Configure Invalidation Attributes for Data Structures in Cache

Note

This feature is only available in NCache Enterprise Edition.

Data Structures can be invalidated from the cache using:

Expiration
Eviction
Dependency

These attributes are specified during data type creation using the DataTypeAttributes class, and can not be modified once a data type is created in cache. Moreover, these invalidation attributes can be specified against all data structures.

Note

Key dependencies can be configured between CacheItem and Data Structures as well.

Pre-requisites

Include the following namespaces in your application:
- Alachisoft.NCache.Client.DataTypes
- Alachisoft.NCache.Client
- Alachisoft.NCache.Runtime.Exceptions
- Alachisoft.NCache.Runtime
- Alachisoft.NCache.Runtime.Caching
The application must be connected to cache before performing the operation.
Cache must be running.
To ensure the operation is fail safe, it is recommended to handle any potential exceptions within your application, as explained in Handling Failures.

The following code sample creates a set OrderIDSet which is dependent on a Product object in cache. OrderList is assigned an expiration value of 15 minutes and its priority is set to high. If the Product is modified in cache, OrderIDSet is removed from cache.

try
{
    // Pre-conditions: Cache must be connected
    // Product exists in cache with key "Product:1001"

    // Product with this key exists in cache
    string productKey = "Product:1001";

    // Specify attributes for hashset
    var attributes = new DataTypeAttributes();

    // Specifiy priority for eviciton
    attributes.Priority = CacheItemPriority.High;

    // Specify Absolute expiration of 15 minutes
    var expiration = new Expiration(ExpirationType.Absolute, TimeSpan.FromMinutes(15));
    attributes.Expiration = expiration;

    // Specify key dependency of orderKey on customerKey
    var keyDependency = new KeyDependency(productKey);
    attributes.Dependency = keyDependency;

    // Create hashset which is dependent on product:1001
    // Specify unique cache key for set
    string orderKey = "OrderIDSet";

    IDistributedHashSet<int> orderIDSet = 
                cache.DataTypeManager.CreateHashSet<int>(orderKey, attributes);

    // Check if the orderIDSet exists in cache:
    // After 15 minutes or
    // If product is modified in cache
}
catch (OperationFailedException ex)
{
    // NCache specific exception
    if(ex.ErrorCode == NCacheErrorCodes.KEY_ALREADY_EXISTS)
    {       
        // An item with the same key already exists
    }
    else if (ex.ErrorCode == NCacheErrorCodes.CACHEITEM_IN_DATA_STRUCTURES)
    {
        // Data structures cannot be of CacheItem type
        // CacheItems cannot be added in data structures
    }
    else
    {
        // NCache specific exception
        // Exception can occur due to:
        // Connection Failures
        // Operation Timeout
        // Operation performed during state transfer
    }
}
catch (Exception ex)
{
    // Any generic exception like ArgumentNullException or ArgumentException
}

Configure Invalidation Attributes for Data Structures in Cache

Note

Note

Pre-requisites

See Also