using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Mesnac.Basic
{
    /// <summary>
    /// 全局缓存工厂类
    /// </summary>
    public class CacheFactory
    {
        #region 单例实现

        private static CacheFactory _instance = null;           //静态成员

        /// <summary>
        /// 私有构造方法
        /// </summary>
        private CacheFactory()
        {

        }

        /// <summary>
        /// 缓存工厂静态实例
        /// </summary>
        public static CacheFactory Instance
        {
            get
            {
                lock(String.Empty)
                {
                    if (_instance == null)
                    {
                        _instance = new CacheFactory();
                    }
                    return _instance;
                }
            }
        }

        #endregion

        #region 字段定义

        private Dictionary<string, object> dic = new Dictionary<string, object>();

        #endregion

        #region 方法定义

        /// <summary>
        /// 判断缓存工厂中是否存在指定的缓存项
        /// </summary>
        /// <param name="key">缓存的key值</param>
        /// <returns>存在返回true，不存在返回false</returns>
        public bool ContainsKey(string key)
        {
            return this.dic.ContainsKey(key);
        }

        /// <summary>
        /// 缓存方法
        /// </summary>
        /// <typeparam name="T">缓存对象的类型</typeparam>
        /// <param name="key">缓存的key值</param>
        /// <param name="value">缓存的对象值</param>
        public void Cache<T>(string key, T value)
        {
            this.dic[key] = value;
        }

        /// <summary>
        /// 从缓存中获取对象
        /// </summary>
        /// <typeparam name="T">缓存对象的类型</typeparam>
        /// <param name="key">缓存的key值</param>
        /// <returns>返回缓存对象值</returns>
        public T Get<T>(string key)
        {
            if (this.dic.ContainsKey(key))
            {
                object value = this.dic[key];
                return (T)value;
            }
            return default(T);
        }

        /// <summary>
        /// 清空指定的缓存对象
        /// </summary>
        /// <param name="key">缓存的key值</param>
        public void ClearByKey(string key)
        {
            if (this.dic.ContainsKey(key))
            {
                this.dic.Remove(key);
            }
        }

        /// <summary>
        /// 清空所有缓存对象
        /// </summary>
        public void ClearAll()
        {
            this.dic.Clear();
        }

        #endregion
    }
}