标签：efault retrieve 代码 lis 编写 storage ica 库项目 text
适配器模式绝对是软件开发当中最受关注的设计模式之一。
正如标题所说，我会直截了当的告诉你什么是适配器模式，不说太多的废话，因为设计模式这种东西需要慢慢的去体会。只有多思多闻，才能领会这些模式真的是设计的很巧妙。
public class Customer
{
}
public interface ICustomerRepository
{
IList<Customer> GetCustomers();
}
public class CustomerService
{
private readonly ICustomerRepository _customerRepository;
public CustomerService(ICustomerRepository customerRepository)
{
_customerRepository = customerRepository;
}
public IList<Customer> GetAllCustomers()
{
IList<Customer> customers;
string storageKey = "GetAllCustomers";
customers = (List<Customer>)HttpContext.Current.Cache.Get(storageKey);
if (customers == null)
{
customers = _customerRepository.GetCustomers();
HttpContext.Current.Cache.Insert(storageKey, customers);
}
return customers;
}
}
上面的代码有什么问题？
解决办法：
public interface ICacheStorage
{
void Remove(string key);
void Store(string key, object data);
T Retrieve<T>(string key);
}
public class CustomerService
{
private readonly ICustomerRepository _customerRepository;
private readonly ICacheStorage _cacheStorage;
public CustomerService(ICustomerRepository customerRepository, ICacheStorage cacheStorage)
{
_customerRepository = customerRepository;
_cacheStorage = cacheStorage;
}
public IList<Customer> GetAllCustomers()
{
IList<Customer> customers;
string storageKey = "GetAllCustomers";
customers = _cacheStorage.Retrieve<List<Customer>>(storageKey);
if (customers == null)
{
customers = _customerRepository.GetCustomers();
_cacheStorage.Store(storageKey, customers);
}
return customers;
}
}
public class HttpContextCacheStorage : ICacheStorage
{
public void Remove(string key)
{
HttpContext.Current.Cache.Remove(key);
}
public void Store(string key, object data)
{
HttpContext.Current.Cache.Insert(key, data);
}
public T Retrieve<T>(string key)
{
T itemsStored = (T)HttpContext.Current.Cache.Get(key);
if (itemsStored == null)
{
itemsStored = default(T);
}
return itemsStored;
}
}
我们已经封装了一个HttpContext缓存对象的适配器类，下一步是使用ICacheStorage接口注入它，不在本文讨论范围之内。将来如果使用不同的缓存方案，那么需要做的就是编写其他的适配器 如 Memcache,Redis。好了，就是这么直截了当。
标签：efault retrieve 代码 lis 编写 storage ica 库项目 text
原文地址：http://www.cnblogs.com/bidianqing/p/7188326.html
