在C#中用匿名函数来更方便的使用缓存
一个数据缓存，一般由数据来源，缓存方案，缓存读取来完成，现在有了匿名函数，可以把获取数据来源变为匿名函数。这样就可以直接声明一个缓存： protected static CacheManager Company
一个数据缓存，一般由数据来源，缓存方案，缓存读取来完成，现在有了匿名函数，可以把获取数据来源变为匿名函数。这样就可以直接声明一个缓存：
protected static CacheManager<Company> companyCache = new CacheManager<Company>(new SmsDatabaseCache<Company>(), (key) =>
{
return SmsDatabase.Instance.Context.Company.Where(c => c.ShortNumber == (string)key).SingleOrDefault();
});
SmsDatabaseCache
public class SmsDatabaseCache<TData> : ICache<TData>
{
private Dictionary<object, TData> cache = new Dictionary<object, TData>();
public SmsDatabaseCache()
{
SmsDatabase.Instance.PreDisposing += (s, e) =>
{
cache.Clear();
};
}
public TData Get(object key)
{
return cache[key];
}
public void Set(object key, TData data)
{
cache[key] = data;
}
}
实现代码如下：缓存代码
using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
namespace Evlon.Utils
{
public interface ICache<TData>
{
TData Get(object key);
void Set(object key, TData data);
}
public interface ICacheManager<TData> : ICache<TData>
{
Func<object, TData> SourceGetter { get; }
}
public class SimpleCache<TData> : ICache<TData>
{
private Dictionary<object, TData> cache = new Dictionary<object, TData>();
#region ICacheManager<TData> 成员
public TData Get(object key)
{
return cache[key];
}
public void Set(object key, TData data)
{
cache[key] = data;
}
#endregion
}
public class TimeoutCache<TData> : ICache<TData>
{
public TimeSpan Expire {get;set;}
private DateTime timeLastScan = DateTime.Now;
private Dictionary<object, KeyValuePair<TData, DateTime>> cache = new Dictionary<object, KeyValuePair<TData, DateTime>>();
public TimeoutCache()
{
Expire = TimeSpan.FromMinutes(5);
}
private void TryClearExpireObject()
{
TimeSpan ts = DateTime.Now - timeLastScan;
if (ts.TotalSeconds > Expire.TotalSeconds / 2)
{
timeLastScan = DateTime.Now;
cache.Where(kv => kv.Value.Value > DateTime.Now.Subtract(Expire)).ToList().ForEach(kv =>
{
cache.Remove(kv.Key);
});
}
}
#region ICacheManager<TData> 成员
public TData Get(object key)
{
TryClearExpireObject();
if(!cache.ContainsKey(key))
return default(TData);
KeyValuePair<TData, DateTime> kv = cache[key];
if (kv.Value.Add(Expire) < DateTime.Now)
{
cache.Remove(key);
return default(TData);
}
return kv.Key;
}
public void Set(object key, TData data)
{
cache[key] = new KeyValuePair<TData, DateTime>(data, DateTime.Now);
}
#endregion
}
public class CacheManager<TData> : ICacheManager<TData>
{
private ICache<TData> cache = null;
public Func<object, TData> SourceGetter { get; private set; }
public CacheManager(ICache<TData> cache, Func<object, TData> sourceGetter)
{
this.cache = cache;
this.SourceGetter = sourceGetter;
}
#region ICacheGetter<TData> 成员
public TData Get(object key)
{
TData data = cache.Get(key);
if (data != null)
return data;
data = this.SourceGetter(key);
cache.Set(key, data);
return data;
}
public void Set(object key, TData data)
{
cache.Set(key, data);
}
#endregion
}
}
{
return SmsDatabase.Instance.Context.Company.Where(c => c.ShortNumber == (string)key).SingleOrDefault();
});
SmsDatabaseCache是一个缓存方案，还可以使用SimpleCache，TimeoutCache等实现了ICache接口的类，因为我的ICacheManager从ICache继承，所以还可以实现级连缓存哟，例如：
SmsDatebaseCache是一个依SmsDatabase.Instance.Context的缓存方案，在LinqContextDispose时，会进行清空数据操作。SmsDatabaseCache public class SmsDatabaseCache<TData> : ICache<TData>
{
private Dictionary<object, TData> cache = new Dictionary<object, TData>();
public SmsDatabaseCache()
{
SmsDatabase.Instance.PreDisposing += (s, e) =>
{
cache.Clear();
};
}
public TData Get(object key)
{
return cache[key];
}
public void Set(object key, TData data)
{
cache[key] = data;
}
}
实现代码如下：
缓存代码using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
namespace Evlon.Utils
{
public interface ICache<TData>
{
TData Get(object key);
void Set(object key, TData data);
}
public interface ICacheManager<TData> : ICache<TData>
{
Func<object, TData> SourceGetter { get; }
}
public class SimpleCache<TData> : ICache<TData>
{
private Dictionary<object, TData> cache = new Dictionary<object, TData>();
#region ICacheManager<TData> 成员
public TData Get(object key)
{
return cache[key];
}
public void Set(object key, TData data)
{
cache[key] = data;
}
#endregion
}
public class TimeoutCache<TData> : ICache<TData>
{
public TimeSpan Expire {get;set;}
private DateTime timeLastScan = DateTime.Now;
private Dictionary<object, KeyValuePair<TData, DateTime>> cache = new Dictionary<object, KeyValuePair<TData, DateTime>>();
public TimeoutCache()
{
Expire = TimeSpan.FromMinutes(5);
}
private void TryClearExpireObject()
{
TimeSpan ts = DateTime.Now - timeLastScan;
if (ts.TotalSeconds > Expire.TotalSeconds / 2)
{
timeLastScan = DateTime.Now;
cache.Where(kv => kv.Value.Value > DateTime.Now.Subtract(Expire)).ToList().ForEach(kv =>
{
cache.Remove(kv.Key);
});
}
}
#region ICacheManager<TData> 成员
public TData Get(object key)
{
TryClearExpireObject();
if(!cache.ContainsKey(key))
return default(TData);
KeyValuePair<TData, DateTime> kv = cache[key];
if (kv.Value.Add(Expire) < DateTime.Now)
{
cache.Remove(key);
return default(TData);
}
return kv.Key;
}
public void Set(object key, TData data)
{
cache[key] = new KeyValuePair<TData, DateTime>(data, DateTime.Now);
}
#endregion
}
public class CacheManager<TData> : ICacheManager<TData>
{
private ICache<TData> cache = null;
public Func<object, TData> SourceGetter { get; private set; }
public CacheManager(ICache<TData> cache, Func<object, TData> sourceGetter)
{
this.cache = cache;
this.SourceGetter = sourceGetter;
}
#region ICacheGetter<TData> 成员
public TData Get(object key)
{
TData data = cache.Get(key);
if (data != null)
return data;
data = this.SourceGetter(key);
cache.Set(key, data);
return data;
}
public void Set(object key, TData data)
{
cache.Set(key, data);
}
#endregion
}
}
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