MonoRail/Castle.MonoRail.ActiveRecordSupport/Pagination/ARPaginableCriteria.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.MonoRail.ActiveRecordSupport.Pagination
  16 {
  17         using System;
  18         using System.Collections;
  19
  20         using Castle.ActiveRecord;
  21         using Castle.ActiveRecord.Framework;
  22
  23         using NHibernate;
  24         using NHibernate.Expressions;
  25
  26         /// <summary>
  27         /// A paginable criteria.
  28         /// Mimics the <see cref="ActiveRecordMediator.FindAll(Type)"/> interface.
  29         /// </summary>
  30         public class ARPaginableCriteria : IARPaginableDataSource
  31         {
  32                 private Type targetType;
  33                 private ICriterion[] criterions;
  34                 private Order[] orders;
  35                 private DetachedCriteria detachedCriteria;
  36
  37                 private ICriteria cachedCriteria;
  38
  39                 private int pageSize, currentPage;
  40
  41                 public ARPaginableCriteria(Type targetType, Order[] orders, params ICriterion[] criterions)
  42                 {
  43                         this.targetType = targetType;
  44                         this.orders = orders;
  45                         this.criterions = criterions;
  46                 }
  47
  48                 public ARPaginableCriteria(Type targetType, params ICriterion[] criterions) : this(targetType, null, criterions) { }
  49
  50                 public ARPaginableCriteria(Type targetType, params Order[] orders) : this(targetType, orders, null) { }
  51
  52                 public ARPaginableCriteria(Type targetType, DetachedCriteria detachedCriteria) : this(targetType, null, (ICriterion[])null)
  53                 {
  54                         this.detachedCriteria = detachedCriteria;
  55                 }
  56
  57                 protected virtual ICriteria BuildCriteria(ISession session)
  58                 {
  59                         if (cachedCriteria == null)
  60                         {
  61                                 if (detachedCriteria != null)
  62                                 {
  63                                         cachedCriteria = detachedCriteria.GetExecutableCriteria(session);
  64                                 }
  65                                 else
  66                                 {
  67                                         cachedCriteria = session.CreateCriteria(targetType);
  68
  69                                         if (criterions != null)
  70                                         {
  71                                                 foreach (ICriterion queryCriteria in criterions)
  72                                                 {
  73                                                         cachedCriteria.Add(queryCriteria);
  74                                                 }
  75                                         }
  76                                 }
  77
  78                                 if (orders != null)
  79                                 {
  80                                         foreach (Order order in orders)
  81                                         {
  82                                                 cachedCriteria.AddOrder(order);
  83                                         }
  84                                 }
  85                         }
  86
  87                         return cachedCriteria;
  88                 }
  89
  90                 /// <summary>
  91                 /// Implementors should execute a query
  92                 /// to return the record count
  93                 /// </summary>
  94                 /// <remarks>
  95                 /// This needs a performance boost. Couldn't think of a better
  96                 /// way of get the count.
  97                 /// </remarks>
  98                 public virtual int ObtainCount()
  99                 {
 100                         ISessionFactoryHolder holder = ActiveRecordMediator.GetSessionFactoryHolder();
 101                         ISession session = holder.CreateSession(targetType);
 102
 103                         try
 104                         {
 105                                 ICriteria criteria = BuildCriteria(session);
 106
 107                                 return criteria.List().Count;
 108                         }
 109                         finally
 110                         {
 111                                 holder.ReleaseSession(session);
 112                         }
 113                 }
 114
 115                 public IEnumerable Paginate(int pageSize, int currentPage)
 116                 {
 117                         this.pageSize = pageSize;
 118                         this.currentPage = currentPage;
 119                         return InternalExecute(false);
 120                 }
 121
 122                 public IEnumerable ListAll()
 123                 {
 124                         return InternalExecute(true);
 125                 }
 126
 127                 private IEnumerable InternalExecute(bool skipPagination)
 128                 {
 129                         ISessionFactoryHolder holder = ActiveRecordMediator.GetSessionFactoryHolder();
 130                         ISession session = holder.CreateSession(targetType);
 131
 132                         try
 133                         {
 134                                 ICriteria criteria = BuildCriteria(session);
 135
 136                                 if (!skipPagination)
 137                                 {
 138                                         criteria.SetFirstResult(pageSize * (currentPage-1));
 139                                         criteria.SetMaxResults(pageSize);
 140                                 }
 141
 142                                 return criteria.List();
 143                         }
 144                         finally
 145                         {
 146                                 holder.ReleaseSession(session);
 147                         }
 148                 }
 149         }
 150 }