function Cache(maxlen)
{
    var _cache = {};
    var _length = 0;
    var _maxLength = maxlen || 40;
    this.addItem = function (key, item) {
        if (_length == _maxLength) {
            _cache[0] = null;
            --_length;
        }

        _cache[key] = item;
        ++_length;
    }
    this.getItem = function (key) { return _cache[key]; }
    this.removeItem = function (key) { _cache[key] = null; }
    this.getLength = function () { return parseInt(length); }
}