function FQKTask(params) { this.params = params; }
FQKTask.prototype = {func: undefined};

function FQKTaskQueue() {
    this._pendingTasks = [];
    this._runningTasks = [];
}
FQKTaskQueue.prototype = {
    _maxOperationCount: 1,
    _pendingTasks: undefined,
    _runningTasks: undefined,
    isFunction: function (functionToCheck) {
        var getType = {};
        return functionToCheck && getType.toString.call(functionToCheck) === '[object Function]';
    },
    setMaxOperationCount: function (count) {
        if(count > 0)
        {
            this._maxOperationCount = Number(count);
        }
    },
    addTask: function (task) {
        if(!(task instanceof FQKTask))
        {
            return ;
        }

        if(!this.isFunction(task.func))
        {
            throw new Error('You must define task\'s func');
        }

        if(this._runningTasks.length < this._maxOperationCount)
        {
            this._runningTasks.push(task);
            task.func(task);
        }
        else
        {
            this._pendingTasks.push(task);
        }
    },
    removeTask: function (task) {
        if(!(task instanceof FQKTask))
        {
            return ;
        }

        var index = this._runningTasks.indexOf(task);
        if (index >= 0) {
            this._runningTasks.splice(index, 1);
        }

        if(this._pendingTasks.length > 0)
        {
            var pendingTask = this._pendingTasks[0];
            this._pendingTasks.splice(0, 1);
            this.addTask(pendingTask);
        }
    }
};