浅谈Pool对象

Pool对象的技术指标:

避免频繁创建经常使用的稀有资源,提高工作效率.

控制阀值,很多情况下一些关键资源都有一个最佳并发数,超过这个拐点性能有可能急剧下降,也有可能继续增大并发数性能不能提升.

安全的获取对象和释放对象(使用之后放回连接池)

public sealed class Pool<T> : IDisposable where T : IDisposable
{
private bool disposed = false;
private Semaphore gate;
private Stack<T> pool;
public event Predicate<T> Predicate;
public Pool(int concrrent,Func<Pool<T>,T> activator)
{
if (concrrent <= 0)
{
throw new ArgumentException("concrrent");
}
if (activator==null)
{
throw new ArgumentNullException("activator");
}
gate = new Semaphore(concrrent, concrrent);
pool = new Stack<T>();
for (int i=0;i< concrrent; i++)
{
pool.Push(activator(this));
}

}

public T Acquire()
{
if (!gate.WaitOne())
throw new InvalidOperationException();
lock (pool)
{
return pool.Pop();
}
}

public void Release(T target)
{
lock (pool)
{
if (Predicate!=null)
{
if (Predicate(target))
{
pool.Push(target);
gate.Release();
}
}
else
{
if (target != null)
{
pool.Push(target);
gate.Release();
}
}
}
}

private void Dispose(bool disposing)
{
if (disposed)
return;
if (disposing)
{
gate.Dispose();
}
for (int i = 0; i < pool.Count; i++)
{
var t = pool.Pop();
t.Dispose();
}
disposed = true;
}

public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}

~Pool()
{
Dispose(false);
}
}

T对象实现时最好与Pool对象建立某种关联,调用T对象实例的某个方法时可以将对象送回Pool,而不是销毁它.同时Pool对象Release对象时,最好通过事件(关联关系)判断是否是从Pool对象获取的,然后放回Pool.