php 抽象类适配器设计模式

以Kohana Cache设计为例

1、抽象类：E:\html\tproject\framework\modules\cache\classes\Cache.php

<?php defined('SYSPATH') or die('No direct script access.');

abstract class Cache extends Kohana_Cache {}

2、抽象类：E:\html\tproject\framework\modules\cache\classes\Kohana\Cache.php

<?php defined('SYSPATH') or die('No direct script access.');
/**
 * Kohana Cache provides a common interface to a variety of caching engines. Tags are
 * supported where available natively to the cache system. Kohana Cache supports multiple
 * instances of cache engines through a grouped singleton pattern.
 *
 * ### Supported cache engines
 *
 * *  [APC](http://php.net/manual/en/book.apc.php)
 * *  [eAccelerator](http://eaccelerator.net/)
 * *  File
 * *  [Memcache](http://memcached.org/)
 * *  [Memcached-tags](http://code.google.com/p/memcached-tags/)
 * *  [SQLite](http://www.sqlite.org/)
 * *  [Xcache](http://xcache.lighttpd.net/)
 *
 * ### Introduction to caching
 *
 * Caching should be implemented with consideration. Generally, caching the result of resources
 * is faster than reprocessing them. Choosing what, how and when to cache is vital. PHP APC is
 * presently one of the fastest caching systems available, closely followed by Memcache. SQLite
 * and File caching are two of the slowest cache methods, however usually faster than reprocessing
 * a complex set of instructions.
 *
 * Caching engines that use memory are considerably faster than the file based alternatives. But
 * memory is limited whereas disk space is plentiful. If caching large datasets it is best to use
 * file caching.
 *
 * ### Configuration settings
 *
 * Kohana Cache uses configuration groups to create cache instances. A configuration group can
 * use any supported driver, with successive groups using the same driver type if required.
 *
 * #### Configuration example
 *
 * Below is an example of a _memcache_ server configuration.
 *
 *     return array(
 *          'memcache' => array(                           // Name of group
 *                  'driver'         => 'memcache',        // using Memcache driver
 *                  'servers'        => array(             // Available server definitions
 *                         array(
 *                              'host'       => 'localhost',
 *                              'port'       => 11211,
 *                              'persistent' => FALSE
 *                         )
 *                  ),
 *                  'compression'    => FALSE,             // Use compression?
 *           ),
 *     )
 *
 * In cases where only one cache group is required, set `Cache::$default` (in your bootstrap,
 * or by extending `Kohana_Cache` class) to the name of the group, and use:
 *
 *     $cache = Cache::instance(); // instead of Cache::instance('memcache')
 *
 * It will return the cache instance of the group it has been set in `Cache::$default`.
 *
 * #### General cache group configuration settings
 *
 * Below are the settings available to all types of cache driver.
 *
 * Name           | Required | Description
 * -------------- | -------- | ---------------------------------------------------------------
 * driver         | __YES__  | (_string_) The driver type to use
 *
 * Details of the settings specific to each driver are available within the drivers documentation.
 *
 * ### System requirements
 *
 * *  Kohana 3.0.x
 * *  PHP 5.2.4 or greater
 *
 * @package    Kohana/Cache
 * @category   Base
 * @version    2.0
 * @author     Kohana Team
 * @copyright  (c) 2009-2012 Kohana Team
 * @license    http://kohanaphp.com/license
 */
abstract class Kohana_Cache {

	const DEFAULT_EXPIRE = 3600;

	/**
	 * @var   string     default driver to use
	 */
	public static $default = 'file';

	/**
	 * @var   Kohana_Cache instances
	 */
	public static $instances = array();

	/**
	 * Creates a singleton of a Kohana Cache group. If no group is supplied
	 * the __default__ cache group is used.
	 *
	 *     // Create an instance of the default group
	 *     $default_group = Cache::instance();
	 *
	 *     // Create an instance of a group
	 *     $foo_group = Cache::instance('foo');
	 *
	 *     // Access an instantiated group directly
	 *     $foo_group = Cache::$instances['default'];
	 *
	 * @param   string  $group  the name of the cache group to use [Optional]
	 * @return  Cache
	 * @throws  Cache_Exception
	 */
	public static function instance($group = NULL)
	{
		// If there is no group supplied
		if ($group === NULL)
		{
			// Use the default setting
			$group = Cache::$default;
		}

		if (isset(Cache::$instances[$group]))
		{
			// Return the current group if initiated already
			return Cache::$instances[$group];
		}

		$config = Kohana::$config->load('cache');

		if ( ! $config->offsetExists($group))
		{
			throw new Cache_Exception(
				'Failed to load Kohana Cache group: :group',
				array(':group' => $group)
			);
		}

		$config = $config->get($group);

		// Create a new cache type instance
		$cache_class = 'Cache_'.ucfirst($config['driver']);
		Cache::$instances[$group] = new $cache_class($config);

		// Return the instance
		return Cache::$instances[$group];
	}

	/**
	 * @var  Config
	 */
	protected $_config = array();

	/**
	 * Ensures singleton pattern is observed, loads the default expiry
	 *
	 * @param  array  $config  configuration
	 */
	protected function __construct(array $config)
	{
		$this->config($config);
	}

	/**
	 * Getter and setter for the configuration. If no argument provided, the
	 * current configuration is returned. Otherwise the configuration is set
	 * to this class.
	 *
	 *     // Overwrite all configuration
	 *     $cache->config(array('driver' => 'memcache', '...'));
	 *
	 *     // Set a new configuration setting
	 *     $cache->config('servers', array(
	 *          'foo' => 'bar',
	 *          '...'
	 *          ));
	 *
	 *     // Get a configuration setting
	 *     $servers = $cache->config('servers);
	 *
	 * @param   mixed    key to set to array, either array or config path
	 * @param   mixed    value to associate with key
	 * @return  mixed
	 */
	public function config($key = NULL, $value = NULL)
	{
		if ($key === NULL)
			return $this->_config;

		if (is_array($key))
		{
			$this->_config = $key;
		}
		else
		{
			if ($value === NULL)
				return Arr::get($this->_config, $key);

			$this->_config[$key] = $value;
		}

		return $this;
	}

	/**
	 * Overload the __clone() method to prevent cloning
	 *
	 * @return  void
	 * @throws  Cache_Exception
	 */
	final public function __clone()
	{
		throw new Cache_Exception('Cloning of Kohana_Cache objects is forbidden');
	}

	/**
	 * Retrieve a cached value entry by id.
	 *
	 *     // Retrieve cache entry from default group
	 *     $data = Cache::instance()->get('foo');
	 *
	 *     // Retrieve cache entry from default group and return 'bar' if miss
	 *     $data = Cache::instance()->get('foo', 'bar');
	 *
	 *     // Retrieve cache entry from memcache group
	 *     $data = Cache::instance('memcache')->get('foo');
	 *
	 * @param   string  $id       id of cache to entry
	 * @param   string  $default  default value to return if cache miss
	 * @return  mixed
	 * @throws  Cache_Exception
	 */
	abstract public function get($id, $default = NULL);

	/**
	 * Set a value to cache with id and lifetime
	 *
	 *     $data = 'bar';
	 *
	 *     // Set 'bar' to 'foo' in default group, using default expiry
	 *     Cache::instance()->set('foo', $data);
	 *
	 *     // Set 'bar' to 'foo' in default group for 30 seconds
	 *     Cache::instance()->set('foo', $data, 30);
	 *
	 *     // Set 'bar' to 'foo' in memcache group for 10 minutes
	 *     if (Cache::instance('memcache')->set('foo', $data, 600))
	 *     {
	 *          // Cache was set successfully
	 *          return
	 *     }
	 *
	 * @param   string   $id        id of cache entry
	 * @param   string   $data      data to set to cache
	 * @param   integer  $lifetime  lifetime in seconds
	 * @return  boolean
	 */
	abstract public function set($id, $data, $lifetime = 3600);

	/**
	 * Delete a cache entry based on id
	 *
	 *     // Delete 'foo' entry from the default group
	 *     Cache::instance()->delete('foo');
	 *
	 *     // Delete 'foo' entry from the memcache group
	 *     Cache::instance('memcache')->delete('foo')
	 *
	 * @param   string  $id  id to remove from cache
	 * @return  boolean
	 */
	abstract public function delete($id);

	/**
	 * Delete all cache entries.
	 *
	 * Beware of using this method when
	 * using shared memory cache systems, as it will wipe every
	 * entry within the system for all clients.
	 *
	 *     // Delete all cache entries in the default group
	 *     Cache::instance()->delete_all();
	 *
	 *     // Delete all cache entries in the memcache group
	 *     Cache::instance('memcache')->delete_all();
	 *
	 * @return  boolean
	 */
	abstract public function delete_all();

	/**
	 * Replaces troublesome characters with underscores.
	 *
	 *     // Sanitize a cache id
	 *     $id = $this->_sanitize_id($id);
	 *
	 * @param   string  $id  id of cache to sanitize
	 * @return  string
	 */
	protected function _sanitize_id($id)
	{
		// Change slashes and spaces to underscores
		return str_replace(array('/', '\\', ' '), '_', $id);
	}
}
// End Kohana_Cache

　

3、缓存方式File、Memcache、Apc、Wincache实现类

3.1、E:\html\tproject\framework\modules\cache\classes\Cache\File.php

<?php defined('SYSPATH') or die('No direct script access.');

class Cache_File extends Kohana_Cache_File {}

3.2、E:\html\tproject\framework\modules\cache\classes\Kohana\Cache\File.php

<?php defined('SYSPATH') or die('No direct script access.');
/**
 * [Kohana Cache](api/Kohana_Cache) File driver. Provides a file based
 * driver for the Kohana Cache library. This is one of the slowest
 * caching methods.
 *
 * ### Configuration example
 *
 * Below is an example of a _file_ server configuration.
 *
 *     return array(
 *          'file'   => array(                          // File driver group
 *                  'driver'         => 'file',         // using File driver
 *                  'cache_dir'     => APPPATH.'cache/.kohana_cache', // Cache location
 *           ),
 *     )
 *
 * In cases where only one cache group is required, if the group is named `default` there is
 * no need to pass the group name when instantiating a cache instance.
 *
 * #### General cache group configuration settings
 *
 * Below are the settings available to all types of cache driver.
 *
 * Name           | Required | Description
 * -------------- | -------- | ---------------------------------------------------------------
 * driver         | __YES__  | (_string_) The driver type to use
 * cache_dir      | __NO__   | (_string_) The cache directory to use for this cache instance
 *
 * ### System requirements
 *
 * *  Kohana 3.0.x
 * *  PHP 5.2.4 or greater
 *
 * @package    Kohana/Cache
 * @category   Base
 * @author     Kohana Team
 * @copyright  (c) 2009-2012 Kohana Team
 * @license    http://kohanaphp.com/license
 */
class Kohana_Cache_File extends Cache implements Cache_GarbageCollect {

	/**
	 * Creates a hashed filename based on the string. This is used
	 * to create shorter unique IDs for each cache filename.
	 *
	 *     // Create the cache filename
	 *     $filename = Cache_File::filename($this->_sanitize_id($id));
	 *
	 * @param   string  $string  string to hash into filename
	 * @return  string
	 */
	protected static function filename($string)
	{
		return sha1($string).'.cache';
	}

	/**
	 * @var  string   the caching directory
	 */
	protected $_cache_dir;

	/**
	 * Constructs the file cache driver. This method cannot be invoked externally. The file cache driver must
	 * be instantiated using the `Cache::instance()` method.
	 *
	 * @param   array  $config  config
	 * @throws  Cache_Exception
	 */
	protected function __construct(array $config)
	{
		// Setup parent
		parent::__construct($config);

		try
		{
			$directory = Arr::get($this->_config, 'cache_dir', Kohana::$cache_dir);
			$this->_cache_dir = new SplFileInfo($directory);
		}
		// PHP < 5.3 exception handle
		catch (ErrorException $e)
		{
			$this->_cache_dir = $this->_make_directory($directory, 0777, TRUE);
		}
		// PHP >= 5.3 exception handle
		catch (UnexpectedValueException $e)
		{
			$this->_cache_dir = $this->_make_directory($directory, 0777, TRUE);
		}

		// If the defined directory is a file, get outta here
		if ($this->_cache_dir->isFile())
		{
			throw new Cache_Exception('Unable to create cache directory as a file already exists : :resource', array(':resource' => $this->_cache_dir->getRealPath()));
		}

		// Check the read status of the directory
		if ( ! $this->_cache_dir->isReadable())
		{
			throw new Cache_Exception('Unable to read from the cache directory :resource', array(':resource' => $this->_cache_dir->getRealPath()));
		}

		// Check the write status of the directory
		if ( ! $this->_cache_dir->isWritable())
		{
			throw new Cache_Exception('Unable to write to the cache directory :resource', array(':resource' => $this->_cache_dir->getRealPath()));
		}
	}

	/**
	 * Retrieve a cached value entry by id.
	 *
	 *     // Retrieve cache entry from file group
	 *     $data = Cache::instance('file')->get('foo');
	 *
	 *     // Retrieve cache entry from file group and return 'bar' if miss
	 *     $data = Cache::instance('file')->get('foo', 'bar');
	 *
	 * @param   string   $id       id of cache to entry
	 * @param   string   $default  default value to return if cache miss
	 * @return  mixed
	 * @throws  Cache_Exception
	 */
	public function get($id, $default = NULL)
	{
		$filename = Cache_File::filename($this->_sanitize_id($id));
		$directory = $this->_resolve_directory($filename);

		// Wrap operations in try/catch to handle notices
		try
		{
			// Open file
			$file = new SplFileInfo($directory.$filename);

			// If file does not exist
			if ( ! $file->isFile())
			{
				// Return default value
				return $default;
			}
			else
			{
				// Test the expiry
				if ($this->_is_expired($file))
				{
					// Delete the file
					$this->_delete_file($file, FALSE, TRUE);
					return $default;
				}

				// open the file to read data
				$data = $file->openFile();

				// Run first fgets(). Cache data starts from the second line
				// as the first contains the lifetime timestamp
				$data->fgets();

				$cache = '';

				while ($data->eof() === FALSE)
				{
					$cache .= $data->fgets();
				}

				return unserialize($cache);
			}

		}
		catch (ErrorException $e)
		{
			// Handle ErrorException caused by failed unserialization
			if ($e->getCode() === E_NOTICE)
			{
				throw new Cache_Exception(__METHOD__.' failed to unserialize cached object with message : '.$e->getMessage());
			}

			// Otherwise throw the exception
			throw $e;
		}
	}

	/**
	 * Set a value to cache with id and lifetime
	 *
	 *     $data = 'bar';
	 *
	 *     // Set 'bar' to 'foo' in file group, using default expiry
	 *     Cache::instance('file')->set('foo', $data);
	 *
	 *     // Set 'bar' to 'foo' in file group for 30 seconds
	 *     Cache::instance('file')->set('foo', $data, 30);
	 *
	 * @param   string   $id        id of cache entry
	 * @param   string   $data      data to set to cache
	 * @param   integer  $lifetime  lifetime in seconds
	 * @return  boolean
	 */
	public function set($id, $data, $lifetime = NULL)
	{
		$filename = Cache_File::filename($this->_sanitize_id($id));
		$directory = $this->_resolve_directory($filename);

		// If lifetime is NULL
		if ($lifetime === NULL)
		{
			// Set to the default expiry
			$lifetime = Arr::get($this->_config, 'default_expire', Cache::DEFAULT_EXPIRE);
		}

		// Open directory
		$dir = new SplFileInfo($directory);

		// If the directory path is not a directory
		if ( ! $dir->isDir())
		{
			$this->_make_directory($directory, 0777, TRUE);
		}

		// Open file to inspect
		$resouce = new SplFileInfo($directory.$filename);
		$file = $resouce->openFile('w');

		try
		{
			$data = $lifetime."\n".serialize($data);
			$file->fwrite($data, strlen($data));
			return (bool) $file->fflush();
		}
		catch (ErrorException $e)
		{
			// If serialize through an error exception
			if ($e->getCode() === E_NOTICE)
			{
				// Throw a caching error
				throw new Cache_Exception(__METHOD__.' failed to serialize data for caching with message : '.$e->getMessage());
			}

			// Else rethrow the error exception
			throw $e;
		}
	}

	/**
	 * Delete a cache entry based on id
	 *
	 *     // Delete 'foo' entry from the file group
	 *     Cache::instance('file')->delete('foo');
	 *
	 * @param   string   $id  id to remove from cache
	 * @return  boolean
	 */
	public function delete($id)
	{
		$filename = Cache_File::filename($this->_sanitize_id($id));
		$directory = $this->_resolve_directory($filename);

		return $this->_delete_file(new SplFileInfo($directory.$filename), FALSE, TRUE);
	}

	/**
	 * Delete all cache entries.
	 *
	 * Beware of using this method when
	 * using shared memory cache systems, as it will wipe every
	 * entry within the system for all clients.
	 *
	 *     // Delete all cache entries in the file group
	 *     Cache::instance('file')->delete_all();
	 *
	 * @return  boolean
	 */
	public function delete_all()
	{
		return $this->_delete_file($this->_cache_dir, TRUE);
	}

	/**
	 * Garbage collection method that cleans any expired
	 * cache entries from the cache.
	 *
	 * @return  void
	 */
	public function garbage_collect()
	{
		$this->_delete_file($this->_cache_dir, TRUE, FALSE, TRUE);
		return;
	}

	/**
	 * Deletes files recursively and returns FALSE on any errors
	 *
	 *     // Delete a file or folder whilst retaining parent directory and ignore all errors
	 *     $this->_delete_file($folder, TRUE, TRUE);
	 *
	 * @param   SplFileInfo  $file                     file
	 * @param   boolean      $retain_parent_directory  retain the parent directory
	 * @param   boolean      $ignore_errors            ignore_errors to prevent all exceptions interrupting exec
	 * @param   boolean      $only_expired             only expired files
	 * @return  boolean
	 * @throws  Cache_Exception
	 */
	protected function _delete_file(SplFileInfo $file, $retain_parent_directory = FALSE, $ignore_errors = FALSE, $only_expired = FALSE)
	{
		// Allow graceful error handling
		try
		{
			// If is file
			if ($file->isFile())
			{
				try
				{
					// Handle ignore files
					if (in_array($file->getFilename(), $this->config('ignore_on_delete')))
					{
						$delete = FALSE;
					}
					// If only expired is not set
					elseif ($only_expired === FALSE)
					{
						// We want to delete the file
						$delete = TRUE;
					}
					// Otherwise...
					else
					{
						// Assess the file expiry to flag it for deletion
						$delete = $this->_is_expired($file);
					}

					// If the delete flag is set delete file
					if ($delete === TRUE)
						return unlink($file->getRealPath());
					else
						return FALSE;
				}
				catch (ErrorException $e)
				{
					// Catch any delete file warnings
					if ($e->getCode() === E_WARNING)
					{
						throw new Cache_Exception(__METHOD__.' failed to delete file : :file', array(':file' => $file->getRealPath()));
					}
				}
			}
			// Else, is directory
			elseif ($file->isDir())
			{
				// Create new DirectoryIterator
				$files = new DirectoryIterator($file->getPathname());

				// Iterate over each entry
				while ($files->valid())
				{
					// Extract the entry name
					$name = $files->getFilename();

					// If the name is not a dot
					if ($name != '.' AND $name != '..')
					{
						// Create new file resource
						$fp = new SplFileInfo($files->getRealPath());
						// Delete the file
						$this->_delete_file($fp, $retain_parent_directory, $ignore_errors, $only_expired);
					}

					// Move the file pointer on
					$files->next();
				}

				// If set to retain parent directory, return now
				if ($retain_parent_directory)
				{
					return TRUE;
				}

				try
				{
					// Remove the files iterator
					// (fixes Windows PHP which has permission issues with open iterators)
					unset($files);

					// Try to remove the parent directory
					return rmdir($file->getRealPath());
				}
				catch (ErrorException $e)
				{
					// Catch any delete directory warnings
					if ($e->getCode() === E_WARNING)
					{
						throw new Cache_Exception(__METHOD__.' failed to delete directory : :directory', array(':directory' => $file->getRealPath()));
					}
					throw $e;
				}
			}
			else
			{
				// We get here if a file has already been deleted
				return FALSE;
			}
		}
		// Catch all exceptions
		catch (Exception $e)
		{
			// If ignore_errors is on
			if ($ignore_errors === TRUE)
			{
				// Return
				return FALSE;
			}
			// Throw exception
			throw $e;
		}
	}

	/**
	 * Resolves the cache directory real path from the filename
	 *
	 *      // Get the realpath of the cache folder
	 *      $realpath = $this->_resolve_directory($filename);
	 *
	 * @param   string  $filename  filename to resolve
	 * @return  string
	 */
	protected function _resolve_directory($filename)
	{
		return $this->_cache_dir->getRealPath().DIRECTORY_SEPARATOR.$filename[0].$filename[1].DIRECTORY_SEPARATOR;
	}

	/**
	 * Makes the cache directory if it doesn't exist. Simply a wrapper for
	 * `mkdir` to ensure DRY principles
	 *
	 * @link    http://php.net/manual/en/function.mkdir.php
	 * @param   string    $directory    directory path
	 * @param   integer   $mode         chmod mode
	 * @param   boolean   $recursive    allows nested directories creation
	 * @param   resource  $context      a stream context
	 * @return  SplFileInfo
	 * @throws  Cache_Exception
	 */
	protected function _make_directory($directory, $mode = 0777, $recursive = FALSE, $context = NULL)
	{
		// call mkdir according to the availability of a passed $context param
		$mkdir_result = $context ?
			mkdir($directory, $mode, $recursive, $context) :
			mkdir($directory, $mode, $recursive);

		// throw an exception if unsuccessful
		if ( ! $mkdir_result)
		{
			throw new Cache_Exception('Failed to create the defined cache directory : :directory', array(':directory' => $directory));
		}

		// chmod to solve potential umask issues
		chmod($directory, $mode);

		return new SplFileInfo($directory);
	}

	/**
	 * Test if cache file is expired
	 *
	 * @param SplFileInfo $file the cache file
	 * @return boolean TRUE if expired false otherwise
	 */
	protected function _is_expired(SplFileInfo $file)
	{
		// Open the file and parse data
		$created = $file->getMTime();
		$data = $file->openFile("r");
		$lifetime = (int) $data->fgets();

		// If we're at the EOF at this point, corrupted!
		if ($data->eof())
		{
			throw new Cache_Exception(__METHOD__ . ' corrupted cache file!');
		}

		//close file
		$data = null;

		// test for expiry and return
		return (($lifetime !== 0) AND ( ($created + $lifetime) < time()));
	}
}

　　

4、使用

$key = 'AjSR/piQT24JaYEgh6V9tA==';
$data = array('id'=>1, 'name'=>'liuchao');
Cache::instance("file")->set($key, $data, 60);