Cross cutting concerns (wiki) are common architectural elements such as logging, instrumentation, caching and transactions. In this article, we will explain how we integrate these into our projects. The functional classes in our project may use logging or caching within their method. Or they may not know that these other classes exist. We will cover both scenarios.
Decorator pattern is an elegant solution to implement cross-cutting concerns.…
Dijkstra’s algorithm computes the shortest distance between two vertices in a graph. Vertices in a graph are connected by an edge with a positive length.
static int SingleSourceShortestPathForNonNegativeEdgeLength(Vertex v)
{
int min = short.MaxValue;
var crossingEdges = new MinHeap<short, short>(N);
var minVertices = new bool[N];
minVertices[v.Id - 1] = true;
foreach (var outgoingEdge in v.OutgoingEdges)
{
// Use a Heapify operation!… Over the weekend, I ran the Bellman Ford algorithm (All Pair Shortest Path). The algorithm has a running time of O(n2m). There were 20,000 nodes in the graph. And it was pretty dense or more inter-connected. The program ran for four hours with a CPU load of 100% on a quad-core processor.
I noticed a significant degradation in performance due to Page faults within the application.…
Debugging a class library in a web application is pretty simple. But, this is something that can be tricky when you are joining a new organization or project.
If you do not know how to debug a class library in a web application, here are the steps:
A heap is a balanced tree which has some special properties. There are two variations of heap: MinHeap and MaxHeap. In a MinHeap, the root node is lesser than all the child nodes. MaxHeap has the maximum value in the root node.
Heap is not available in the .NET framework. The best implementation that I could find for a MinHeap is a blog post from Allan.…
The Introduction to FAST Search API provides an introduction on how to use the FAST API. FAST stores documents in a collection. We usually perform searches on a collection. But there are times when we want all documents in a collection. This article explains how.
The maximum number of documents in a FAST response is 4020. We page through the results, 100 documents at a time.…
QuickSelect is a selection algorithm that finds the kth smallest number from a list. QuickSelect is O(n) algorithm. I built a simple prototype to verify that QuickSelect works in linear time.
QuickSelect uses a random pivot to partition the array. The items to the left of the pivot are lesser than the pivot. The items to the right of the pivot are greater than the pivot. …
Knockout provides an elegant way of updating the user interface using Javascript View models. Javascript has an inheritance model. With that, we can create a hierarchy of classes. Consider the following HTML with Knockout bindings.
<div id="main">
<div data-bind="text: name"></div>
<div data-bind="text: detail"></div>
</div>
We use a simple Model class. Load it with data. And bind it to the HTML.
var model = new Model(); model.load();…
FAST is a search engine used for enterprise search. In FAST, a View specifies how content is structured. It has collections. A collection has documents. Each document has a specific structure, specified by fields.
Apart from specifying the content, a View has certain parameters to fine-tune the search. For example, parameters like lemmatisation and spell-check control the results returned by a search.…
The typical way to access a REST API is using the HttpClient. Create a HttpClient object. Pass in request headers. Call the PostAsync method with the URL and the request body. Use await keyword to wait for the response. Get the message as a JSON string. Use JavaScriptSerializer to convert the JSON to a C# object.
async Task<int> GetResultUsingHttpClient()
{
Uri uri = new Uri("http://localhost/api/Algebra
/DoAlgebra?num1=3&num2=4");…