Subversion-Projekte lars-tiefland.prado

<?php
/**
 * TSqlMapCacheModel, TSqlMapCacheTypes and TSqlMapCacheKey classes file.
 *
 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2008 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @version $Id: TSqlMapCacheModel.php 2541 2008-10-21 15:05:13Z qiang.xue $
 * @package System.Data.SqlMap.Configuration
 */

/**
 * TSqlMapCacheModel corresponds to the <cacheModel> sql mapping configuration tag.
 *
 * The results from a query Mapped Statement can be cached simply by specifying
 * the {@link CacheModel TSqlMapStatement::setCacheModel()} property in <statement> tag.
 * A cache model is a configured cache that is defined within the sql map
 * configuration file. Cache models are configured using the <cacheModel> element.
 *
 * The cache model uses a pluggable framework for supporting different types of
 * caches. The choice of cache is specified by the {@link Implementation setImplementation()}
 * property. The class name specified must be one of {@link TSqlMapCacheTypes}.
 *
 * The cache implementations, LRU and FIFO cache below do not persist across
 * requests. That is, once the request is complete, all cache data is lost.
 * These caches are useful queries that results in the same repeated data during
 * the current request.
 *
 * @author Wei Zhuo <weizho[at]gmail[dot]com>
 * @version $Id: TSqlMapCacheModel.php 2541 2008-10-21 15:05:13Z qiang.xue $
 * @package System.Data.SqlMap.Configuration
 * @since 3.1
 */
class TSqlMapCacheModel extends TComponent
{
        private $_cache;
        private $_hits = 0;
        private $_requests = 0;
        private $_id;
        private $_implementation='basic';
        private $_properties = array();

        /**
         * @return string unique cache model identifier.
         */
        public function getID()
        {
                return $this->_id;
        }

        /**
         * @param string unique cache model identifier.
         */
        public function setID($value)
        {
                $this->_id = $value;
        }

        /**
         * @return string cache implements of TSqlMapCacheTypes, either 'Basic', 'LRU' or 'FIFO'.
         */
        public function getImplementation()
        {
                return $this->_implementation;
        }

        /**
         * @param string cache implements of TSqlMapCacheTypes, either 'Basic', 'LRU' or 'FIFO'.
         */
        public function setImplementation($value)
        {
                $this->_implementation = TPropertyValue::ensureEnum($value,'TSqlMapCacheTypes');
        }

        /**
         * Initialize the cache implementation, sets the actual cache contain if supplied.
         * @param ISqLMapCache cache implementation instance.
         */
        public function initialize($cache=null)
        {
                if(is_null($cache))
                        $this->_cache= Prado::createComponent($this->getImplementationClass());
                else
                        $this->_cache=$cache;
        }

        /**
         * @return string cache implementation class name.
         */
        public function getImplementationClass()
        {
                switch(TPropertyValue::ensureEnum($this->_implementation,'TSqlMapCacheTypes'))
                {
                        case TSqlMapCacheTypes::FIFO: return 'TSqlMapFifoCache';
                        case TSqlMapCacheTypes::LRU : return 'TSqlMapLruCache';
                        case TSqlMapCacheTypes::Basic : return 'TSqlMapApplicationCache';
                }
        }

        /**
         * Register a mapped statement that will trigger a cache flush.
         * @param TMappedStatement mapped statement that may flush the cache.
         */
        public function registerTriggerStatement($mappedStatement)
        {
                $mappedStatement->attachEventHandler('OnExecuteQuery',array($this, 'flush'));
        }

        /**
         * Clears the cache.
         */
        public function flush()
        {
                $this->_cache->flush();
        }

        /**
         * @param TSqlMapCacheKey|string cache key
         * @return mixed cached value.
         */
        public function get($key)
        {
                if($key instanceof TSqlMapCacheKey)
                        $key = $key->getHash();

                //if flush ?
                $value = $this->_cache->get($key);
                $this->_requests++;
                if(!is_null($value))
                        $this->_hits++;
                return $value;
        }

        /**
         * @param TSqlMapCacheKey|string cache key
         * @param mixed value to be cached.
         */
        public function set($key, $value)
        {
                if($key instanceof TSqlMapCacheKey)
                        $key = $key->getHash();

                if(!is_null($value))
                        $this->_cache->set($key, $value);
        }

        /**
         * @return float cache hit ratio.
         */
        public function getHitRatio()
        {
                if($this->_requests != 0)
                        return $this->_hits / $this->_requests;
                else
                        return 0;
        }
}

/**
 * TSqlMapCacheTypes enumerable class.
 *
 * Implemented cache are 'Basic', 'FIFO' and 'LRU'.
 *
 * @author Wei Zhuo <weizho[at]gmail[dot]com>
 * @version $Id: TSqlMapCacheModel.php 2541 2008-10-21 15:05:13Z qiang.xue $
 * @package System.Data.SqlMap.Configuration
 * @since 3.1
 */
class TSqlMapCacheTypes extends TEnumerable
{
        const Basic='Basic';
        const FIFO='FIFO';
        const LRU='LRU';
}

/**
 * TSqlMapCacheKey class.
 *
 * Provides a hash of the object to be cached.
 *
 * @author Wei Zhuo <weizho[at]gmail[dot]com>
 * @version $Id: TSqlMapCacheModel.php 2541 2008-10-21 15:05:13Z qiang.xue $
 * @package System.Data.SqlMap.Configuration
 * @since 3.1
 */
class TSqlMapCacheKey
{
        private $_key;

        /**
         * @param mixed object to be cached.
         */
        public function __construct($object)
        {
                $this->_key = $this->generateKey(serialize($object));
        }

        /**
         * @param string serialized object
         * @return string crc32 hash of the serialized object.
         */
        protected function generateKey($string)
        {
                return sprintf('%x',crc32($string));
        }

        /**
         * @return string object hash.
         */
        public function getHash()
        {
                return $this->_key;
        }
}