Add/Update Cache Data with Groups
Note
This feature is only available in NCache Enterprise Edition.
NCache allows the user to add an item in the cache with a certain group. There can only be a single item associated with a single group.
CacheItem
is a custom class provided by NCache which can be used to add data to the cache. CacheItem
also lets you set
additional specifications associated with an object as a property
of groups.
CacheItem
is added in the cache using the Insert
method, a recommended approach with group if no item already exists in the cache with the specified key.
Whereas the Add
operation fails if the key already exists and an exception will be thrown.
Prerequisites
In the following example, data group is set by assigning it as a property of CacheItem
containing the object customer.
try
{
// Pre-conditions: Cache is already connected
/*In an online-store, customers from different regions need to be grouped accordingly
A customer has signed in to the website from the East Coast region*/
// Create a unique cache key for this customer.
string customerKey = $"Customer:ALFKI";
// Get customer from cache
Customer customer = cache.Get<Customer>(customerKey);
// Get customer from database if not found in cache
if (customer == null)
{
customer = FetchCustomerFromDB("ALFKI");
// Create a new CacheItem
var cacheItem = new CacheItem(customer);
// Specify the group
cacheItem.Group = "East Coast Customers";
// Add customer object to cache with group
cache.Add(customerKey, cacheItem);
}
}
catch (OperationFailedException ex)
{
// Exception can occur due to:
// Connection Failures
// Operation Timeout
// Operation performed during state transfer
}
catch (Exception ex)
{
// Any generic exception like ArgumentNullException or ArgumentException
}
try
{
// Pre-condition: Cache is already connected
// Get customer from database against given customer ID
Customer customer = fetchCustomerFromDB("ALFKI");
// Create a unique cache key for this customer
String key = "Customer:" + customer.getCustomerID();
// Create a new CacheItem
CacheItem cacheItem = new CacheItem(customer);
// Specify the group
cacheItem.setGroup("ImportantCustomers");
// Add customer object to cache with group
CacheItemVersion version = cache.insert(key, cacheItem);
// cacheItem is successfully added in the cache with group
}
catch (Exception ex)
{
// Exception can occur due to:
// Connection Failures
// Operation Timeout
// Operation performed during state transfer
// Any generic exception
}
try {
// Pre-condition: Cache is already connected
// Get customer from database against given customer ID
val customer = fetchCustomerFromDB("ALFKI")
// Create a unique cache key for this customer
val key = "Customer:" + customer.getCustomerId
// Create a new CacheItem
val cacheItem = new CacheItem(customer)
// Specify the group
cacheItem.setGroup("ImportantCustomers")
// Add customer object to cache with group
val version = cache.insert(key, cacheItem)
// cacheItem is successfully added in the cache with group
}
catch {
case exception: Exception => {
// Handle any errors
}
}
// This is an async method
try
{
// Pre-condition: Cache is already connected
// Get customer from database against given customer ID
var customer = this.fetchCustomerFromDB("ALFKI");
// Create a unique cache key for this customer.
var key = "Customers:" + customer.getCustomerID();
// Create a new CacheItem
var cacheItem = new ncache.CacheItem(customer);
// Specify the group
cacheItem.setGroup("Important Customers");
// Add customer object to cache with group
var version = await this.cache.insert(key, cacheItem);
// cacheItem is successfully added in the cache with group
}
catch(error)
{
// Handle errors
}
try:
# Pre-condition: Cache is already connected
# Get customer from database
customer = fetch_customer_from_db()
# Create a unique cache key for this customer.
key = "Customers:" + customer.get_customer_id()
# Create a new CacheItem
cache_item = ncache.CacheItem(customer)
# Specify the group
cache_item.set_group("Important Customers")
# Add customer object to cache with group
version = cache.insert(key, cache_item)
# CacheItem is successfully added in the cache with group
except Exception as exp:
# Handle errors
Note
To ensure the operation is fail-safe, it is recommended to handle any potential exceptions within your application, as explained in Handling Failures.
Update Group of a CacheItem
The data group of a CacheItem
can also be updated. A CacheItem
is a custom class provided by NCache which can be used to add data to the cache. The CacheItem
also lets you set the group as a property
of the CacheItem
.
The following example updates group in a CacheItem
.
// A customer has signed in to the website from a different region i.e. West Coast
string customerKey = $"Customer:ALFKI";
// Retrieve the cacheItem from the cache
var cacheItem = cache.GetCacheItem(customerKey);
// Specify the new group to be updated
cacheItem.Group = "West Coast Customers";
// Reinsert the cacheItem in the cache with updated groups
cache.Insert(customerKey, cacheItem);
// Pre-condtion: CacheItem is added with the group
// Get customer from database against given customer ID
Customer customer = fetchCustomerFromDB(1000);
// Create a unique cache key for this customer.
String key = "Customer:" + customer.getCustomerID();
//Retrieve cache item from cache
CacheItem cacheItem = cache.getCacheItem(key);
// Specify the new group to be updated
cacheItem.setGroup("US Customers");
// Re-insert the cacheItem in the cache with updated groups
cache.insert(key, cacheItem);
// CacheItem is successfully added in the cache with updated group
// Pre-condition: CacheItem is added with the group
// Get customer from database against given customer ID
val customer = fetchCustomerFromDB(1000)
// Create a unique cache key for this customer.
val key = "Customer:" + customer.getCustomerId
//Retrieve cache item from cache
val cacheItem = cache.getCacheItem(key)
// Specify the new group to be updated
cacheItem.setGroup("US Customers")
// Re-insert the cacheItem in the cache with updated groups
cache.insert(key, cacheItem)
// CacheItem is successfully added in the cache with updated group
// This is an async method
// Pre-condtion: CacheItem is added with the group
// Retrieve the cacheItem from the cache
var key = "ALFKI";
var cacheItem = this.cache.getCacheItem(key);
// Re-insert the item in the cache after the removal of group
await this.cache.insert(key, cacheItem);
// Get cacheitem with the updated version
cacheItem = this.cache.getCacheItem(key);
// Specify the new group to be updated
cacheItem.setGroup("US Customers");
// Re-insert the cacheItem in the cache with updated groups
await this.cache.insert(key, cacheItem);
// CacheItem is successfully added in the cache with updated group
# Pre-condition: CacheItem is added with the group
# Retrieve the CacheItem with old group from the cache
key = "ALFKI"
cache_item = cache.get_cacheitem(key)
# Specify the new group to be updated
cache_item.set_group("US Customers")
# Re-insert the cacheItem in the cache with updated groups
cache.insert(key, cache_item)
# CacheItem is successfully added in the cache with updated group
Additional Resources
NCache provides a sample application for Groups on GitHub.
See Also
Retrieve Cache Data with Groups
Remove Cache Data with Group
Basic Operations for Caching Data
Tag Cache Data