Enterprise Library 3 Policy Injection Application Block Example

From 1 year I am interesting about AOP.I tried Spring.NET and now I am using new features of MS Enterprise Library 3.x.

Here I am posting some code  that uses new Policy Injection Application Block built in Enterprise Library 3.x. I begin from business objects arriving to Factories calls. It  is an example similar to the one in slides from Microsoft and it is about caching.

public class HTMLContentDataProvider : DataProviderTransactableBase, IHTMLContentDataProvider

[CachingCallHandler(2, 0, 0)]

HTMLContentLocalesDictionary objs = new HTMLContentLocalesDictionary();

using (DbCommand c = this.CurrentDatabase.GetSqlStringCommand("SELECT * FROM HTMLContents WHERE HTMC_TopicId=@id"))

{

CurrentDatabase.AddInParameter(c, "id", DbType.Int32, topicId);

IDataReader dr = this.CurrentDatabase.ExecuteReader(c);

using (dr) {

while (dr.Read()) {

HTMLContent tmp = BuildHTMLContenteFromDataRow(dr);

if(!objs.ContainsKey(tmp.Language.Trim()))

objs.Add(tmp.Language.Trim(),tmp);

}

}

return objs;

}

...................

This is the object where I want to inject caching policy.I used an attribute where I say that I want to cache content for 2 hours. For every method I can apply some policies by attribute or using configuration and matching rules. Base class DataProviderTransactableBase inherits from MarshalByRefObject. This permits to create a proxy object that is a placeholder for apply our policies.

public class DataProviderTransactableBase : MarshalByRefObject

HTMLContentDataProvider obj = PolicyInjection.Create<HTMLContentDataProvider>();