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// created on 29/11/2007
// Npgsql.NpgsqlConnectionStringBuilder.cs
//
// Author:
// Glen Parker (glenebob@nwlink.com)
// Ben Sagal (bensagal@gmail.com)
// Tao Wang (dancefire@gmail.com)
//
// Copyright (C) 2007 The Npgsql Development Team
// npgsql-general@gborg.postgresql.org
// http://gborg.postgresql.org/project/npgsql/projdisplay.php
//
// Permission to use, copy, modify, and distribute this software and its
// documentation for any purpose, without fee, and without a written
// agreement is hereby granted, provided that the above copyright notice
// and this paragraph and the following two paragraphs appear in all copies.
//
// IN NO EVENT SHALL THE NPGSQL DEVELOPMENT TEAM BE LIABLE TO ANY PARTY
// FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
// INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
// DOCUMENTATION, EVEN IF THE NPGSQL DEVELOPMENT TEAM HAS BEEN ADVISED OF
// THE POSSIBILITY OF SUCH DAMAGE.
//
// THE NPGSQL DEVELOPMENT TEAM SPECIFICALLY DISCLAIMS ANY WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
// ON AN "AS IS" BASIS, AND THE NPGSQL DEVELOPMENT TEAM HAS NO OBLIGATIONS
// TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
using System;
using System.Collections.Generic;
//using System.Text;
namespace Npgsql
{
internal class Cache<TEntity> : LinkedList<KeyValuePair<string, TEntity>>
where TEntity : class
{
private int _cache_size = 20;
private object locker = new object();
/// <summary>
/// Set Cache Size. The default value is 20.
/// </summary>
public int CacheSize
{
get { return _cache_size; }
set
{
if (value < 0) { throw new ArgumentOutOfRangeException("CacheSize"); }
_cache_size = value;
if (this.Count > _cache_size)
{
lock (locker)
{
while (_cache_size < this.Count)
{
RemoveLast();
}
}
}
}
}
/// <summary>
/// Lookup cached entity. null will returned if not match.
/// For both get{} and set{} apply LRU rule.
/// </summary>
/// <param name="key">key</param>
/// <returns></returns>
public TEntity this[string key]
{
get
{
lock (locker)
{
for (LinkedListNode<KeyValuePair<string, TEntity>> node = this.First; node != null; node = node.Next)
{
if (node.Value.Key == key)
{
this.Remove(node);
this.AddFirst(node);
return node.Value.Value;
}
}
}
return null;
}
set
{
lock (locker)
{
for (LinkedListNode<KeyValuePair<string, TEntity>> node = this.First; node != null; node = node.Next)
{
if (node.Value.Key == key)
{
this.Remove(node);
this.AddFirst(node);
return;
}
}
if (this.CacheSize > 0)
{
this.AddFirst(new KeyValuePair<string, TEntity>(key, value));
if (this.Count > this.CacheSize)
{
this.RemoveLast();
}
}
}
}
}
public Cache() : base() { }
public Cache(int cacheSize) : base()
{
this._cache_size = cacheSize;
}
}
}