inc/classes/middleware/database/class_DatabaseConnection.php

   1 <?php
   2 /**
   3  * Database selector class
   4  *
   5  * @author              Roland Haeder <webmaster@ship-simu.org>
   6  * @version             0.0
   7  * @copyright   Copyright(c) 2007, 2008 Roland Haeder, this is free software
   8  * @license             GNU GPL 3.0 or any newer version
   9  *
  10  * This program is free software: you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation, either version 3 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22  */
  23 class DatabaseConnection extends BaseMiddleware implements DatabaseConnector, LimitableObject {
  24         // Array for connection data
  25         private $connectData = array();
  26
  27         // The real database layer
  28         private $dbLayer = null;
  29
  30         // An instance of this class
  31         private static $thisInstance = null;
  32
  33         // Private constructor
  34         private final function __construct() {
  35                 // Call parent constructor
  36                 parent::constructor(__CLASS__);
  37
  38                 // Set description
  39                 $this->setPartDescr("Datenbank-Mittelschicht");
  40
  41                 // Create an unique ID
  42                 $this->createUniqueID();
  43
  44                 // Clean up a little
  45                 $this->removeSystemArray();
  46         }
  47
  48         // Create new database connection layer
  49         public final static function createDatabaseConnection (DebugMiddleware $debugInstance, DatabaseFrontendInterface $dbLayer) {
  50                 // Get instance
  51                 $dbInstance = new DatabaseConnection();
  52
  53                 // Set debug output handler
  54                 $dbInstance->setDebugInstance($debugInstance);
  55
  56                 // Set database layer
  57                 $dbInstance->setDatabaseLayer($dbLayer);
  58
  59                 // Set db instance
  60                 self::$thisInstance = $dbInstance;
  61
  62                 // Return instance
  63                 return $dbInstance;
  64         }
  65
  66         // Get an instance of this class
  67         public final static function getInstance () {
  68                 return self::$thisInstance;
  69         }
  70
  71         // Public setter for database connection
  72         public final function setConnectionData ($login, $pass, $dbase, $host) {
  73                 // Transfer connection data
  74                 $this->connectData['login'] = (string) $login;
  75                 $this->connectData['pass']  = (string) $pass;
  76                 $this->connectData['dbase'] = (string) $dbase;
  77                 $this->connectData['host']  = (string) $host;
  78         }
  79
  80         /**
  81          * Save a whole object or parts of it to the database or local file
  82          *
  83          * @param               $object The object we shall save
  84          * @return      void
  85          * @throws      NullPointerException    If $limitInstance is null
  86          * @throws      NoObjectException               If $limitInstance is not an object
  87          * @throws      MissingMethodException  If the required method
  88          *                                                              saveObject() was not found
  89          */
  90         public final function saveObject ($object) {
  91                 // Some sanity checks
  92                 if (is_null($this->dbLayer)) {
  93                         // Is null
  94                         throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
  95                 } elseif (!is_object($this->dbLayer)) {
  96                         // Is not an object
  97                         throw new NoObjectException($this->dbLayer, self::EXCEPTION_IS_NO_OBJECT);
  98                 } elseif (!method_exists($this->dbLayer, 'saveObject')) {
  99                         // Does not have the required instance
 100                         throw new MissingMethodException(array($this->dbLayer, 'saveObject'), self::EXCEPTION_MISSING_METHOD);
 101                 }
 102
 103                 // For now just pipe it through to the database layer
 104                 $this->dbLayer->saveObject($object);
 105         }
 106
 107         /**
 108          * Set a limitation for the saving process. This shall be done before
 109          * saveObject() is called else saveObject() shall save the whole object.
 110          *
 111          * @param               $limitInstance  An instance of ObjectLimits which contains
 112          *                                              elements we shall exclusivly include in
 113          *                                              saving process
 114          * @return      void
 115          * @throws      NullPointerException    If $limitInstance is null
 116          * @throws      NoObjectException               If $limitInstance is not an object
 117          * @throws      MissingMethodException  If the required method
 118          *                                                              limitObject() was not found
 119          */
 120         public final function limitObject (ObjectLimits $limitInstance) {
 121                 // Get real database connection
 122                 $this->dbLayer = $this->getDatabaseInstance();
 123
 124                 // Some sanity checks
 125                 if (is_null($this->dbLayer)) {
 126                         // Is null
 127                         throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
 128                 } elseif (!is_object($this->dbLayer)) {
 129                         // Is not an object
 130                         throw new NoObjectException($object, self::EXCEPTION_IS_NO_OBJECT);
 131                 } elseif (!method_exists($this->dbLayer, 'limitObject')) {
 132                         // Does not have the required instance
 133                         throw new MissingMethodException(array($this->dbLayer, 'limitObject'), self::EXCEPTION_MISSING_METHOD);
 134                 }
 135
 136                 // For now we pipe this through to the real database instance
 137                 $this->dbLayer->limitObject($limitInstance);
 138         }
 139
 140         /**
 141          * Analyses if a unique ID has already been used or not. This method does
 142          * only pass the given ID through to the "real" database layer.
 143          *
 144          * @param               $uniqueID               A unique ID number which shall be checked
 145          *                                              before it will be used
 146          * @param               $inConstructor  If called from a constructor or from
 147          *                                              somewhere else
 148          * @return      $isUnused               true    = The unique ID was not found in the database,
 149          *                                              false = It is already in use by an other object
 150          * @throws      NullPointerException    If $this->dbLayer is null
 151          * @throws      NoObjectException               If $this->dbLayer is not an object
 152          * @throws      MissingMethodException  If the required method
 153          *                                                              isUniqueIdUsed() was not found
 154          */
 155         public final function isUniqueIdUsed ($uniqueID, $inConstructor = false) {
 156                 // Some sanity checks
 157                 if (is_null($this->dbLayer)) {
 158                         // Is null
 159                         throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
 160                 } elseif (!is_object($this->dbLayer)) {
 161                         // Is not an object
 162                         throw new NoObjectException($object, self::EXCEPTION_IS_NO_OBJECT);
 163                 } elseif (!method_exists($this->dbLayer, 'isUniqueIdUsed')) {
 164                         // Does not have the required instance
 165                         throw new MissingMethodException(array($this->dbLayer, 'isUniqueIdUsed'), self::EXCEPTION_MISSING_METHOD);
 166                 }
 167
 168                 // Pass the returning result through
 169                 return $this->dbLayer->isUniqueIdUsed($uniqueID, $inConstructor);
 170         }
 171
 172         /**
 173          * Gets cached data from the database layer and if not found fetch it from
 174          * the database again. This method does not return the header stuff because
 175          * The underlaying database class will return only the requested content.
 176          *
 177          * @param               $idNumber               The ID number which we need for looking up
 178          *                                              the requested data
 179          * @return      $cachedArray    The maybe cached data from the database
 180          * @throws      NullPointerException    If $this->dbLayer is null
 181          * @throws      NoObjectException               If $this->dbLayer is not an object
 182          * @throws      MissingMethodException  If the required method
 183          *                                                              isUniqueIdUsed() was not found
 184          */
 185         public final function getObjectFromCachedData ($idNumber) {
 186                 // Some sanity checks
 187                 if (is_null($this->dbLayer)) {
 188                         // Is null
 189                         throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
 190                 } elseif (!is_object($this->dbLayer)) {
 191                         // Is not an object
 192                         throw new NoObjectException($object, self::EXCEPTION_IS_NO_OBJECT);
 193                 } elseif (!method_exists($this->dbLayer, 'getObjectFromCachedData')) {
 194                         // Does not have the required instance
 195                         throw new MissingMethodException(array($this->dbLayer, 'getObjectFromCachedData'), self::EXCEPTION_MISSING_METHOD);
 196                 }
 197
 198                 // Pass the returning result through
 199                 return $this->dbLayer->getObjectFromCachedData($idNumber);
 200         }
 201
 202         /**
 203          * Setter for the real database layer
 204          * @param               $dbLayer                An instance of the real database layer
 205          * @return      void
 206          */
 207         public final function setDatabaseLayer (DatabaseFrontendInterface $dbLayer) {
 208                 $this->dbLayer = $dbLayer;
 209         }
 210 }
 211
 212 // [EOF]
 213 ?>