
            closeDBConnection (dbConn);
            closeStatement (statement);
        }

        return dom;
    }

    //-------------------------------------------------------------------------
    private Connection getDBConnection ()
    {
        return getDBConnection(0);
    }


    //-------------------------------------------------------------------------
    private Connection getDBConnection (int debugInfo)
    {
        Connection dbConn = null;

        try {
            if ( debugInfo != 0 ){
                dbConn = ServicesRegistry.getInstance().getDBPoolService().getConnection (debugInfo);
            } else {
                dbConn = ServicesRegistry.getInstance().getDBPoolService().getConnection ();
            }
        }
        catch (NullPointerException ex) {
            JahiaConsole.println ("JahiaPagesDB", "Null Pointer Exception, DB Pool Service instance might be null!");
        }
        catch (SQLException ex) {
            JahiaConsole.println ("JahiaPagesDB", "SQL Exception: cannot get a connection.");
        }

        return dbConn;
    }


    //-------------------------------------------------------------------------
    private void closeDBConnection (Connection dbConn)
    {
        if (dbConn != null) {
            try {
                ServicesRegistry.getInstance().getDBPoolService().freeConnection (dbConn);
            }
            catch (SQLException sqlEx) {
                // just create an exception without raising it, just to notify it
                // in the logs.
                JahiaException je = new JahiaException ("Cannot free resources",
                        "Cannot free resources", JahiaException.DATABASE_ERROR,
                        JahiaException.WARNING);
            }
            catch (NullPointerException ex) {
                JahiaConsole.println ("JahiaPagesDB", "Null Pointer Exception, DB Pool Service instance might be null!");
            }
        }
    }

    //-------------------------------------------------------------------------
    private void closeStatement (Statement statement)
    {
        // Close the opened statement
        try {
            if (statement!=null) {
                statement.close();
            }
        }
        catch (SQLException sqlEx) {
            // just create an exception without raising it, just to notify it
            // in the logs.
            JahiaException je = new JahiaException ("Cannot close a statement",
                    "Cannot close a statement", JahiaException.DATABASE_ERROR,
                    JahiaException.WARNING);
        }
    }



} // end JahiaIncrementorsDBBaseService