1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2008 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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4 | *
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5 | * This file is part of HeuristicLab.
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6 | *
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7 | * HeuristicLab is free software: you can redistribute it and/or modify
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8 | * it under the terms of the GNU General Public License as published by
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9 | * the Free Software Foundation, either version 3 of the License, or
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10 | * (at your option) any later version.
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11 | *
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12 | * HeuristicLab is distributed in the hope that it will be useful,
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 | * GNU General Public License for more details.
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16 | *
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17 | * You should have received a copy of the GNU General Public License
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18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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19 | */
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20 | #endregion
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21 |
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22 | using System;
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23 | using System.Collections.Generic;
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24 | using System.Text;
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25 | using System.Data;
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26 | using System.Threading;
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27 | using HeuristicLab.DataAccess.Interfaces;
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28 |
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29 | namespace HeuristicLab.DataAccess.ADOHelper {
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30 | public abstract class CachedDataAdapter<AdapterT, ObjT, RowT, CacheT> :
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31 | DataAdapterBase<AdapterT, ObjT, RowT>,
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32 | ICachedDataAdapter
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33 | where CacheT : System.Data.TypedTableBase<RowT>, new()
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34 | where AdapterT : new()
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35 | where RowT : System.Data.DataRow
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36 | where ObjT : IPersistableObject, new() {
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37 | protected static CacheT cache =
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38 | new CacheT();
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39 |
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40 | private static bool cacheFilled = false;
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41 |
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42 | private static ReaderWriterLockSlim cacheLock =
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43 | new ReaderWriterLockSlim(LockRecursionPolicy.SupportsRecursion);
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44 |
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45 | protected ICollection<ICachedDataAdapter> parentAdapters =
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46 | new List<ICachedDataAdapter>();
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47 |
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48 | protected CachedDataAdapter(IDBSynchronizer synchronizer) {
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49 | cacheLock.EnterWriteLock();
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50 |
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51 | if (!cacheFilled) {
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52 | FillCache();
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53 | cacheFilled = true;
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54 | }
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55 |
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56 | cacheLock.ExitWriteLock();
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57 |
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58 | synchronizer.OnUpdate +=
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59 | new EventHandler(CachedDataAdapter_OnUpdate);
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60 | }
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61 |
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62 | protected virtual RowT FindSingleRow(Selector dbSelector,
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63 | Selector cacheSelector) {
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64 | cacheLock.EnterReadLock();
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65 |
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66 | RowT row =
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67 | FindSingleRow(cacheSelector);
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68 |
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69 | //not in cache
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70 | if (row == null) {
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71 | row =
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72 | FindSingleRow(dbSelector);
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73 | }
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74 |
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75 | cacheLock.ExitReadLock();
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76 |
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77 | return row;
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78 | }
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79 |
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80 | protected virtual IEnumerable<RowT> FindMultipleRows(Selector dbSelector,
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81 | Selector cacheSelector) {
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82 | cacheLock.EnterReadLock();
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83 |
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84 | IList<RowT> result =
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85 | new List<RowT>(cacheSelector());
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86 |
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87 | IEnumerable<RowT> result2 =
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88 | dbSelector();
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89 |
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90 | foreach (RowT row in result2) {
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91 | if (!IsCached(row)) {
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92 | result.Add(row);
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93 | }
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94 | }
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95 |
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96 | cacheLock.ExitReadLock();
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97 |
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98 | return result;
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99 | }
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100 |
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101 | protected virtual ObjT FindSingle(Selector dbSelector,
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102 | Selector cacheSelector) {
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103 | ObjT obj = default(ObjT);
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104 |
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105 | cacheLock.EnterReadLock();
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106 |
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107 | RowT row = FindSingleRow(dbSelector, cacheSelector);
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108 |
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109 | if (row != null) {
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110 | obj = new ObjT();
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111 | obj = Convert(row, obj);
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112 | }
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113 |
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114 | cacheLock.ExitReadLock();
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115 |
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116 | return obj;
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117 | }
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118 |
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119 | protected virtual ICollection<ObjT> FindMultiple(Selector dbSelector,
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120 | Selector cacheSelector) {
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121 | cacheLock.EnterReadLock();
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122 |
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123 | ICollection<ObjT> result =
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124 | FindMultiple(cacheSelector);
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125 |
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126 | ICollection<ObjT> resultDb =
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127 | FindMultiple(dbSelector);
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128 |
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129 | cacheLock.ExitReadLock();
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130 |
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131 | foreach (ObjT obj in resultDb) {
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132 | if (!result.Contains(obj))
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133 | result.Add(obj);
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134 | }
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135 |
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136 | return result;
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137 | }
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138 |
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139 | protected abstract RowT InsertNewRowInCache(ObjT obj);
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140 |
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141 | protected abstract void FillCache();
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142 |
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143 | protected abstract void SynchronizeWithDb();
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144 |
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145 | protected abstract bool PutInCache(ObjT obj);
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146 |
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147 | protected abstract RowT FindCachedById(Guid id);
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148 |
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149 | public void SyncWithDb() {
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150 | foreach (ICachedDataAdapter parent in this.parentAdapters) {
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151 | parent.SyncWithDb();
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152 | }
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153 |
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154 | cacheLock.EnterReadLock();
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155 |
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156 | this.SynchronizeWithDb();
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157 |
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158 | cacheLock.ExitReadLock();
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159 | }
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160 |
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161 | void CachedDataAdapter_OnUpdate(object sender, EventArgs e) {
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162 | this.SyncWithDb();
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163 | }
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164 |
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165 | protected virtual bool IsCached(RowT row) {
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166 | if (row == null)
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167 | return false;
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168 | else {
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169 | cacheLock.EnterReadLock();
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170 |
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171 | bool cached = FindCachedById((Guid)row[row.Table.PrimaryKey[0]]) != null;
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172 |
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173 | cacheLock.ExitReadLock();
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174 |
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175 | return cached;
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176 | }
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177 | }
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178 |
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179 | protected override RowT GetRowById(Guid id) {
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180 | cacheLock.EnterReadLock();
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181 |
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182 | RowT row =
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183 | FindCachedById(id);
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184 |
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185 | //not in cache
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186 | if (row == null)
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187 | row = FindSingleRow(
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188 | delegate() {
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189 | return FindById(id);
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190 | });
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191 |
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192 | cacheLock.ExitReadLock();
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193 |
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194 | return row;
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195 | }
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196 |
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197 | private void AddToCache(RowT row) {
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198 | cacheLock.EnterWriteLock();
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199 |
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200 | cache.ImportRow(row);
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201 | row.Table.Rows.Remove(row);
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202 |
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203 | cacheLock.ExitWriteLock();
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204 | }
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205 |
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206 | private RowT AddToCache(ObjT obj) {
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207 | cacheLock.EnterWriteLock();
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208 |
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209 | RowT row = InsertNewRowInCache(obj);
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210 |
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211 | cacheLock.ExitWriteLock();
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212 |
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213 | return row;
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214 | }
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215 |
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216 | private void RemoveRowFromCache(RowT row) {
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217 | cacheLock.EnterWriteLock();
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218 |
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219 | UpdateRow(row);
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220 |
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221 | row.Table.Rows.Remove(row);
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222 |
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223 | cacheLock.ExitWriteLock();
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224 | }
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225 |
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226 | public override ObjT GetById(Guid id) {
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227 | return FindSingle(
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228 | delegate() {
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229 | return FindById(id);
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230 | },
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231 | delegate() {
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232 | List<RowT> found =
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233 | new List<RowT>();
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234 | found.Add(
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235 | FindCachedById(id));
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236 | return found;
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237 | });
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238 | }
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239 |
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240 | public override void Update(ObjT obj) {
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241 | if (obj != null) {
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242 | RowT row = null;
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243 | Guid locked = Guid.Empty;
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244 |
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245 | if (obj.Id != Guid.Empty) {
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246 | LockRow(obj.Id);
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247 | locked = obj.Id;
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248 |
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249 | row = GetRowById(obj.Id);
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250 | } else {
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251 | obj.Id = Guid.NewGuid();
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252 | }
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253 |
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254 | if (row == null) {
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255 | if (PutInCache(obj)) {
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256 | row = AddToCache(obj);
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257 | } else {
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258 | row = InsertNewRow(obj);
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259 | UpdateRow(row);
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260 | }
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261 | }
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262 |
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263 | if (locked == Guid.Empty)
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264 | {
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265 | LockRow(obj.Id);
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266 | locked = obj.Id;
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267 | }
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268 |
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269 | ConvertObj(obj, row);
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270 |
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271 | if (!IsCached(row))
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272 | UpdateRow(row);
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273 |
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274 | if (IsCached(row) &&
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275 | !PutInCache(obj)) {
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276 | RemoveRowFromCache(row);
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277 | } else if (!IsCached(row) &&
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278 | PutInCache(obj)) {
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279 | AddToCache(row);
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280 | }
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281 |
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282 | UnlockRow(locked);
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283 | }
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284 | }
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285 | }
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286 | }
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287 |
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