<?php
  /**
   * Copyright (c) 2013 Robin Appelman <icewind@owncloud.com>
   * This file is licensed under the Affero General Public License version 3 or
   * later.
   * See the COPYING-README file.
   */
  
  namespace OC\Memcache;
  
  abstract class Cache implements \ArrayAccess {
  	/**
  	 * @var string $prefix
  	 */
  	protected $prefix;
  
  	/**
  	 * @param string $prefix
  	 */
  	public function __construct($prefix = '') {
  		$this->prefix = \OC_Util::getInstanceId() . '/' . $prefix;
  	}
  
  	public function getPrefix() {
  		return $this->prefix;
  	}
  
  	/**
  	 * @param string $key
  	 * @return mixed
  	 */
  	abstract public function get($key);
  
  	/**
  	 * @param string $key
  	 * @param mixed $value
  	 * @param int $ttl
  	 * @return mixed
  	 */
  	abstract public function set($key, $value, $ttl = 0);
  
  	/**
  	 * @param string $key
  	 * @return mixed
  	 */
  	abstract public function hasKey($key);
  
  	/**
  	 * @param string $key
  	 * @return mixed
  	 */
  	abstract public function remove($key);
  
  	/**
  	 * @param string $prefix
  	 * @return mixed
  	 */
  	abstract public function clear($prefix = '');
  
  	//implement the ArrayAccess interface
  
  	public function offsetExists($offset) {
  		return $this->hasKey($offset);
  	}
  
  	public function offsetSet($offset, $value) {
  		$this->set($offset, $value);
  	}
  
  	public function offsetGet($offset) {
  		return $this->get($offset);
  	}
  
  	public function offsetUnset($offset) {
  		$this->remove($offset);
  	}
  }