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

   1 // Copyright 2004-2007 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         using System.Collections;
  19
  20         using NHibernate;
  21
  22         /// <summary>
  23         /// Query that return a single result
  24         /// </summary>
  25         public class ScalarQuery : HqlBasedQuery
  26         {
  27                 #region Constructors
  28
  29                 /// <summary>
  30                 /// Initializes a new instance of the <see cref="ScalarQuery"/> class.
  31                 /// </summary>
  32                 /// <param name="targetType">Type of the target.</param>
  33                 /// <param name="query">The query.</param>
  34                 /// <param name="positionalParameters">The positional parameters.</param>
  35                 public ScalarQuery(Type targetType, string query, params Object[] positionalParameters)
  36                         : base(targetType, query, positionalParameters)
  37                 {
  38                 }
  39
  40                 /// <summary>
  41                 /// Initializes a new instance of the <see cref="ScalarQuery"/> class.
  42                 /// </summary>
  43                 /// <param name="targetType">Type of the target.</param>
  44                 /// <param name="query">The query.</param>
  45                 public ScalarQuery(Type targetType, string query)
  46                         : base(targetType, query)
  47                 {
  48                 }
  49
  50                 /// <summary>
  51                 /// Initializes a new instance of the <see cref="ScalarQuery"/> class.
  52                 /// </summary>
  53                 /// <param name="targetType">Type of the target.</param>
  54                 /// <param name="queryLanguage">The query language.</param>
  55                 /// <param name="query">The query.</param>
  56                 /// <param name="positionalParameters">The positional parameters.</param>
  57                 public ScalarQuery(Type targetType, QueryLanguage queryLanguage, string query, params Object[] positionalParameters)
  58                         : base(targetType, queryLanguage, query, positionalParameters)
  59                 {
  60                 }
  61
  62                 /// <summary>
  63                 /// Initializes a new instance of the <see cref="ScalarQuery"/> class.
  64                 /// </summary>
  65                 /// <param name="targetType">Type of the target.</param>
  66                 /// <param name="queryLanguage">The query language.</param>
  67                 /// <param name="query">The query.</param>
  68                 public ScalarQuery(Type targetType, QueryLanguage queryLanguage, string query)
  69                         : base(targetType, queryLanguage, query)
  70                 {
  71                 }
  72
  73                 #endregion
  74
  75                 /// <summary>
  76                 /// Executes the query and returns its scalar result.
  77                 /// </summary>
  78                 /// <param name="session">The NHibernate's <see cref="ISession"/></param>
  79                 /// <returns>The query's scalar result</returns>
  80                 protected override object InternalExecute(ISession session)
  81                 {
  82                         return CreateQuery(session).UniqueResult();
  83                 }
  84
  85                 /// <summary>
  86                 /// Creates a single-position object array containing
  87                 /// the query's scalar result.
  88                 /// </summary>
  89                 /// <param name="session">The NHibernate's <see cref="ISession"/></param>
  90                 /// <returns>An <c>object[1]</c> containing the query's scalar result.</returns>
  91                 protected override IEnumerable InternalEnumerate(ISession session)
  92                 {
  93                         return new Object[] { InternalExecute(session) };
  94                 }
  95         }
  96 }