ActiveRecord/Castle.ActiveRecord/Framework/Queries/ScalarQuery.Generic.cs

   1 // Copyright 2004-2008 Castle Project - http://www.castleproject.org/
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //     http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 namespace Castle.ActiveRecord.Queries
  16 {
  17         using System;
  18
  19         using NHibernate;
  20
  21         /// <summary>
  22         /// Represents a query that can result in a value
  23         /// of the type <typeparamref name="T"/>.
  24         /// </summary>
  25         /// <typeparam name="T">The resulting object type</typeparam>
  26         /// <remarks>
  27         /// If the query result is null, and <typeparamref name="T"/> is a value type,
  28         /// the default value for that type will be returned.
  29         /// </remarks>
  30         public class ScalarQuery<T> : ScalarQuery, IActiveRecordQuery<T>
  31         {
  32                 #region Constructors
  33                 /// <summary>
  34                 /// Creates a new <c>ScalarQuery</c> for the giving <paramref name="query"/>,
  35                 /// using the specified positional <paramref name="positionalParameters"/> and
  36                 /// the target ActiveRecord type specified in <paramref name="targetType"/>.
  37                 /// </summary>
  38                 /// <param name="targetType">The target ActiveRecord type</param>
  39                 /// <param name="query">The query</param>
  40                 /// <param name="positionalParameters">The positional positionalParameters</param>
  41                 public ScalarQuery(Type targetType, String query, params Object[] positionalParameters)
  42                         : base(targetType, query, positionalParameters)
  43                 {
  44                 }
  45
  46                 /// <summary>
  47                 /// Creates a new <c>ScalarQuery</c> for the giving <paramref name="query"/> and
  48                 /// the target ActiveRecord type specified in <paramref name="targetType"/>.
  49                 /// </summary>
  50                 /// <param name="targetType">The target ActiveRecord type</param>
  51                 /// <param name="query">The query</param>
  52                 public ScalarQuery(Type targetType, String query)
  53                         : base(targetType, query)
  54                 {
  55                 }
  56
  57                 /// <summary>
  58                 /// Creates a new <c>ScalarQuery</c> for the giving <paramref name="query"/>,
  59                 /// using the specified positional <paramref name="positionalParameters"/> and
  60                 /// the target ActiveRecord type specified in <paramref name="targetType"/>.
  61                 /// </summary>
  62                 /// <param name="targetType">The target ActiveRecord type</param>
  63                 /// <param name="queryLanguage">The language of the query</param>
  64                 /// <param name="query">The query</param>
  65                 /// <param name="positionalParameters">The positional positionalParameters</param>
  66                 public ScalarQuery(Type targetType, QueryLanguage queryLanguage, String query, params Object[] positionalParameters)
  67                         : base(targetType, queryLanguage, query, positionalParameters)
  68                 {
  69                 }
  70
  71                 /// <summary>
  72                 /// Creates a new <c>ScalarQuery</c> for the giving <paramref name="query"/> and
  73                 /// the target ActiveRecord type specified in <paramref name="targetType"/>.
  74                 /// </summary>
  75                 /// <param name="targetType">The target ActiveRecord type</param>
  76                 /// <param name="queryLanguage">The language of the query</param>
  77                 /// <param name="query">The query</param>
  78                 public ScalarQuery(Type targetType, QueryLanguage queryLanguage, String query)
  79                         : base(targetType, queryLanguage, query)
  80                 {
  81                 }
  82                 #endregion
  83
  84                 #region IActiveRecordQuery<T> implementation
  85                 T IActiveRecordQuery<T>.Execute(ISession session)
  86                 {
  87                         object result = InternalExecute(session);
  88                         return result == null ? default(T) : (T)result;
  89                 }
  90                 #endregion
  91
  92                 /// <summary>
  93                 /// Executes the query and gets the result.
  94                 /// </summary>
  95                 public T Execute()
  96                 {
  97                         object result = ActiveRecordMediator.ExecuteQuery(this);
  98                         return result == null ? default(T) : (T) result;
  99                 }
 100         }
 101 }