Zack Owens

Cache Abstraction

I'm in the middle of a project and I wrote my own Cache logic that melds nicely to my project's needs. But how do I test it? I can't mock the System.Web.Caching.Cache class. So I looked in the Abstractions that ship with ASP.NET MVC. What do you know, they're not there!

So I created my own base class and wrapper. Here's the code. Enjoy.

using System;
using System.Collections;
using System.Web.Caching;

namespace WebCommon.Abstractions
{
    public abstract class CacheBase : IEnumerable
    {
        public abstract int Count { get; }
        public abstract long EffectivePercentagePhysicalMemoryLimit { get; }
        public abstract long EffectivePrivateBytesLimit { get; }
        public abstract object this[string key] { get; set; }
        public abstract object Add(string key, object value, CacheDependency dependencies, DateTime absoluteExpiration, TimeSpan slidingExpiration, CacheItemPriority priority, CacheItemRemovedCallback onRemoveCallback);
        public abstract object Get(string key);
        public abstract IDictionaryEnumerator GetEnumerator();
        public abstract void Insert(string key, object value);
        public abstract void Insert(string key, object value, CacheDependency dependencies);
        public abstract void Insert(string key, object value, CacheDependency dependencies, DateTime absoluteExpiration, TimeSpan slidingExpiration);
        public abstract void Insert(string key, object value, CacheDependency dependencies, DateTime absoluteExpiration, TimeSpan slidingExpiration, CacheItemPriority priority, CacheItemRemovedCallback onRemoveCallback);
        public abstract object Remove(string key);

        IEnumerator IEnumerable.GetEnumerator()
        {
            return this.GetEnumerator();
        }
    }
}

using System;
using System.Collections;
using System.Web.Caching;

namespace WebCommon.Abstractions
{
    public class CacheWrapper : CacheBase
    {
        private Cache _cache;

        public CacheWrapper(Cache cache)
        {
            _cache = cache;
        }

        public override int Count
        {
            get { return _cache.Count; }
        }

        public override long EffectivePercentagePhysicalMemoryLimit
        {
            get { return _cache.EffectivePercentagePhysicalMemoryLimit; }
        }

        public override long EffectivePrivateBytesLimit
        {
            get { return _cache.EffectivePrivateBytesLimit; }
        }

        public override object this[string key]
        {
            get
            {
                return _cache[key];
            }
            set
            {
                _cache[key] = value;
            }
        }

        public override object Add(string key, object value, CacheDependency dependencies, DateTime absoluteExpiration, TimeSpan slidingExpiration, CacheItemPriority priority, CacheItemRemovedCallback onRemoveCallback)
        {
            return _cache.Add(key, value, dependencies, absoluteExpiration, slidingExpiration, priority, onRemoveCallback);
        }

        public override object Get(string key)
        {
            return _cache.Get(key);
        }

        public override IDictionaryEnumerator GetEnumerator()
        {
            return _cache.GetEnumerator();
        }

        public override void Insert(string key, object value)
        {
            _cache.Insert(key, value);
        }

        public override void Insert(string key, object value, CacheDependency dependencies)
        {
            _cache.Insert(key, value, dependencies);
        }

        public override void Insert(string key, object value, CacheDependency dependencies, DateTime absoluteExpiration, TimeSpan slidingExpiration)
        {
            _cache.Insert(key, value, dependencies, absoluteExpiration, slidingExpiration);
        }

        public override void Insert(string key, object value, CacheDependency dependencies, DateTime absoluteExpiration, TimeSpan slidingExpiration, CacheItemPriority priority, CacheItemRemovedCallback onRemoveCallback)
        {
            _cache.Insert(key, value, dependencies, absoluteExpiration, slidingExpiration, priority, onRemoveCallback);
        }

        public override object Remove(string key)
        {
            return _cache.Remove(key);
        }
    }
}