一个强大的PHP缓存类(2)

        if ($value!=''){//wants to write
            if ($ttl=='') $ttl=$this->cache_expire;
            $this->put($key, $value,$ttl);
        }
        else return $this->get($key);//reading value
    }
    
    //creates new cache files with the given data, $key== name of the cache, data the info/values to store
    private function put($key,$data,$ttl='' ){
        if ($ttl=='') $ttl=$this->cache_expire;
        
        switch($this->cache_type){
            case 'eaccelerator':
                eaccelerator_put($key, serialize($data), $ttl);
            break;
 
            case 'apc':
                apc_store($key, $data, $ttl);
            break;
 
            case 'xcache':
                xcache_set($key, serialize($data), $ttl);
            break;
 
            case 'memcache':
                $data=serialize($data);
                if (!$this->cache_external->replace($key, $data, false, $ttl))
                $this->cache_external->set($key, $data, false, $ttl);
            break;
            
            case 'filecache':
                $this->cache_external->cache($key,$data);
            break;
        }  
    }
    
    //returns cache for the given key
    private function get($key){
        switch($this->cache_type){
            case 'eaccelerator':
                $data =  @unserialize(eaccelerator_get($key));
            break;
 
            case 'apc':
                $data =  apc_fetch($key);
            break;
 
            case 'xcache':
                $data =  @unserialize(xcache_get($key));
            break;
 
            case 'memcache':
                $data = @unserialize($this->cache_external->get($key));
            break;
            
            case 'filecache':
                $data = $this->cache_external->cache($key);
            break;