Attribute活用
Attribute自作
using System.Runtime.Remoting.Contexts;
using System.Runtime.Remoting.Messaging;
[AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
public sealed class MyInterceptorAttribute
: ContextAttribute, IContributeObjectSink
{
public MyInterceptorAttribute()
: base("MyInterceptor") { }
// IContributeObjectSinkのメソッド実装
public IMessageSink GetObjectSink(
MarshalByRefObject obj, IMessageSink next)
{
return new MyAopHandler(next);
}
}
[AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
public sealed class MyInterceptorMethodAttribute : Attribute { }
AOPコア
public class MyAopHandler : IMessageSink
{
private IMessageSink nextSink;
public IMessageSink NextSink
{
get { return this.nextSink; }
}
public MyAopHandler(IMessageSink nextSink)
{
this.nextSink = nextSink;
}
// 同期
public IMessage SyncProcessMessage(IMessage msg)
{
IMessage retMsg = null;
IMethodCallMessage call = msg as IMethodCallMessage;
if (call == null || (Attribute.GetCustomAttribute(call.MethodBase, typeof(MyInterceptorMethodAttribute))) == null)
{
retMsg = this.nextSink.SyncProcessMessage(msg);
}
else
{
Console.WriteLine("before");
retMsg = this.nextSink.SyncProcessMessage(msg);
Console.WriteLine("after");
}
return retMsg;
}
// 非同期
public IMessageCtrl AsyncProcessMessage(
IMessage msg, IMessageSink replySink)
{
return null;
}
}
利用側
[MyInterceptor]
public class BusinessHandler : ContextBoundObject
{
[MyInterceptorMethod]
public void DoSomething()
{
Console.WriteLine("test");
}
}
var handler = new BusinessHandler();
handler.DoSomething();