NCache API Caching

After successfully configuring NCache, you can start developing the application by embedding NCache API calls. NCache client applications can communicate with the cache servers through InitializeCache method. This method establishes connection between client and server and returns a cache handle. This cache handle can then be further used for Add, Insert, Get, Remove and other cache operations.

Let's quickly create a console .NET application to demonstrate the use of NCache.

Pre-requisites

• Launch Visual Studio 2010+ for .NET Framework.

• Create a new Console Application for .NET Framework.

• For NCache OpenSource Edition, install the NuGet package Alachisoft.NCache.OpenSource.SDK on Package Manager Console as following:

Install-Package Alachisoft.NCache.OpenSource.SDK -Version 4.6.3

Ensure Data is Serialized

Whether you are using NCache for ASP.NET Sessions or for object caching, you must ensure that all .NET objects are serializable.

Select "Add->Class" menu from Solutions to create a new class Product as following:

[Serializable]
public class Product
{
  public int ProductID { get; set; }
  public string ProductName { get; set; }
  public string Category { get; set; }
  public int UnitsInStock { get; set; }
}

Initialize Cache

After you have configured the cache, embed NCache API calls in your application. The first thing you need to do is to initialize the cache with name of the cache you created in Create Cache.

//Initialize the cache
Cache cache = NCache.InitializeCache("demoClusteredCache");

Add Data

In order to add data to cache, it must be ensured that the object is either .NET serialized. In this example, a new object of Product class is created and added to cache.

Product product = new Product();
product.ProductID = 1001;
product.ProductName = "Chai";
product.UnitsInStock = 15;
product.Category = "Beverages";

string key = "Product:" + product.ProductID;

try
{
    cache.Add(key, product);
}
catch (OperationFailedException ex)
{
    // Handle exception
    // usually thrown if key already exists in cache
    // however verify the failure reason
}

Insert Data

Similarly, in order to update data previously added in cache, it must be ensured that the object is serialized. In this example, a new object is added with an existing key.

Product product = new Product();
product.ProductID = 1001;
product.ProductName = "Chai";
product.UnitsInStock = 5; // updated units
product.Category = "Beverages";

string key = "Product:" + product.ProductID;

try
{
    // Precondition: Cache is already initialized and item exists
    cache.Insert(key, product);
}
catch (OperationFailedException ex)
{
    // Handle exception
}

Remove Data

NCache provides two methods (remove, delete) to delete an object from the cache.

Delete Method	Remove Method
Returns void after deletion.	Deletes data from the cache and returns status to the application.

Using Remove Method

Remove removes the key from the cache and returns the removed object to the cache.

string key = "Product:1001";

Product product = null;

try
{
    // Null is returned if key does not exist in cache
    object result = cache.Remove(key);

    if (result != null)
    {
        if (result is Product)
        {
            product = (Product)result;
        }
    }
}
catch (OperationFailedException ex)
{
    // Handle exception
}

Using Delete Method

Delete deletes the key from the cache without returning the object.

string key = "Product:1001";

try
{
    cache.Delete(key);
}
catch (OperationFailedException ex)
{
    // Handle exception
}

Get Data

Get method is used to retrieve item Product:1001. This item has previously been added to the cache. Get method returns general object which needs to be cast accordingly. If a key does not exist in cache, null value is returned.

string key = "Product:1001";

Product product = null;

try
{
    // Null is returned if key does not exist in the cache
    object result = cache.Get(key);

    if (result != null)
    {
        if (result is Product)
        {  
            product = (Product)result;
        }
    }
}
catch (OperationFailedException ex)
{
    // Handle exception
}

Dispose Cache

After you are done using the cache, you should dispose it in order to free the resources being used up by the cache.

Cache cache = NCache.InitializeCache("demoClusteredCache");

// Dispose the cache
cache.Dispose();