C# Generic Cache Manager Example
This examples shows how to implement a generic cache manager class in C#. We often need to cache to the some objects in our programs, ecpecially for objects that frequently access. Following sample is implemented for this purpose.
Usage:
CacheManager<string> cm = new CacheManager<string>(); //keep this instance in a class
cm.Add("key1", "data1", 5000); //remove after 5 sc
cm.Add("key2", "data2"); //don't remove from cache
cm.Add("key3", "data3", 3000); //remove after 3 sc
cm.Add("key4", "data4"); //don't remove from cache
Also if we want to use only one cache manager instance, we can use Singleton Pattern in Design Patterns.
For more information about Singleton Pattern:
https://csharpexamples.com/c-multithread-singleton-pattern-example
Generic Cache Manager Class:
public class CacheManager<T>
{
private Dictionary<string, T> _items = null;
public CacheManager()
{
_items = new Dictionary<string, T>();
}
private void TimerProc(object state)
{
//Remove the cached object
string key = state.ToString();
this.Remove(key);
}
public void Add(string key, T obj, int cacheTime = System.Threading.Timeout.Infinite)
{
if (string.IsNullOrEmpty(key))
throw new ArgumentNullException("key is null.");
if (_items.Keys.Contains(key))
throw new ArgumentException("An element with the same key already exists.");
//Set timer
System.Threading.Timer t = new System.Threading.Timer(new TimerCallback(TimerProc),
key,
cacheTime,
System.Threading.Timeout.Infinite);
_items.Add(key, obj);
}
public bool Remove(string key)
{
if (string.IsNullOrEmpty(key))
throw new ArgumentNullException("key is null.");
return _items.Remove(key);
}
public T Get(string key)
{
if (string.IsNullOrEmpty(key))
throw new ArgumentNullException("key is null.");
if (!_items.Keys.Contains(key))
throw new KeyNotFoundException("key does not exist in the collection.");
return _items[key];
}
public void Clear()
{
_items.Clear();
}
}
