/V4/StockTrader RI/Desktop/StockTraderRI.Modules.News/Services/NewsFeedService.cs

//===================================================================================

// Microsoft patterns & practices

// Composite Application Guidance for Windows Presentation Foundation and Silverlight

//===================================================================================

// Copyright (c) Microsoft Corporation.  All rights reserved.

// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY

// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT

// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

// FITNESS FOR A PARTICULAR PURPOSE.

//===================================================================================

// The example companies, organizations, products, domain names,

// e-mail addresses, logos, people, places, and events depicted

// herein are fictitious.  No association with any real company,

// organization, product, domain name, email address, logo, person,

// places, or events is intended or should be inferred.

//===================================================================================

using System;

using System.Collections.Generic;

using System.Globalization;

using System.Linq;

using System.Xml.Linq;

using StockTraderRI.Infrastructure.Interfaces;

using StockTraderRI.Infrastructure.Models;

using StockTraderRI.Modules.News.Properties;

using System.ComponentModel.Composition;



namespace StockTraderRI.Modules.News.Services

{

    [Export(typeof(INewsFeedService))]

    [PartCreationPolicy(CreationPolicy.Shared)]

    public class NewsFeedService : INewsFeedService

    {

        readonly Dictionary<string, List<NewsArticle>> newsData = new Dictionary<string, List<NewsArticle>>();



        public NewsFeedService()

        {

            var document = XDocument.Parse(Resources.News);

            newsData = document.Descendants("NewsItem")

                .GroupBy(x => x.Attribute("TickerSymbol").Value,

                x => new NewsArticle

                {

                    PublishedDate = DateTime.Parse(x.Attribute("PublishedDate").Value, CultureInfo.InvariantCulture),

                    Title = x.Element("Title").Value,

                    Body = x.Element("Body").Value,

                    IconUri = x.Attribute("IconUri") != null ? x.Attribute("IconUri").Value : null

                })

                .ToDictionary(group => group.Key, group => group.ToList());

        }



        #region INewsFeed Members



        public IList<NewsArticle> GetNews(string tickerSymbol)

        {

            List<NewsArticle> articles = new List<NewsArticle>();

            newsData.TryGetValue(tickerSymbol, out articles);

            return articles;

        }



        public event EventHandler<NewsFeedEventArgs> Updated = delegate { };



        public bool HasNews(string tickerSymbol)

        {

            return newsData.ContainsKey(tickerSymbol);

        }



        #endregion

    }

}