AggregateProjection.cs

using System;
using NHibernate.SqlCommand;
using NHibernate.Type;

namespace NHibernate.Expression
{
	/// <summary>
	/// An Aggregation
	/// </summary>
	[Serializable]
	public class AggregateProjection : SimpleProjection
	{
		protected readonly string propertyName;
		protected readonly string aggregate;

		protected internal AggregateProjection(string aggregate, string propertyName)
		{
			this.aggregate = aggregate;
			this.propertyName = propertyName;
		}

		public override string ToString()
		{
			return aggregate + "(" + propertyName + ')';
		}

		public override IType[] GetTypes(ICriteria criteria, ICriteriaQuery criteriaQuery)
		{
			return new IType[] {criteriaQuery.GetType(criteria, propertyName)};
		}

		public override SqlString ToSqlString(ICriteria criteria, int loc, ICriteriaQuery criteriaQuery)
		{
			return new SqlString(new object[]
			                     	{
			                     		aggregate,
			                     		"(",
			                     		criteriaQuery.GetColumn(criteria, propertyName),
			                     		") as y",
			                     		loc.ToString(),
			                     		"_"
			                     	});
		}
	}
}