static void Main(string[] args)
{
var newsSource = new GoogleNewsSource();
var adSource = new AdvertisementSource();
var newsAgency = new MyNewsAgency(newsSource, adSource);
//Example demoing push model of Observable pattern
//The news source would publish/push this news to all it's subscribers
newsSource.PublishNews(new News {
Headline = "Microsoft jumping into gaming space", Priority = Priority.Low, Category = NewsCategory.Technical, Content = "A good news for gaming enthusiasts as Microsoft to soon launch a new gaming platform."
});
var newsPaper = newsAgency.CompileNewsPaper();
Console.WriteLine("--------------" + newsPaper.Name + "-" + newsPaper.Date.ToShortDateString() + "-----------------");
int pageNumber = 1;
foreach (var page in newsPaper.Pages)
{
Console.WriteLine("-----Page -" + pageNumber + "--------");
foreach (var news in page.NewsArticles)
{
Console.WriteLine(news.Headline);
Console.WriteLine(news.Content);
Console.WriteLine("-----------------------------------");
}
Console.WriteLine("----------Advertisements Section-------------------");
foreach (var add in page.Advertisements)
{
Console.WriteLine(add.Product);
Console.WriteLine(add.AdContent);
Console.WriteLine("-----------------------------------");
}
pageNumber++;
}
Console.ReadLine();
}
public NewsPaper CompileNewsPaper()
{
//Step 1. Fetch all the news from the news source.(This demos the pull mode of the publis-subscribe/observable pattern)
var newsItems = NewsSource.FetchNews(subscriberId);
if (newsItems == null || newsItems.Count() <= 0)
{
throw new Exception("No news items returned from the news source");
}
NewsItems.AddRange(newsItems.OrderBy(n => n.Priority));
//Step 1.1 Fetch all the ads
var adds = AdvertisementSource.GetAdds().ToArray();
//Step 2. Start Compiling newspaper for the fetched news and ads
var newsPaper = new NewsPaper
{
Name = "The News Express",
Date = DateTime.Now.Date,
Pages = new List <Page>()
};
Page page = new Page();
newsPaper.Pages.Add(page);
int advertisementEnumerator = 0;
foreach (var news in NewsItems)
{
if (IsPageFull(page))
{
page = new Page();
newsPaper.Pages.Add(page);
}
if (page.NewsArticles.Count < maxNewsItemsOnPage)
{
page.NewsArticles.Add(news);
}
else //max news items added to page, now we can accomodate advertisements
{
//Keep adding advertisements to the page till page is full
while (!IsPageFull(page) && advertisementEnumerator < adds.Count())
{
page.Advertisements.Add(adds[advertisementEnumerator]);
advertisementEnumerator++;
}
//Create new page if after adding advertisements, the page is full, else add news to the same page
if (IsPageFull(page))
{
page = new Page();
newsPaper.Pages.Add(page);
page.NewsArticles.Add(news);
}
else
{
page.NewsArticles.Add(news);
}
}
}
//There are still some adds to be placed on the pages
if (advertisementEnumerator < adds.Count())
{
while (advertisementEnumerator < adds.Count())
{
var lastPage = newsPaper.Pages.LastOrDefault();
if (!IsPageFull(lastPage))
{
lastPage.Advertisements.Add(adds[advertisementEnumerator]);
advertisementEnumerator++;
}
else
{
var newPage = new Page();
newsPaper.Pages.Add(newPage);
newPage.Advertisements.Add(adds[advertisementEnumerator]);
advertisementEnumerator++;
}
}
}
return(newsPaper);
}
