Addressbook/src/org/mxchange/addressbook/database/backend/mysql/MySqlDatabaseBackend.java

   1 /*
   2  * Copyright (C) 2015 Roland Haeder
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 package org.mxchange.addressbook.database.backend.mysql;
  18
  19 import java.io.IOException;
  20 import java.sql.Connection;
  21 import java.sql.DriverManager;
  22 import java.sql.PreparedStatement;
  23 import java.sql.ResultSet;
  24 import java.sql.SQLException;
  25 import java.text.MessageFormat;
  26 import java.util.Iterator;
  27 import org.mxchange.addressbook.contact.Contact;
  28 import org.mxchange.addressbook.database.backend.BaseDatabaseBackend;
  29 import org.mxchange.addressbook.database.backend.DatabaseBackend;
  30 import org.mxchange.addressbook.database.storage.Storeable;
  31 import org.mxchange.addressbook.exceptions.BadTokenException;
  32 import org.mxchange.addressbook.exceptions.UnsupportedDatabaseDriverException;
  33
  34 /**
  35  * A backend class for MySQL connections
  36  *
  37  * @author Roland Haeder
  38  */
  39 public class MySqlDatabaseBackend extends BaseDatabaseBackend implements DatabaseBackend {
  40         /**
  41          * An instance of a datbase connection
  42          */
  43         private static Connection connection;
  44
  45         /**
  46          * Prepared statement for full row count
  47          */
  48         private PreparedStatement totalRowCount;
  49
  50         /**
  51          * Constructor with table name
  52          *
  53          * @param tableName Table to access
  54          * @throws org.mxchange.addressbook.exceptions.UnsupportedDatabaseDriverException
  55          */
  56         public MySqlDatabaseBackend (final String tableName) throws UnsupportedDatabaseDriverException {
  57                 // Validate driver
  58                 this.validateDriver("mysql"); //NOI18N
  59
  60                 // Now that the driver is there, set the table name
  61                 this.setTableName(tableName);
  62         }
  63
  64         @Override
  65         public void connectToDatabase () throws SQLException {
  66                 // Trace message
  67                 this.getLogger().trace("CALLED!"); //NOI18N
  68
  69                 // Is the connection already there?
  70                 if (MySqlDatabaseBackend.connection instanceof Connection) {
  71                         // Already connected
  72                         this.getLogger().debug("Connection is already established."); //NOI18N
  73
  74                         // No need to connect
  75                         return;
  76                 }
  77
  78                 // Generate connection string
  79                 String connect = String.format("jdbc:mysql://%s/%s", //NOI18N
  80                                 this.getProperty("database.mysql.host"), //NOI18N
  81                                 this.getProperty("database.mysql.dbname") //NOI18N
  82                 );
  83
  84                 // Debug message
  85                 this.getLogger().debug(MessageFormat.format("Attempting to connect to {0} ...", connect)); //NOI18N
  86
  87                 // Now get a connection instance back
  88                 MySqlDatabaseBackend.connection = DriverManager.getConnection(
  89                                 connect,
  90                                 this.getProperty("database.mysql.login"), //NOI18N
  91                                 this.getProperty("database.mysql.password") //NOI18N
  92                 );
  93
  94                 // Is the connection really up?
  95                 if (MySqlDatabaseBackend.connection.isClosed()) {
  96                         // Connection is closed again
  97                         throw new SQLException("Connection is closed."); //NOI18N
  98                 }
  99
 100                 // Debug message
 101                 this.getLogger().debug("Connection is up, preparing some statements ..."); //NOI18N
 102
 103                 // Here, the connection is established, so prepare some statements
 104                 this.totalRowCount = MySqlDatabaseBackend.connection.prepareStatement(String.format("SELECT COUNT(`id`) AS `cnt` FROM `%s` LIMIT 1", this.getTableName())); //NOI18N
 105
 106                 // Trace message
 107                 this.getLogger().trace("EXIT!"); //NOI18N
 108         }
 109
 110         @Override
 111         @Deprecated
 112         public Iterator<Contact> contactIterator () throws BadTokenException {
 113                 throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
 114         }
 115
 116         @Override
 117         public void doShutdown () {
 118                 // This should not happen:
 119                 assert(MySqlDatabaseBackend.connection instanceof Connection) : MessageFormat.format("connection is not valid: {0}", MySqlDatabaseBackend.connection); //NOI18N
 120
 121                 try {
 122                         // Close down database connection
 123                         MySqlDatabaseBackend.connection.close();
 124                 } catch (final SQLException ex) {
 125                         // Something happened during close()
 126                         this.abortProgramWithException(ex);
 127                 }
 128         }
 129
 130         @Override
 131         public int getTotalCount () throws SQLException {
 132                 // Trace message
 133                 this.getLogger().trace(MessageFormat.format("tableName={0} - CALLED!", this.getTableName())); //NOI18N
 134
 135                 // Nothing counted by default
 136                 int count = 0;
 137
 138                 // Prepared statements are cool ...
 139                 if (this.totalRowCount.execute()) {
 140                         // Did fully work, so get result set
 141                         ResultSet set = this.totalRowCount.getResultSet();
 142
 143                         // First rewind it
 144                         assert(set.last()) : ": last() failed"; //NOI18N
 145
 146                         // Get integer from 'cnt' alias (see statement)
 147                         count = set.getInt("cnt"); //NOI18N
 148
 149                         // Debug message
 150                         this.getLogger().debug(MessageFormat.format("count={0}", count)); //NOI18N
 151
 152                         // Go back to beginning
 153                         set.beforeFirst();
 154                 } else {
 155                         // Empty result
 156                         this.getLogger().warn(MessageFormat.format("COUNT() query didn't return any result on table {0}.", this.getTableName())); //NOI18N
 157                 }
 158
 159                 // Trace message
 160                 this.getLogger().trace(MessageFormat.format("count={0} - EXIT!", count)); //NOI18N
 161
 162                 // Return result
 163                 return count;
 164         }
 165
 166         /**
 167          * Checks whether at least one row is found with given boolean value.
 168          *
 169          * @param columnName Column to check for boolean value
 170          * @param bool Boolean value to check
 171          * @return Whether boolean value is found and returns at least one row
 172          */
 173         @Override
 174         public boolean isRowFound (final String columnName, final boolean bool) throws SQLException {
 175                 // Is at least one entry found?
 176                 if (this.getTotalCount() == 0) {
 177                         // No entry found at all
 178                         return false;
 179                 }
 180                 throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
 181         }
 182
 183         @Override
 184         public long length () {
 185                 throw new UnsupportedOperationException("Not implemented for this backend."); //NOI18N
 186         }
 187
 188         @Override
 189         public void rewind () {
 190                 throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
 191         }
 192
 193         @Override
 194         public void store (final Storeable object) throws IOException {
 195                 throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
 196         }
 197 }