Ramakrishna's Code Project Screen Saver

using System;
using CP.Apps.ScreenSaver.com.codeproject.www;

namespace CP.Apps.ScreenSaver.Data
{
	/// <summary>
	/// A class for updating messages
	/// </summary>
	public abstract class MessageUpdate : IPresentationDataUpdater
	{
		protected LatestBrief webService;
		
		protected abstract MessageBrief[] Messages
		{
			get;
		}

		protected abstract int UpdatePeriod
		{
			get;
		}
		
		#region Implementation of IPresentationDataUpdater
		public bool UpdatePresentationData(CP.Apps.ScreenSaver.Data.PresentationData data)
		{
			try
			{
				webService = new LatestBrief();

				MessageBrief[] messages = this.Messages;
				
				PresentationItem[] items = new PresentationItem[messages.Length];
				data.UpdateType = this.GetType().FullName;
					
				for(int i = 0; i < messages.Length; i++)
				{
					PresentationItem item = new PresentationItem();
					item.Author = Util.StripHtml(messages[i].Author);
					item.Text = String.Format("{0} ({1})", Util.StripHtml(messages[i].Subject), messages[i].MsgsInThread);

					items[i] = item;
				}
				
				data.Items = items;

				//Update the update interval
				data.UpdateInterval = this.UpdatePeriod;	
			}
			finally
			{
				if (webService != null)
				{
					webService.Dispose();
					webService = null;
				}
			}

			return true;
		}
	
		#endregion
	}
	
	public class LoungeUpdate : MessageUpdate
	{
		protected override CP.Apps.ScreenSaver.com.codeproject.www.MessageBrief[] Messages
		{
			get
			{
				return webService.GetLatestLoungeBrief(webService.GetMaxLoungeListLength());
			}
		}

		protected override int UpdatePeriod
		{
			get
			{
				return webService.GetLoungeLatestUpdatePeriod();
			}
		}
	}

	public class CommentsUpdate : MessageUpdate
	{
		protected override CP.Apps.ScreenSaver.com.codeproject.www.MessageBrief[] Messages
		{
			get
			{
				return webService.GetLatestCommentsBrief(webService.GetMaxCommentListLength());
			}
		}

		protected override int UpdatePeriod
		{
			get
			{
				return webService.GetCommentLatestUpdatePeriod();
			}
		}
	}
}