enterprisecountercollection.cs

用于c#.net数据库操作的类库。能把结婚集以数组的形成操作。

using System;
using System.Reflection;
using System.Threading;
using System.Collections;
using System.Diagnostics;

namespace EnterpriseObjects
{
	/// <summary>
	/// Summary description for CounterCollection.
	/// </summary>
	public class EnterpriseCounterCollection : CollectionBase
	{
		// members...
		private ReaderWriterLock _lock = new ReaderWriterLock();
		private Hashtable _cache;

		public EnterpriseCounterCollection()
		{
		}

		public void Add(EnterpriseCounter counter)
		{
			// have we already added it?
			EnterpriseCounter existing = Find(counter.Name);
			if(existing != null)
				return;

			// add it...
			_lock.AcquireWriterLock(-1);
			List.Add(counter);
			ClearCache();
			_lock.ReleaseWriterLock();
		}

		public void Remove(EnterpriseCounter counter)
		{
			_lock.AcquireWriterLock(-1);
			List.Remove(counter);
			ClearCache();
			_lock.ReleaseWriterLock();
		}

		public new void Clear()
		{
			_lock.AcquireWriterLock(-1);
			base.Clear();
			ClearCache();
			_lock.ReleaseWriterLock();
		}

		public new void RemoveAt(int index)
		{
			_lock.AcquireWriterLock(-1);
			base.RemoveAt(index);
			ClearCache();
			_lock.ReleaseWriterLock();
		}
		
		public new int Count
		{
			get
			{
				_lock.AcquireReaderLock(-1);
				int theCount = base.Count;
				_lock.ReleaseWriterLock();
				return theCount;
			}
		}

		public EnterpriseCounter this[int index]
		{
			get
			{
				_lock.AcquireReaderLock(-1);
				EnterpriseCounter theItem = (EnterpriseCounter)List[index];
				_lock.ReleaseReaderLock();
				return theItem;
			}
			set
			{
				_lock.AcquireWriterLock(-1);
				List[index] = value;
				ClearCache();
				_lock.ReleaseWriterLock();
			}
		}

		protected void ClearCache()
		{
			_lock.AcquireWriterLock(-1);
			_cache = null;
			_lock.ReleaseWriterLock();
		}

		protected void CheckCacheExists()
		{
			// lock...
			_lock.AcquireReaderLock(-1);

			// do we have it?
			if(_cache == null)
			{
				// upgrade...
				_lock.UpgradeToWriterLock(-1);

				// create it...
				_cache = new Hashtable();
				foreach(EnterpriseCounter counter in InnerList)
					_cache.Add(counter.Name.ToLower(), counter);
			}

			// unlock...
			_lock.ReleaseLock();
		}

		public EnterpriseCounter Find(string name)
		{
			// do we have a cache?
			CheckCacheExists();

			// loop...
			_lock.AcquireReaderLock(-1);
			EnterpriseCounter found = (EnterpriseCounter)_cache[name.ToLower()];
			_lock.ReleaseReaderLock();

			// return...
			return found;
		}

		public bool Exists(string name) 
		{
			// do we have a cache?
			CheckCacheExists();

			// exists?
			_lock.AcquireReaderLock(-1);
			bool counterExists = _cache.Contains(name.ToLower());
			_lock.ReleaseReaderLock();

			// return...
			return counterExists;
		}
	}
}