source: greenstone3/trunk/src/java/org/greenstone/gsdl3/sql/derby/DerbyDBWrapper.java@ 16883

package org.greenstone.gsdl3.sql.derby;

import  org.greenstone.gsdl3.sql.*;


import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.Statement;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;


import org.greenstone.gsdl3.util.DBInfo;

import org.apache.log4j.*;

public class DerbyDBWrapper implements MetadataDBWrapper{
    protected SQLServer sqlServer = null;
    protected SQLStatements sqlState = null;
    protected Connection connection = null; 
    protected Statement statement = null;
    protected static Logger logger = Logger.getLogger(org.greenstone.gsdl3.sql.derby.DerbyDBWrapper.class.getName());


    public DBInfo getInfo(String id){
    if(sqlState == null) return null;
        String dbInfoState = sqlState.getDBInfoStatement(id);
        ArrayList result = executeQuery(dbInfoState);
    if (result.size() == 0) return null;
    DBInfo info = new DBInfo();
    for(int i=0;  i<result.size();i++){
        HashMap arow = (HashMap)result.get(i);
        Iterator ite = arow.keySet().iterator();
        while(ite.hasNext()){
        String key = (String)ite.next();
        Object value = arow.get(key);
        //logger.info(key + "=>" +value);
        if (value == null || value.equals("")) continue;
        info.addInfo(key.toLowerCase(),sqlState.undoDBSafe(value));
        }
    }

    return info;
    }

    public void setSQLServer(SQLServer server){
    sqlServer = server;
    }

    public void setSQLStatements(SQLStatements state){
    sqlState = state;
    }

    public boolean openConnection(String databasepath){
    connection = sqlServer.connect(databasepath);
    
    if (connection == null) return false;

    try{
        connection.setAutoCommit(false);    
        statement = connection.createStatement();
    }
    catch(SQLException sqle){
        logger.debug("Database Error occured when creating a statement object",sqle);
        return false;
    }
    return true;
    }

    public boolean openAndCreateConnection(String databasepath){
        connection = sqlServer.connectAndCreate(databasepath);

        if (connection == null) {
            logger.error("sql connection is null. database path="+databasepath);
            return false;
        }

        try{
            connection.setAutoCommit(true); 
            //by passing the two arguments, the ResultSet returned from executeQuery is updatable
            statement = connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
            if (statement == null) {
                logger.error("statement is null");
                return false;
            }

        }
        catch(SQLException sqle){
            logger.debug("Database Error occured when creating a statement object",sqle);
            return false;
        }
        return true;
    }

    public synchronized ArrayList executeQuery(String query_statement){
    //the database hasn't been correct yet
        ArrayList results = new ArrayList();
    try{    
        
        if (statement == null){
            logger.info("the database hasn't been correct yet");
            return new ArrayList();
        }
    
        ResultSet rs = statement.executeQuery(query_statement);
        ResultSetMetaData rsmd = rs.getMetaData();
        int numOfColumns = rsmd.getColumnCount();
        while(rs.next()){
           HashMap arow = new HashMap();
           for(int i = 1; i <= numOfColumns ; i++){
               arow.put(rsmd.getColumnName(i).toLowerCase(), rs.getObject(i));
           }
           results.add(arow);  
       }
    }
    catch(SQLException sqle){
        logger.debug("Database Error occured when executeQuery " + query_statement,sqle);
        return results;
    }
    catch(Exception e){         
        logger.debug(e);
        return null;
    }
    return results;
    }
    /**
     * Same as executeQuery except the return type is ResultSet
     * @param stat
     * @return ResultSet of querying the statement 'stat'
     */
    public synchronized ResultSet queryResultSet(String stat){
        ResultSet rs = null;
        try{            
            if (statement == null){
                logger.info("Null sql statement provided.");
                return null;
            }
            logger.debug(stat);
            rs = statement.executeQuery(stat);
            
            logger.info("sql stat="+stat+ " result="+rs);
        }
        catch(SQLException sqle){
            logger.info("Database Error occured when execute query " + stat, sqle);
            return null;
        }
        catch(Exception e){         
            logger.info("Exception="+e);
            return null;
        }
        logger.debug(" result="+rs);
        return rs;
    }
    /**
     * Used by create (table)
     */
    public synchronized boolean execute(String stat) {
        boolean rs;
        try{            
            if (statement == null){
                logger.info("statement is null.");
                return false;
            }

            rs = statement.execute(stat);
//          connection.commit();
        }
        catch(SQLException sqle){           
            logger.debug("Database Error occured when execute query " + stat, sqle);
            return false;
        }
        catch(Exception e){         
            logger.debug(e);
            return false;
        }
        return rs;
    }
    /**
     * Used by insert, update, and delete
     */
    public synchronized boolean executeUpdate(String stat) {
        int rs;
        try{            
            if (statement == null){
                logger.info("statement is null.");
                return false;
            }
            
            //either the row count of INSERT, UPDATE OR DELETE statement, or 0 if the statement returns nothing
            rs = statement.executeUpdate(stat);
//          connection.commit();
            logger.info("sql stat="+stat+ " result="+rs);
        }
        catch(SQLException sqle){           
            logger.info("Database Error occured when execute query " + stat, sqle);
            return false;
        }
        catch(Exception e){         
            logger.info("Exception="+e);
            return false;
        }
        logger.info(" result="+rs);
        return (rs==-1)? false : true;
    }
    /**
     * Used by checking the existence of table
     * Same as the method 'execute' except throws SQLException
     */
    public void check4Table(String stat) throws SQLException {
        statement.executeQuery(stat);
    }

    public void closeConnection(String databasepath){
    sqlServer.disconnect(databasepath);
    }
  
 }