* @version 0.3.0
* @copyright Copyright(c) 2007, 2008 Roland Haeder, this is free software
* @license GNU GPL 3.0 or any newer version
* @link http://www.mxchange.org
*
* 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 3 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, see .
*/
class LocalFileDatabase extends BaseDatabaseFrontend implements DatabaseFrontendInterface {
/**
* Save path for "file database"
*/
private $savePath = "";
/**
* The file's extension
*/
private $fileExtension = "serialized";
/**
* The IO handler for file handling which should be FileIOHandler.
*/
private $ioInstance = null;
/**
* The last read file's name
*/
private $lastFile = "";
/**
* The last read file's content including header information
*/
private $lastContents = array();
/**
* The private constructor. Do never instance from outside!
* You need to set a local file path. The class will then validate it.
*
* @return void
*/
private function __construct() {
// Call parent constructor
parent::constructor(__CLASS__);
// Set description
$this->setPartDescr("Dateidatenbankschicht");
// Create unique ID
$this->createUniqueID();
// Clean up a little
$this->removeSystemArray();
}
/**
* Create an object of LocalFileDatabase and set the save path for local files.
* This method also validates the given file path.
*
* @param $savePath The local file path string
* @param $ioInstance The input/output handler. This
* should be FileIOHandler
* @return $dbInstance An instance of LocalFileDatabase
* @throws SavePathIsEmptyException If the given save path is an
* empty string
* @throws SavePathIsNoDirectoryException If the save path is no
* path (e.g. a file)
* @throws SavePathReadProtectedException If the save path is read-
* protected
* @throws SavePathWriteProtectedException If the save path is write-
* protected
*/
public final static function createLocalFileDatabase ($savePath, FileIOHandler $ioInstance) {
// Get an instance
$dbInstance = new LocalFileDatabase();
if (empty($savePath)) {
// Empty string
throw new SavePathIsEmptyException($dbInstance, self::EXCEPTION_UNEXPECTED_EMPTY_STRING);
} elseif (!is_dir($savePath)) {
// Is not a dir
throw new SavePathIsNoDirectoryException($savePath, self::EXCEPTION_INVALID_PATH_NAME);
} elseif (!is_readable($savePath)) {
// Path not readable
throw new SavePathReadProtectedException($savePath, self::EXCEPTION_READ_PROTECED_PATH);
} elseif (!is_writeable($savePath)) {
// Path not writeable
throw new SavePathWriteProtectedException($savePath, self::EXCEPTION_WRITE_PROTECED_PATH);
}
// Debug output
if (defined('DEBUG_DATABASE')) $dbInstance->getDebugInstance()->output(sprintf("[%s:] Es werden lokale Dateien zum Speichern von Objekten verwendet.
\n",
$dbInstance->__toString()
));
// Set save path and IO instance
$dbInstance->setSavePath($savePath);
$dbInstance->setIOInstance($ioInstance);
// Return database instance
return $dbInstance;
}
/**
* Setter for save path
*
* @param $savePath The local save path where we shall put our serialized classes
* @return void
*/
public final function setSavePath ($savePath) {
// Secure string
$savePath = (string) $savePath;
// Debug message
if ((defined('DEBUG_DATABASE')) || (defined('DEBUG_ALL'))) $this->getDebugInstance()->output(sprintf("[%s:] Lokaler Speicherpfad %s wird verwendet.
\n",
$this->__toString(),
$savePath
));
// Set save path
$this->savePath = $savePath;
}
/**
* Getter for save path
*
* @return $savePath The local save path where we shall put our serialized classes
*/
public final function getSavePath () {
return $this->savePath;
}
/**
* Getter for file extension
*
* @return $fileExtension The file extension for all file names
*/
public final function getFileExtension () {
return $this->fileExtension;
}
/**
* Saves a given object to the local file system by serializing and
* transparently compressing it
*
* @param $object The object we shall save to the local file system
* @return void
* @throws NullPointerException If the object instance is null
* @throws NoObjectException If the parameter $object is not
* an object
*/
public final function saveObject ($object) {
// Some tests on the parameter...
if (is_null($object)) {
// Is null, throw exception
throw new NullPointerException($object, self::EXCEPTION_IS_NULL_POINTER);
} elseif (!is_object($object)) {
// Is not an object, throw exception
throw new NoObjectException($object, self::EXCEPTION_IS_NO_OBJECT);
} elseif (!method_exists($object, '__toString')) {
// A highly required method was not found... :-(
throw new MissingMethodException(array($object, '__toString'), self::EXCEPTION_MISSING_METHOD);
}
// Debug message
if ((defined('DEBUG_DATABASE')) || (defined('DEBUG_ALL'))) $this->getDebugInstance()->output(sprintf("[%s:] Das Objekt %s soll in eine lokale Datei gespeichert werden.
\n",
$this->__toString(),
$object->__toString()
));
// Get a string containing the serialized object. We cannot exchange
// $this and $object here because $object does not need to worry
// about it's limitations... ;-)
$serialized = $this->serializeObject($object);
// Debug message
if ((defined('DEBUG_DATABASE')) || (defined('DEBUG_ALL'))) $this->getDebugInstance()->output(sprintf("[%s:] Das Objekt %s ist nach der Serialisierung %s Byte gross.
\n",
$this->__toString(),
$object->__toString(),
strlen($serialized)
));
// Get a path name plus file name and append the extension
$fqfn = $this->getSavePath() . $object->getPathFileNameFromObject() . "." . $this->getFileExtension();
// Save the file to disc we don't care here if the path is there,
// this must be done in later methods.
$this->getIOInstance()->saveFile($fqfn, array($this->getCompressorChannel()->getCompressorExtension(), $serialized));
}
/**
* Get a serialized string from the given object
*
* @param $object The object we want to serialize and transparently
* compress
* @return $serialized A string containing the serialzed/compressed object
* @see ObjectLimits An object holding limition information
* @see SerializationContainer A special container class for e.g.
* attributes from limited objects
*/
private function serializeObject ($object) {
// If there is no limiter instance we serialize the whole object
// otherwise only in the limiter object (ObjectLimits) specified
// attributes summarized in a special container class
if ($this->getLimitInstance() === null) {
// Serialize the whole object. This tribble call is the reason
// why we need a fall-back implementation in CompressorChannel
// of the methods compressStream() and decompressStream().
$serialized = $this->getCompressorChannel()->getCompressor()->compressStream(serialize($object));
} else {
// Serialize only given attributes in a special container
$container = SerializationContainer::createSerializationContainer($this->getLimitInstance(), $object);
// Serialize the container
$serialized = $this->getCompressorChannel()->getCompressor()->compressStream(serialize($container));
}
// Return the serialized object string
return $serialized;
}
/**
* Analyses if a unique ID has already been used or not by search in the
* local database folder.
*
* @param $uniqueID A unique ID number which shall be checked
* before it will be used
* @param $inConstructor If we got called in a de/con-structor or
* from somewhere else
* @return $isUnused true = The unique ID was not found in the database,
* false = It is already in use by an other object
* @throws NoArrayCreatedException If explode() fails to create an array
* @throws InvalidArrayCountException If the array contains less or
* more than two elements
*/
public function isUniqueIdUsed ($uniqueID, $inConstructor = false) {
// Currently not used... ;-)
$isUsed = false;
// Split the unique ID up in path and file name
$pathFile = explode("@", $uniqueID);
// Are there two elements? Index 0 is the path, 1 the file name + global extension
if (!is_array($pathFile)) {
// No array found
if ($inConstructor) {
return false;
} else {
throw new NoArrayCreatedException(array($this, "pathFile"), self::EXCEPTION_ARRAY_EXPECTED);
}
} elseif (count($pathFile) != 2) {
// Invalid ID returned!
if ($inConstructor) {
return false;
} else {
throw new InvalidArrayCountException(array($this, "pathFile", count($pathFile), 2), self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
}
}
// Create full path name
$pathName = $this->getSavePath() . $pathFile[0];
// Check if the file is there with a file handler
if ($inConstructor) {
// No exceptions in constructors and destructors!
$dirInstance = FrameworkDirectoryPointer::createFrameworkDirectoryPointer($pathName, true);
// Has an object being created?
if (!is_object($dirInstance)) return false;
} else {
// Outside a constructor
try {
$dirInstance = FrameworkDirectoryPointer::createFrameworkDirectoryPointer($pathName);
} catch (PathIsNoDirectoryException $e) {
// Okay, path not found
return false;
}
}
// Initialize the search loop
$isValid = false;
while ($dataFile = $dirInstance->readDirectoryExcept(array(".", ".."))) {
// Generate FQFN for testing
$fqfn = sprintf("%s/%s", $pathName, $dataFile);
$this->setLastFile($fqfn);
// Get instance for file handler
$inputHandler = $this->getIOInstance();
// Try to read from it. This makes it sure that the file is
// readable and a valid database file
$this->setLastFileContents($inputHandler->loadFileContents($fqfn));
// Extract filename (= unique ID) from it
$ID = substr(basename($fqfn), 0, -(strlen($this->getFileExtension()) + 1));
// Is this the required unique ID?
if ($ID == $pathFile[1]) {
// Okay, already in use!
$isUsed = true;
}
}
// Close the directory handler
$dirInstance->closeDirectory();
// Now the same for the file...
return $isUsed;
}
/**
* Getter for the file IO instance
*
*�@return $ioInstance An instance for IO operations
* @see FileIOHandler The concrete handler for IO operations
*/
public final function getIOInstance () {
return $this->ioInstance;
}
/**
* Setter for the file IO instance
*
* @param $ioInstance An instance for IO operations (should be
* FileIOHandler)
* @return void
*/
public final function setIOInstance (FileIOHandler $ioInstance) {
$this->ioInstance = $ioInstance;
}
/**
* Setter for the last read file
*
* @param $fqfn The FQFN of the last read file
* @return void
*/
private function setLastFile ($fqfn) {
// Cast string
$fqfn = (string) $fqfn;
$this->lastFile = $fqfn;
}
/**
* Getter for last read file
*
* @return $lastFile The last read file's name with full path
*/
public final function getLastFile () {
return $this->lastFile;
}
/**
* Setter for contents of the last read file
*
* @param $contents An array with header and data elements
* @return void
*/
private function setLastFileContents ($contents) {
// Cast array
$contents = (array) $contents;
$this->lastContents = $contents;
}
/**
* Getter for last read file's content as an array
*
* @return $lastContent The array with elements 'header' and 'data'.
*/
public final function getLastContents () {
return $this->lastContents;
}
/**
* Get cached (last fetched) data from the local file database
*
* @param $uniqueID The ID number for looking up the data
* @return $object The restored object from the maybe compressed
* serialized data
* @throws MismatchingCompressorsException If the compressor from
* the loaded file
* mismatches with the
* current used one.
* @throws NullPointerException If the restored object
* is null
* @throws NoObjectException If the restored "object"
* is not an object instance
* @throws MissingMethodException If the required method
* toString() is missing
*/
public final function getObjectFromCachedData ($uniqueID) {
// Get instance for file handler
$inputHandler = $this->getIOInstance();
// Get last file's name and contents
$fqfn = $this->repairFQFN($this->getLastFile(), $uniqueID);
$contents = $this->repairContents($this->getLastContents(), $fqfn);
// Let's decompress it. First we need the instance
$compressInstance = $this->getCompressorChannel();
// Is the compressor's extension the same as the one from the data?
if ($compressInstance->getCompressorExtension() != $contents['header'][0]) {
/**
* @todo For now we abort here but later we need to make this a little more dynamic.
*/
throw new MismatchingCompressorsException(array($this, $contents['header'][0], $fqfn, $compressInstance->getCompressorExtension()), self::EXCEPTION_MISMATCHING_COMPRESSORS);
}
// Decompress the data now
$serialized = $compressInstance->getCompressor()->decompressStream($contents['data']);
// And unserialize it...
$object = unserialize($serialized);
// This must become a valid object, so let's check it...
if (is_null($object)) {
// Is null, throw exception
throw new NullPointerException($object, self::EXCEPTION_IS_NULL_POINTER);
} elseif (!is_object($object)) {
// Is not an object, throw exception
throw new NoObjectException($object, self::EXCEPTION_IS_NO_OBJECT);
} elseif (!method_exists($object, '__toString')) {
// A highly required method was not found... :-(
throw new MissingMethodException(array($object, '__toString'), self::EXCEPTION_MISSING_METHOD);
}
// And return the object
return $object;
}
/**
* Private method for re-gathering (repairing) the FQFN
*
* @param $fqfn The current FQFN we shall validate
* @param $uniqueID The unique ID number
* @return $fqfn The repaired FQFN when it is empty
* @throws NoArrayCreatedException If explode() has not
* created an array
* @throws InvalidArrayCountException If the array count is not
* as the expected
*/
private function repairFQFN ($fqfn, $uniqueID) {
// Cast both strings
$fqfn = (string) $fqfn;
$uniqueID = (string) $uniqueID;
// Is there pre-cached data available?
if (empty($fqfn)) {
// Split the unique ID up in path and file name
$pathFile = explode("@", $uniqueID);
// Are there two elements? Index 0 is the path, 1 the file name + global extension
if (!is_array($pathFile)) {
// No array found
throw new NoArrayCreatedException(array($this, "pathFile"), self::EXCEPTION_ARRAY_EXPECTED);
} elseif (count($pathFile) != 2) {
// Invalid ID returned!
throw new InvalidArrayCountException(array($this, "pathFile", count($pathFile), 2), self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
}
// Create full path name
$pathName = $this->getSavePath() . $pathFile[0];
// Nothing cached, so let's create a FQFN first
$fqfn = sprintf("%s/%s.%s", $pathName, $pathFile[1], $this->getFileExtension());
$this->setLastFile($fqfn);
}
// Return repaired FQFN
return $fqfn;
}
/**
* Private method for re-gathering the contents of a given file
*
* @param $contents The (maybe) already cached contents as an array
* @param $fqfn The current FQFN we shall validate
* @return $contents The repaired contents from the given file
*/
private function repairContents ($contents, $fqfn) {
// Is there some content and header (2 indexes) in?
if ((!is_array($contents)) || (count($contents) != 2) || (!isset($contents['header'])) || (!isset($contents['data']))) {
// No content found so load the file again
$contents = $inputHandler->loadFileContents($fqfn);
// And remember all data for later usage
$this->setLastContents($contents);
}
// Return the repaired contents
return $contents;
}
/* DUMMY */ public final function loadObject () {}
}
// [EOF]
?>