/**
 * jCache - A client cache plugin for jQuery
 * Should come in handy when data needs to be cached in client to improve performance.
 * Author:  Phan Van An 
 *      phoenixheart@gmail.com
 *      http://www.skidvn.com
 * License : Read jQuery's license

Usage:
    1.  Include this plugin into your web document after jQuery:
      <script type="text/javascript" src="js/jquery.jcache.js"></script>
    2.  [OPTIONAL] Set the max cached item number, for example 20
      $.jCache.maxSize = 20; 
    3.  Start playing around with it:
      - Put an item into cache: $.jCache.setItem(theKey, the Value);
      - Retrieve an item from cache: var theValue = $.jCache.getItem(theKey);
      - ...
 */
(function (jQuery){
  this.version = '(beta)(0.0.1)';
  
  /**
   * The maximum items this cache should hold. 
   * If the cache is going to be overload, oldest item will be deleted (FIFO).
   * Since the cached object is retained inside browser's state, 
   * a too big value on a too big web apps may affect system memory.
   * Default is 10.
   */
  this.maxSize = 10;
  
    /**
     * An array to keep track of the cache keys
     */
  this.keys = new Array();
  
  /**
   * Number of currently cached items
   */
  this.cache_length = 0;
  
  /**
   * An associated array to contain the cached items
   */
  this.items = new Array();
  
  /*
   * @desc  Puts an item into the cache
   *
   * @param string Key of the item
   * @param   string Value of the item
   * @return  string Value of the item
   */
  this.setItem = function(pKey, pValue)
  {
    if (typeof(pValue) != 'undefined') 
    {
      if (typeof(this.items[pKey]) == 'undefined') 
      {
        this.cache_length++;
      }

      this.keys.push(pKey);
      this.items[pKey] = pValue;
      
      if (this.cache_length > this.maxSize)
      {
        this.removeOldestItem();
      }
    }
     
    return pValue;
  }
  
  /*
   * @desc  Removes an item from the cache using its key
   * @param   string Key of the item
   */
  this.removeItem = function(pKey)
  {
    var tmp;
    if (typeof(this.items[pKey]) != 'undefined') 
    {
      this.cache_length--;
      var tmp = this.items[pKey];
      delete this.items[pKey];
    }
     
    return tmp;
  }

  /*
   * @desc  Retrieves an item from the cache by its key
   *
   * @param   string Key of the item
   * @return  string Value of the item
   */
  this.getItem = function(pKey) 
  {
    return this.items[pKey];
  }

  /*
   * @desc  Indicates if the cache has an item specified by its key
   * @param   string Key of the item
   * @return  boolean TRUE or FALSE
   */
  this.hasItem = function(pKey)
  {
    return typeof(this.items[pKey]) != 'undefined';
  }
  
  /**
   * @desc  Removes the oldest cached item from the cache
   */
  this.removeOldestItem = function()
  {
    this.removeItem(this.keys.shift());
  }
  
  /**
   * @desc  Clears the cache
   * @return  Number of items cleared
   */
  this.clear = function()
  {
    var tmp = this.cache_length;
    this.keys = new Array();
    this.cache_length = 0;
    this.items = new Array();
    return tmp;
  }
  
  jQuery.jCache = this;
  return jQuery;
})(jQuery);