ClearCache aspect

RSS

The ClearCache attribute clears cached data for the provided method.

ClearCacheAspect.cs

using System;

using NUnit.Framework;

using BLToolkit.Aspects;
using BLToolkit.Reflection;

namespace HowTo.Aspects
{
    [TestFixture]
    public class ClearCacheAspect
    {
        public abstract class TestClass
        {
            public static int Value;

            // This is a method we will cache. Cached return value depends on input parameters.
            // We will change the 'Value' field outside of the class and see how it affects the result.
            //
            [Cache(MaxCacheTime=500, IsWeak=false)]
            public virtual int CachedMethod(int p1, int p2)
            {
                return Value;
            }

            // This method clears the CachedMethod cache.
            //
            [ClearCache("CachedMethod")]
            public abstract void ClearCache();

            // The CachedMethod is specified by name and parameters.
            // Also you can use declaring method type.
            //
            [ClearCache("CachedMethod", typeof(int), typeof(int))]
            public abstract void ClearCache2();

            // This method clears all caches for provided type.
            //
            [ClearCache(typeof(TestClass))]
            public abstract void ClearAll();

            // This method clears all caches for current type.
            //
            [ClearCache]
            public abstract void ClearAll2();

            public static TestClass CreateInstance()
            {
                // Use TypeAccessor to create an instance of an abstract class.
                //
                return TypeAccessor<TestClass>.CreateInstance();
            }
        }

        [Test]
        public void Test()
        {
            TestClass tc = TypeAccessor<TestClass>.CreateInstance();

            TestClass.Value = 1;

            int value1 = tc.CachedMethod(1, 2);

            TestClass.Value = 2;

            int value2 = tc.CachedMethod(1, 2);

            // The cached values are equal.
            //
            Assert.AreEqual(value1, value2);

            tc.ClearCache();

            TestClass.Value = 3;

            // Previous and returned values are not equal.
            //
            Assert.AreNotEqual(value1, tc.CachedMethod(1, 2));

            tc.ClearCache2();
        }
    }
}

BLToolkit type builder will generate the following for the class above:

[BLToolkitGenerated]
public sealed class TestClass : ClearCacheAspect.TestClass
{
    private static MethodInfo _methodInfo1;
    private static MethodInfo _methodInfo2;
    private static Type       _type3;
    private static Type       _type4;

    public override int CachedMethod(int p1, int p2)
    {
        // Method implementation.
    }

    public override void ClearCache()
    {
        try
        {
            // Here should be main method implementation.
            // It is empty as this method does nothing.
        }
        finally
        {
            if (_methodInfo1 == null)
            {
                _methodInfo1 = 
                    ClearCacheAspect.GetMethodInfo(this, null, "CachedMethod", null);
            }

            CacheAspect.ClearCache(_methodInfo1);
        }
    }

    public override void ClearCache2()
    {
        try
        {
        }
        finally
        {
            if (_methodInfo2 == null)
            {
                _methodInfo2 = ClearCacheAspect.GetMethodInfo(
                    this,
                    null,
                    "CachedMethod",
                    new Type[] { typeof(int), typeof(int) });
            }

            CacheAspect.ClearCache(_methodInfo2);
        }
    }

    public override void ClearAll()
    {
        try
        {
        }
        finally
        {
            if (_type3 == null)
            {
                _type3 = ClearCacheAspect.GetType(this, typeof(TestClass));
            }

            CacheAspect.ClearCache(_type3);
        }
    }

    public override void ClearAll2()
    {
        try
        {
        }
        finally
        {
            if (_type4 == null)
            {
                _type4 = ClearCacheAspect.GetType(this, null);
            }

            CacheAspect.ClearCache(_type4);
        }
    }
}