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org.apache.torque.util.LargeSelect |
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1 | package org.apache.torque.util; |
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2 | ||
3 | /* |
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4 | * Licensed to the Apache Software Foundation (ASF) under one |
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5 | * or more contributor license agreements. See the NOTICE file |
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6 | * distributed with this work for additional information |
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7 | * regarding copyright ownership. The ASF licenses this file |
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8 | * to you under the Apache License, Version 2.0 (the |
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9 | * "License"); you may not use this file except in compliance |
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10 | * with the License. You may obtain a copy of the License at |
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11 | * |
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12 | * http://www.apache.org/licenses/LICENSE-2.0 |
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13 | * |
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14 | * Unless required by applicable law or agreed to in writing, |
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15 | * software distributed under the License is distributed on an |
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16 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
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17 | * KIND, either express or implied. See the License for the |
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18 | * specific language governing permissions and limitations |
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19 | * under the License. |
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20 | */ |
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21 | ||
22 | import java.io.IOException; |
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23 | import java.io.ObjectInputStream; |
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24 | import java.io.Serializable; |
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25 | import java.lang.reflect.Method; |
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26 | import java.sql.Connection; |
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27 | import java.sql.SQLException; |
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28 | import java.util.ArrayList; |
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29 | import java.util.Hashtable; |
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30 | import java.util.Iterator; |
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31 | import java.util.List; |
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32 | import java.util.Set; |
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33 | ||
34 | import org.apache.commons.logging.Log; |
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35 | import org.apache.commons.logging.LogFactory; |
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36 | import org.apache.torque.Torque; |
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37 | import org.apache.torque.TorqueException; |
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38 | ||
39 | import com.workingdogs.village.DataSetException; |
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40 | import com.workingdogs.village.QueryDataSet; |
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41 | ||
42 | /** |
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43 | * This class can be used to retrieve a large result set from a database query. |
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44 | * The query is started and then rows are returned a page at a time. The <code> |
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45 | * LargeSelect</code> is meant to be placed into the Session or User.Temp, so |
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46 | * that it can be used in response to several related requests. Note that in |
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47 | * order to use <code>LargeSelect</code> you need to be willing to accept the |
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48 | * fact that the result set may become inconsistent with the database if updates |
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49 | * are processed subsequent to the queries being executed. Specifying a memory |
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50 | * page limit of 1 will give you a consistent view of the records but the totals |
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51 | * may not be accurate and the performance will be terrible. In most cases |
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52 | * the potential for inconsistencies data should not cause any serious problems |
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53 | * and performance should be pretty good (but read on for further warnings). |
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54 | * |
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55 | * <p>The idea here is that the full query result would consume too much memory |
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56 | * and if displayed to a user the page would be too long to be useful. Rather |
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57 | * than loading the full result set into memory, a window of data (the memory |
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58 | * limit) is loaded and retrieved a page at a time. If a request occurs for |
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59 | * data that falls outside the currently loaded window of data then a new query |
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60 | * is executed to fetch the required data. Performance is optimized by |
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61 | * starting a thread to execute the database query and fetch the results. This |
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62 | * will perform best when paging forwards through the data, but a minor |
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63 | * optimization where the window is moved backwards by two rather than one page |
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64 | * is included for when a user pages past the beginning of the window. |
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65 | * |
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66 | * <p>As the query is performed in in steps, it is often the case that the total |
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67 | * number of records and pages of data is unknown. <code>LargeSelect</code> |
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68 | * provides various methods for indicating how many records and pages it is |
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69 | * currently aware of and for presenting this information to users. |
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70 | * |
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71 | * <p><code>LargeSelect</code> utilises the <code>Criteria</code> methods |
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72 | * <code>setOffset()</code> and <code>setLimit()</code> to limit the amount of |
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73 | * data retrieved from the database - these values are either passed through to |
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74 | * the DBMS when supported (efficient with the caveat below) or handled by |
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75 | * the Village API when it is not (not so efficient). At time of writing |
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76 | * <code>Criteria</code> will only pass the offset and limit through to MySQL |
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77 | * and PostgreSQL (with a few changes to <code>DBOracle</code> and <code> |
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78 | * BasePeer</code> Oracle support can be implemented by utilising the <code> |
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79 | * rownum</code> pseudo column). |
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80 | * |
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81 | * <p>As <code>LargeSelect</code> must re-execute the query each time the user |
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82 | * pages out of the window of loaded data, you should consider the impact of |
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83 | * non-index sort orderings and other criteria that will require the DBMS to |
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84 | * execute the entire query before filtering down to the offset and limit either |
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85 | * internally or via Village. |
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86 | * |
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87 | * <p>The memory limit defaults to 5 times the page size you specify, but |
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88 | * alternative constructors and the class method <code>setMemoryPageLimit() |
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89 | * </code> allow you to override this for a specific instance of |
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90 | * <code>LargeSelect</code> or future instances respectively. |
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91 | * |
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92 | * <p>Some of the constructors allow you to specify the name of the class to use |
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93 | * to build the returnd rows. This works by using reflection to find <code> |
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94 | * addSelectColumns(Criteria)</code> and <code>populateObjects(List)</code> |
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95 | * methods to add the necessary select columns to the criteria (only if it |
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96 | * doesn't already contain any) and to convert query results from Village |
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97 | * <code>Record</code> objects to a class defined within the builder class. |
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98 | * This allows you to use any of the Torque generated Peer classes, but also |
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99 | * makes it fairly simple to construct business object classes that can be used |
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100 | * for this purpose (simply copy and customise the <code>addSelectColumns() |
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101 | * </code>, <code>populateObjects()</code>, <code>row2Object()</code> and <code> |
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102 | * populateObject()</code> methods from an existing Peer class). |
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103 | * |
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104 | * <p>Typically you will create a <code>LargeSelect</code> using your <code> |
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105 | * Criteria</code> (perhaps created from the results of a search parameter |
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106 | * page), page size, memory page limit and return class name (for which you may |
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107 | * have defined a business object class before hand) and place this in user.Temp |
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108 | * thus: |
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109 | * |
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110 | * <pre> |
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111 | * data.getUser().setTemp("someName", largeSelect); |
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112 | * </pre> |
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113 | * |
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114 | * <p>In your template you will then use something along the lines of: |
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115 | * |
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116 | * <pre> |
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117 | * #set($largeSelect = $data.User.getTemp("someName")) |
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118 | * #set($searchop = $data.Parameters.getString("searchop")) |
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119 | * #if($searchop.equals("prev")) |
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120 | * #set($recs = $largeSelect.PreviousResults) |
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121 | * #else |
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122 | * #if($searchop.equals("goto")) |
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123 | * #set($recs = $largeSelect.getPage($data.Parameters.getInt("page", 1))) |
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124 | * #else |
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125 | * #set($recs = $largeSelect.NextResults) |
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126 | * #end |
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127 | * #end |
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128 | * </pre> |
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129 | * |
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130 | * <p>...to move through the records. <code>LargeSelect</code> implements a |
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131 | * number of convenience methods that make it easy to add all of the necessary |
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132 | * bells and whistles to your template. |
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133 | * |
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134 | * @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a> |
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135 | * @author <a href="mailto:seade@backstagetech.com.au">Scott Eade</a> |
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136 | * @version $Id: LargeSelect.java 534001 2007-05-01 10:46:05Z tv $ |
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137 | */ |
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138 | public class LargeSelect implements Runnable, Serializable |
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139 | { |
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140 | /** Serial version */ |
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141 | private static final long serialVersionUID = -1166842932571491942L; |
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142 | ||
143 | /** The number of records that a page consists of. */ |
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144 | private int pageSize; |
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145 | /** The maximum number of records to maintain in memory. */ |
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146 | private int memoryLimit; |
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147 | ||
148 | /** The record number of the first record in memory. */ |
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149 | 0 | private transient int blockBegin = 0; |
150 | /** The record number of the last record in memory. */ |
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151 | private transient int blockEnd; |
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152 | /** How much of the memory block is currently occupied with result data. */ |
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153 | 0 | private volatile int currentlyFilledTo = -1; |
154 | ||
155 | /** The SQL query that this <code>LargeSelect</code> represents. */ |
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156 | private String query; |
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157 | /** The database name to get from Torque. */ |
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158 | private String dbName; |
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159 | ||
160 | /** The memory store of records. */ |
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161 | 0 | private transient List results = null; |
162 | ||
163 | /** The thread that executes the query. */ |
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164 | 0 | private transient Thread thread = null; |
165 | /** |
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166 | * A flag used to kill the thread when the currently executing query is no |
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167 | * longer required. |
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168 | */ |
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169 | 0 | private transient volatile boolean killThread = false; |
170 | /** A flag that indicates whether or not the query thread is running. */ |
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171 | 0 | private transient volatile boolean threadRunning = false; |
172 | /** |
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173 | * An indication of whether or not the current query has completed |
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174 | * processing. |
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175 | */ |
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176 | 0 | private transient volatile boolean queryCompleted = false; |
177 | /** |
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178 | * An indication of whether or not the totals (records and pages) are at |
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179 | * their final values. |
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180 | */ |
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181 | 0 | private transient boolean totalsFinalized = false; |
182 | ||
183 | /** The cursor position in the result set. */ |
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184 | private int position; |
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185 | /** The total number of pages known to exist. */ |
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186 | 0 | private int totalPages = -1; |
187 | /** The total number of records known to exist. */ |
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188 | 0 | private int totalRecords = 0; |
189 | ||
190 | /** The criteria used for the query. */ |
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191 | 0 | private Criteria criteria = null; |
192 | /** The last page of results that were returned. */ |
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193 | private transient List lastResults; |
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194 | ||
195 | /** |
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196 | * The class that is possibly used to construct the criteria and used |
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197 | * to transform the Village Records into the desired OM or business objects. |
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198 | */ |
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199 | 0 | private Class returnBuilderClass = null; |
200 | /** |
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201 | * A reference to the method in the return builder class that will |
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202 | * convert the Village Records to the desired class. |
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203 | */ |
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204 | 0 | private transient Method populateObjectsMethod = null; |
205 | ||
206 | /** |
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207 | * The default value (">") used to indicate that the total number of |
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208 | * records or pages is unknown. |
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209 | */ |
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210 | public static final String DEFAULT_MORE_INDICATOR = ">"; |
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211 | ||
212 | /** |
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213 | * The value used to indicate that the total number of records or pages is |
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214 | * unknown (default: ">"). You can use <code>setMoreIndicator()</code> |
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215 | * to change this to whatever value you like (e.g. "more than"). |
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216 | */ |
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217 | 0 | private static String moreIndicator = DEFAULT_MORE_INDICATOR; |
218 | ||
219 | /** |
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220 | * The default value for the maximum number of pages of data to be retained |
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221 | * in memory. |
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222 | */ |
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223 | public static final int DEFAULT_MEMORY_LIMIT_PAGES = 5; |
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224 | ||
225 | /** |
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226 | * The maximum number of pages of data to be retained in memory. Use |
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227 | * <code>setMemoryPageLimit()</code> to provide your own value. |
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228 | */ |
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229 | 0 | private static int memoryPageLimit = DEFAULT_MEMORY_LIMIT_PAGES; |
230 | ||
231 | /** |
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232 | * The number of milliseconds to sleep when the result of a query |
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233 | * is not yet available. |
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234 | */ |
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235 | private static final int QUERY_NOT_COMPLETED_SLEEP_TIME = 500; |
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236 | ||
237 | /** |
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238 | * The number of milliseconds to sleep before retrying to stop a query. |
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239 | */ |
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240 | private static final int QUERY_STOP_SLEEP_TIME = 100; |
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241 | ||
242 | /** A place to store search parameters that relate to this query. */ |
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243 | 0 | private Hashtable params = null; |
244 | ||
245 | /** Logging */ |
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246 | 0 | private static Log log = LogFactory.getLog(LargeSelect.class); |
247 | ||
248 | /** |
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249 | * Creates a LargeSelect whose results are returned as a <code>List</code> |
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250 | * containing a maximum of <code>pageSize</code> Village <code>Record</code> |
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251 | * objects at a time, maintaining a maximum of |
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252 | * <code>LargeSelect.memoryPageLimit</code> pages of results in memory. |
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253 | * |
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254 | * @param criteria object used by BasePeer to build the query. In order to |
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255 | * allow this class to utilise database server implemented offsets and |
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256 | * limits (when available), the provided criteria must not have any limit or |
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257 | * offset defined. |
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258 | * @param pageSize number of rows to return in one block. |
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259 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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260 | * both of offset and limit, or if <code>pageSize</code> is less than 1; |
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261 | */ |
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262 | public LargeSelect(Criteria criteria, int pageSize) |
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263 | { |
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264 | 0 | this(criteria, pageSize, LargeSelect.memoryPageLimit); |
265 | 0 | } |
266 | ||
267 | /** |
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268 | * Creates a LargeSelect whose results are returned as a <code>List</code> |
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269 | * containing a maximum of <code>pageSize</code> Village <code>Record</code> |
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270 | * objects at a time, maintaining a maximum of <code>memoryPageLimit</code> |
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271 | * pages of results in memory. |
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272 | * |
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273 | * @param criteria object used by BasePeer to build the query. In order to |
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274 | * allow this class to utilise database server implemented offsets and |
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275 | * limits (when available), the provided criteria must not have any limit or |
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276 | * offset defined. |
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277 | * @param pageSize number of rows to return in one block. |
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278 | * @param memoryPageLimit maximum number of pages worth of rows to be held |
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279 | * in memory at one time. |
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280 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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281 | * both of offset and limit, or if <code>pageSize</code> or |
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282 | * <code>memoryLimitPages</code> are less than 1; |
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283 | */ |
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284 | public LargeSelect(Criteria criteria, int pageSize, class="keyword">int memoryPageLimit) |
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285 | 0 | { |
286 | 0 | init(criteria, pageSize, memoryPageLimit); |
287 | 0 | } |
288 | ||
289 | /** |
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290 | * Creates a LargeSelect whose results are returned as a <code>List</code> |
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291 | * containing a maximum of <code>pageSize</code> objects of the type |
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292 | * defined within the class named <code>returnBuilderClassName</code> at a |
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293 | * time, maintaining a maximum of <code>LargeSelect.memoryPageLimit</code> |
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294 | * pages of results in memory. |
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295 | * |
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296 | * @param criteria object used by BasePeer to build the query. In order to |
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297 | * allow this class to utilise database server implemented offsets and |
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298 | * limits (when available), the provided criteria must not have any limit or |
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299 | * offset defined. If the criteria does not include the definition of any |
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300 | * select columns the <code>addSelectColumns(Criteria)</code> method of |
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301 | * the class named as <code>returnBuilderClassName</code> will be used to |
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302 | * add them. |
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303 | * @param pageSize number of rows to return in one block. |
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304 | * @param returnBuilderClassName The name of the class that will be used to |
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305 | * build the result records (may implement <code>addSelectColumns(Criteria) |
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306 | * </code> and must implement <code>populateObjects(List)</code>). |
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307 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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308 | * both of offset and limit, if <code>pageSize</code> is less than 1, or if |
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309 | * problems are experienced locating and invoking either one or both of |
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310 | * <code>addSelectColumns(Criteria)</code> and <code> populateObjects(List) |
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311 | * </code> in the class named <code>returnBuilderClassName</code>. |
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312 | */ |
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313 | public LargeSelect( |
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314 | Criteria criteria, |
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315 | int pageSize, |
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316 | String returnBuilderClassName) |
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317 | { |
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318 | 0 | this( |
319 | criteria, |
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320 | pageSize, |
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321 | LargeSelect.memoryPageLimit, |
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322 | returnBuilderClassName); |
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323 | 0 | } |
324 | ||
325 | /** |
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326 | * Creates a LargeSelect whose results are returned as a <code>List</code> |
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327 | * containing a maximum of <code>pageSize</code> objects of the type |
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328 | * defined within the class named <code>returnBuilderClassName</code> at a |
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329 | * time, maintaining a maximum of <code>memoryPageLimit</code> pages of |
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330 | * results in memory. |
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331 | * |
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332 | * @param criteria object used by BasePeer to build the query. In order to |
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333 | * allow this class to utilise database server implemented offsets and |
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334 | * limits (when available), the provided criteria must not have any limit or |
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335 | * offset defined. If the criteria does not include the definition of any |
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336 | * select columns the <code>addSelectColumns(Criteria)</code> method of |
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337 | * the class named as <code>returnBuilderClassName</code> will be used to |
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338 | * add them. |
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339 | * @param pageSize number of rows to return in one block. |
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340 | * @param memoryPageLimit maximum number of pages worth of rows to be held |
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341 | * in memory at one time. |
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342 | * @param returnBuilderClassName The name of the class that will be used to |
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343 | * build the result records (may implement <code>addSelectColumns(Criteria) |
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344 | * </code> and must implement <code>populateObjects(List)</code>). |
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345 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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346 | * both of offset and limit, if <code>pageSize</code> or <code> |
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347 | * memoryLimitPages</code> are less than 1, or if problems are experienced |
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348 | * locating and invoking either one or both of <code> |
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349 | * addSelectColumns(Criteria)</code> and <code> populateObjects(List)</code> |
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350 | * in the class named <code>returnBuilderClassName</code>. |
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351 | */ |
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352 | public LargeSelect( |
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353 | Criteria criteria, |
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354 | int pageSize, |
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355 | int memoryPageLimit, |
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356 | String returnBuilderClassName) |
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357 | 0 | { |
358 | try |
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359 | { |
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360 | 0 | this.returnBuilderClass = Class.forName(returnBuilderClassName); |
361 | ||
362 | // Add the select columns if necessary. |
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363 | 0 | if (criteria.getSelectColumns().size() == 0) |
364 | { |
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365 | 0 | Class[] argTypes = { Criteria.class }; |
366 | 0 | Method selectColumnAdder = |
367 | returnBuilderClass.getMethod("addSelectColumns", argTypes); |
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368 | 0 | Object[] theArgs = { criteria }; |
369 | 0 | selectColumnAdder.invoke(returnBuilderClass.newInstance(), |
370 | theArgs); |
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371 | } |
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372 | } |
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373 | 0 | catch (Exception e) |
374 | { |
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375 | 0 | throw new IllegalArgumentException( |
376 | "The class named as returnBuilderClassName does not " |
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377 | + "provide the necessary facilities - see javadoc."); |
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378 | 0 | } |
379 | ||
380 | 0 | init(criteria, pageSize, memoryPageLimit); |
381 | 0 | } |
382 | ||
383 | /** |
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384 | * Access the populateObjects method. |
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385 | * |
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386 | * @throws SecurityException if the security manager does not allow |
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387 | * access to the method. |
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388 | * @throws NoSuchMethodException if the poulateObjects method does not |
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389 | * exist. |
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390 | */ |
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391 | private Method getPopulateObjectsMethod() |
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392 | throws NoSuchMethodException |
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393 | { |
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394 | 0 | if (null == populateObjectsMethod) |
395 | { |
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396 | 0 | Class[] argTypes = { List.class }; |
397 | 0 | populateObjectsMethod |
398 | = returnBuilderClass.getMethod("populateObjects", argTypes); |
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399 | } |
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400 | 0 | return populateObjectsMethod; |
401 | } |
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402 | ||
403 | /** |
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404 | * Called by the constructors to start the query. |
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405 | * |
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406 | * @param criteria Object used by <code>BasePeer</code> to build the query. |
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407 | * In order to allow this class to utilise database server implemented |
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408 | * offsets and limits (when available), the provided criteria must not have |
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409 | * any limit or offset defined. |
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410 | * @param pageSize number of rows to return in one block. |
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411 | * @param memoryLimitPages maximum number of pages worth of rows to be held |
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412 | * in memory at one time. |
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413 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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414 | * both of offset and limit and if <code>pageSize</code> or |
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415 | * <code>memoryLimitPages</code> are less than 1; |
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416 | */ |
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417 | private void init(Criteria criteria, int pageSize, class="keyword">int memoryLimitPages) |
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418 | { |
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419 | 0 | if (criteria.getOffset() != 0 || criteria.getLimit() != -1) |
420 | { |
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421 | 0 | throw new IllegalArgumentException( |
422 | "criteria must not use Offset and/or Limit."); |
|
423 | } |
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424 | ||
425 | 0 | if (pageSize < 1) |
426 | { |
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427 | 0 | throw new IllegalArgumentException( |
428 | "pageSize must be greater than zero."); |
|
429 | } |
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430 | ||
431 | 0 | if (memoryLimitPages < 1) |
432 | { |
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433 | 0 | throw new IllegalArgumentException( |
434 | "memoryPageLimit must be greater than zero."); |
|
435 | } |
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436 | ||
437 | 0 | this.pageSize = pageSize; |
438 | 0 | this.memoryLimit = pageSize * memoryLimitPages; |
439 | 0 | this.criteria = criteria; |
440 | 0 | dbName = criteria.getDbName(); |
441 | 0 | blockEnd = blockBegin + memoryLimit - 1; |
442 | 0 | startQuery(pageSize); |
443 | 0 | } |
444 | ||
445 | /** |
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446 | * Retrieve a specific page, if it exists. |
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447 | * |
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448 | * @param pageNumber the number of the page to be retrieved - must be |
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449 | * greater than zero. An empty <code>List</code> will be returned if |
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450 | * <code>pageNumber</code> exceeds the total number of pages that exist. |
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451 | * @return a <code>List</code> of query results containing a maximum of |
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452 | * <code>pageSize</code> results. |
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453 | * @throws IllegalArgumentException when <code>pageNo</code> is not |
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454 | * greater than zero. |
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455 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
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456 | * method runs into problems or a sleep is unexpectedly interrupted. |
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457 | */ |
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458 | public List getPage(int pageNumber) throws TorqueException |
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459 | { |
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460 | 0 | if (pageNumber < 1) |
461 | { |
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462 | 0 | throw new IllegalArgumentException( |
463 | "pageNumber must be greater than zero."); |
|
464 | } |
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465 | 0 | return getResults((pageNumber - 1) * pageSize); |
466 | } |
|
467 | ||
468 | /** |
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469 | * Gets the next page of rows. |
|
470 | * |
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471 | * @return a <code>List</code> of query results containing a maximum of |
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472 | * <code>pageSize</code> reslts. |
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473 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
474 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
475 | */ |
|
476 | public List getNextResults() throws TorqueException |
|
477 | { |
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478 | 0 | if (!getNextResultsAvailable()) |
479 | { |
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480 | 0 | return getCurrentPageResults(); |
481 | } |
|
482 | 0 | return getResults(position); |
483 | } |
|
484 | ||
485 | /** |
|
486 | * Provide access to the results from the current page. |
|
487 | * |
|
488 | * @return a <code>List</code> of query results containing a maximum of |
|
489 | * <code>pageSize</code> reslts. |
|
490 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
491 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
492 | */ |
|
493 | public List getCurrentPageResults() throws TorqueException |
|
494 | { |
|
495 | 0 | return null == lastResults && position > 0 |
496 | ? getResults(position) : lastResults; |
|
497 | } |
|
498 | ||
499 | /** |
|
500 | * Gets the previous page of rows. |
|
501 | * |
|
502 | * @return a <code>List</code> of query results containing a maximum of |
|
503 | * <code>pageSize</code> reslts. |
|
504 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
505 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
506 | */ |
|
507 | public List getPreviousResults() throws TorqueException |
|
508 | { |
|
509 | 0 | if (!getPreviousResultsAvailable()) |
510 | { |
|
511 | 0 | return getCurrentPageResults(); |
512 | } |
|
513 | ||
514 | int start; |
|
515 | 0 | if (position - 2 * pageSize < 0) |
516 | { |
|
517 | 0 | start = 0; |
518 | } |
|
519 | else |
|
520 | { |
|
521 | 0 | start = position - 2 * pageSize; |
522 | } |
|
523 | 0 | return getResults(start); |
524 | } |
|
525 | ||
526 | /** |
|
527 | * Gets a page of rows starting at a specified row. |
|
528 | * |
|
529 | * @param start the starting row. |
|
530 | * @return a <code>List</code> of query results containing a maximum of |
|
531 | * <code>pageSize</code> reslts. |
|
532 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
533 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
534 | */ |
|
535 | private List getResults(int start) throws TorqueException |
|
536 | { |
|
537 | 0 | return getResults(start, pageSize); |
538 | } |
|
539 | ||
540 | /** |
|
541 | * Gets a block of rows starting at a specified row and containing a |
|
542 | * specified number of rows. |
|
543 | * |
|
544 | * @param start the starting row. |
|
545 | * @param size the number of rows. |
|
546 | * @return a <code>List</code> of query results containing a maximum of |
|
547 | * <code>pageSize</code> reslts. |
|
548 | * @throws IllegalArgumentException if <code>size > memoryLimit</code> or |
|
549 | * <code>start</code> and <code>size</code> result in a situation that is |
|
550 | * not catered for. |
|
551 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
552 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
553 | */ |
|
554 | private synchronized List getResults(int start, class="keyword">int size) |
|
555 | throws TorqueException |
|
556 | { |
|
557 | 0 | if (log.isDebugEnabled()) |
558 | { |
|
559 | 0 | log.debug("getResults(start: " + start |
560 | + ", size: " + size + ") invoked."); |
|
561 | } |
|
562 | ||
563 | 0 | if (size > memoryLimit) |
564 | { |
|
565 | 0 | throw new IllegalArgumentException("size (" + size |
566 | + ") exceeds memory limit (" + memoryLimit + ")."); |
|
567 | } |
|
568 | ||
569 | // Request was for a block of rows which should be in progess. |
|
570 | // If the rows have not yet been returned, wait for them to be |
|
571 | // retrieved. |
|
572 | 0 | if (start >= blockBegin && (start + size - 1) <= blockEnd) |
573 | { |
|
574 | 0 | if (log.isDebugEnabled()) |
575 | { |
|
576 | 0 | log.debug("getResults(): Sleeping until " |
577 | + "start+size-1 (" + (start + size - 1) |
|
578 | + ") > currentlyFilledTo (" + currentlyFilledTo |
|
579 | + ") && !queryCompleted (!" + queryCompleted + ")"); |
|
580 | } |
|
581 | 0 | while (((start + size - 1) > currentlyFilledTo) && !queryCompleted) |
582 | { |
|
583 | try |
|
584 | { |
|
585 | 0 | Thread.sleep(QUERY_NOT_COMPLETED_SLEEP_TIME); |
586 | } |
|
587 | 0 | catch (InterruptedException e) |
588 | { |
|
589 | 0 | throw new TorqueException("Unexpected interruption", e); |
590 | 0 | } |
591 | } |
|
592 | } |
|
593 | ||
594 | // Going in reverse direction, trying to limit db hits so assume user |
|
595 | // might want at least 2 sets of data. |
|
596 | 0 | else if (start < blockBegin && start >= 0) |
597 | { |
|
598 | 0 | if (log.isDebugEnabled()) |
599 | { |
|
600 | 0 | log.debug("getResults(): Paging backwards as start (" + start |
601 | + ") < blockBegin (" + blockBegin + ") && start >= 0"); |
|
602 | } |
|
603 | 0 | stopQuery(); |
604 | 0 | if (memoryLimit >= 2 * size) |
605 | { |
|
606 | 0 | blockBegin = start - size; |
607 | 0 | if (blockBegin < 0) |
608 | { |
|
609 | 0 | blockBegin = 0; |
610 | } |
|
611 | } |
|
612 | else |
|
613 | { |
|
614 | 0 | blockBegin = start; |
615 | } |
|
616 | 0 | blockEnd = blockBegin + memoryLimit - 1; |
617 | 0 | startQuery(size); |
618 | // Re-invoke getResults() to provide the wait processing. |
|
619 | 0 | return getResults(start, size); |
620 | } |
|
621 | ||
622 | // Assume we are moving on, do not retrieve any records prior to start. |
|
623 | 0 | else if ((start + size - 1) > blockEnd) |
624 | { |
|
625 | 0 | if (log.isDebugEnabled()) |
626 | { |
|
627 | 0 | log.debug("getResults(): Paging past end of loaded data as " |
628 | + "start+size-1 (" + (start + size - 1) |
|
629 | + ") > blockEnd (" + blockEnd + ")"); |
|
630 | } |
|
631 | 0 | stopQuery(); |
632 | 0 | blockBegin = start; |
633 | 0 | blockEnd = blockBegin + memoryLimit - 1; |
634 | 0 | startQuery(size); |
635 | // Re-invoke getResults() to provide the wait processing. |
|
636 | 0 | return getResults(start, size); |
637 | } |
|
638 | ||
639 | else |
|
640 | { |
|
641 | 0 | throw new IllegalArgumentException("Parameter configuration not " |
642 | + "accounted for."); |
|
643 | } |
|
644 | ||
645 | 0 | int fromIndex = start - blockBegin; |
646 | 0 | int toIndex = fromIndex + Math.min(size, results.size() - fromIndex); |
647 | ||
648 | 0 | if (log.isDebugEnabled()) |
649 | { |
|
650 | 0 | log.debug("getResults(): Retrieving records from results elements " |
651 | + "start-blockBegin (" + fromIndex + ") through " |
|
652 | + "fromIndex + Math.min(size, results.size() - fromIndex) (" |
|
653 | + toIndex + ")"); |
|
654 | } |
|
655 | ||
656 | List returnResults; |
|
657 | ||
658 | 0 | synchronized (results) |
659 | { |
|
660 | 0 | returnResults = new ArrayList(results.subList(fromIndex, toIndex)); |
661 | 0 | } |
662 | ||
663 | 0 | if (null != returnBuilderClass) |
664 | { |
|
665 | // Invoke the populateObjects() method |
|
666 | 0 | Object[] theArgs = { returnResults }; |
667 | try |
|
668 | { |
|
669 | 0 | returnResults = (List) getPopulateObjectsMethod().invoke( |
670 | returnBuilderClass.newInstance(), theArgs); |
|
671 | } |
|
672 | 0 | catch (Exception e) |
673 | { |
|
674 | 0 | throw new TorqueException("Unable to populate results", e); |
675 | 0 | } |
676 | } |
|
677 | 0 | position = start + size; |
678 | 0 | lastResults = returnResults; |
679 | 0 | return class="keyword">returnResults; |
680 | } |
|
681 | ||
682 | /** |
|
683 | * A background thread that retrieves the rows. |
|
684 | */ |
|
685 | public void run() |
|
686 | { |
|
687 | boolean dbSupportsNativeLimit; |
|
688 | boolean dbSupportsNativeOffset; |
|
689 | try |
|
690 | { |
|
691 | 0 | dbSupportsNativeLimit |
692 | = (Torque.getDB(dbName).supportsNativeLimit()); |
|
693 | 0 | dbSupportsNativeOffset |
694 | = (Torque.getDB(dbName).supportsNativeOffset()); |
|
695 | } |
|
696 | 0 | catch (TorqueException e) |
697 | { |
|
698 | 0 | log.error("run() : Exiting :", e); |
699 | // we cannot execute further because Torque is not initialized |
|
700 | // correctly |
|
701 | 0 | return; |
702 | 0 | } |
703 | ||
704 | int size; |
|
705 | 0 | if (dbSupportsNativeLimit && dbSupportsNativeOffset) |
706 | { |
|
707 | // retrieve one page at a time |
|
708 | 0 | size = pageSize; |
709 | } |
|
710 | else |
|
711 | { |
|
712 | // retrieve the whole block at once and add the offset, |
|
713 | // and add one record to check if we have reached the end of the |
|
714 | // data |
|
715 | 0 | size = blockBegin + memoryLimit + 1; |
716 | } |
|
717 | /* The connection to the database. */ |
|
718 | 0 | Connection conn = null; |
719 | /** Used to retrieve query results from Village. */ |
|
720 | 0 | QueryDataSet qds = null; |
721 | ||
722 | try |
|
723 | { |
|
724 | // Add 1 to memory limit to check if the query ends on a page break. |
|
725 | 0 | results = new ArrayList(memoryLimit + 1); |
726 | ||
727 | // Use the criteria to limit the rows that are retrieved to the |
|
728 | // block of records that fit in the predefined memoryLimit. |
|
729 | 0 | if (dbSupportsNativeLimit) |
730 | { |
|
731 | 0 | if (dbSupportsNativeOffset) |
732 | { |
|
733 | 0 | criteria.setOffset(blockBegin); |
734 | // Add 1 to memory limit to check if the query ends on a |
|
735 | // page break. |
|
736 | 0 | criteria.setLimit(memoryLimit + 1); |
737 | } |
|
738 | else |
|
739 | { |
|
740 | 0 | criteria.setLimit(blockBegin + memoryLimit + 1); |
741 | } |
|
742 | } |
|
743 | ||
744 | /* |
|
745 | * Fix criterions relating to booleanint or booleanchar columns |
|
746 | * The defaultTableMap parameter in this call is null because we have |
|
747 | * no default peer class inside LargeSelect. This means that all |
|
748 | * columns not fully qualified will not be modified. |
|
749 | */ |
|
750 | 0 | BasePeer.correctBooleans(criteria, null); |
751 | ||
752 | 0 | query = BasePeer.createQueryString(criteria); |
753 | ||
754 | // Get a connection to the db. |
|
755 | 0 | conn = Torque.getConnection(dbName); |
756 | ||
757 | // Execute the query. |
|
758 | 0 | if (log.isDebugEnabled()) |
759 | { |
|
760 | 0 | log.debug("run(): query = " + query); |
761 | 0 | log.debug("run(): memoryLimit = " + memoryLimit); |
762 | 0 | log.debug("run(): blockBegin = " + blockBegin); |
763 | 0 | log.debug("run(): blockEnd = " + blockEnd); |
764 | } |
|
765 | 0 | qds = new QueryDataSet(conn, query); |
766 | ||
767 | // Continue getting rows one page at a time until the memory limit |
|
768 | // is reached, all results have been retrieved, or the rest |
|
769 | // of the results have been determined to be irrelevant. |
|
770 | while (!killThread |
|
771 | && !qds.allRecordsRetrieved() |
|
772 | 0 | && currentlyFilledTo + pageSize <= blockEnd) |
773 | { |
|
774 | // This caters for when memoryLimit is not a multiple of |
|
775 | // pageSize which it never is because we always add 1 above. |
|
776 | // not applicable if the db has no native limit where this |
|
777 | // was already considered |
|
778 | 0 | if ((currentlyFilledTo + pageSize) >= blockEnd |
779 | && dbSupportsNativeLimit) |
|
780 | { |
|
781 | // Add 1 to check if the query ends on a page break. |
|
782 | 0 | size = blockEnd - currentlyFilledTo + 1; |
783 | } |
|
784 | ||
785 | 0 | if (log.isDebugEnabled()) |
786 | { |
|
787 | 0 | log.debug("run(): Invoking BasePeer.getSelectResults(qds, " |
788 | + size + ", false)"); |
|
789 | } |
|
790 | ||
791 | 0 | List tempResults |
792 | = BasePeer.getSelectResults(qds, size, false); |
|
793 | ||
794 | 0 | int startIndex = dbSupportsNativeOffset ? 0 : blockBegin; |
795 | ||
796 | 0 | synchronized (results) |
797 | { |
|
798 | 0 | for (int i = startIndex, n = tempResults.size(); i < n; i++) |
799 | { |
|
800 | 0 | results.add(tempResults.get(i)); |
801 | } |
|
802 | 0 | } |
803 | ||
804 | 0 | if (dbSupportsNativeLimit && dbSupportsNativeOffset) |
805 | { |
|
806 | 0 | currentlyFilledTo += tempResults.size(); |
807 | } |
|
808 | else |
|
809 | { |
|
810 | 0 | currentlyFilledTo = tempResults.size() - 1 - blockBegin; |
811 | } |
|
812 | ||
813 | 0 | boolean perhapsLastPage = true; |
814 | ||
815 | // If the extra record was indeed found then we know we are not |
|
816 | // on the last page but we must now get rid of it. |
|
817 | 0 | if ((dbSupportsNativeLimit |
818 | && (results.size() == memoryLimit + 1)) |
|
819 | || (!dbSupportsNativeLimit |
|
820 | && currentlyFilledTo >= memoryLimit)) |
|
821 | { |
|
822 | 0 | synchronized (results) |
823 | { |
|
824 | 0 | results.remove(currentlyFilledTo--); |
825 | 0 | } |
826 | 0 | perhapsLastPage = false; |
827 | } |
|
828 | ||
829 | 0 | if (results.size() > 0 |
830 | && blockBegin + currentlyFilledTo >= totalRecords) |
|
831 | { |
|
832 | // Add 1 because index starts at 0 |
|
833 | 0 | totalRecords = blockBegin + currentlyFilledTo + 1; |
834 | } |
|
835 | ||
836 | // if the db has limited the datasets, we must retrieve all |
|
837 | // datasets. If not, we are always finished because we fetch |
|
838 | // the whole block at once. |
|
839 | 0 | if (qds.allRecordsRetrieved() |
840 | || !dbSupportsNativeLimit) |
|
841 | { |
|
842 | 0 | queryCompleted = true; |
843 | // The following ugly condition ensures that the totals are |
|
844 | // not finalized when a user does something like requesting |
|
845 | // a page greater than what exists in the database. |
|
846 | 0 | if (perhapsLastPage |
847 | && getCurrentPageNumber() <= getTotalPages()) |
|
848 | { |
|
849 | 0 | totalsFinalized = true; |
850 | } |
|
851 | } |
|
852 | 0 | qds.clearRecords(); |
853 | } |
|
854 | ||
855 | 0 | if (log.isDebugEnabled()) |
856 | { |
|
857 | 0 | log.debug("run(): While loop terminated because either:"); |
858 | 0 | log.debug("run(): 1. qds.allRecordsRetrieved(): " |
859 | + qds.allRecordsRetrieved()); |
|
860 | 0 | log.debug("run(): 2. killThread: " + killThread); |
861 | 0 | log.debug("run(): 3. !(currentlyFilledTo + size <= blockEnd): !" |
862 | + (currentlyFilledTo + pageSize <= blockEnd)); |
|
863 | 0 | log.debug("run(): - currentlyFilledTo: " + currentlyFilledTo); |
864 | 0 | log.debug("run(): - size: " + pageSize); |
865 | 0 | log.debug("run(): - blockEnd: " + blockEnd); |
866 | 0 | log.debug("run(): - results.size(): " + results.size()); |
867 | } |
|
868 | 0 | } |
869 | 0 | catch (TorqueException e) |
870 | { |
|
871 | 0 | log.error(e); |
872 | 0 | } |
873 | 0 | catch (SQLException e) |
874 | { |
|
875 | 0 | log.error(e); |
876 | 0 | } |
877 | 0 | catch (DataSetException e) |
878 | { |
|
879 | 0 | log.error(e); |
880 | 0 | } |
881 | finally |
|
882 | { |
|
883 | 0 | try |
884 | { |
|
885 | 0 | if (qds != null) |
886 | { |
|
887 | 0 | qds.close(); |
888 | } |
|
889 | 0 | Torque.closeConnection(conn); |
890 | } |
|
891 | 0 | catch (SQLException e) |
892 | { |
|
893 | 0 | log.error(e); |
894 | } |
|
895 | 0 | catch (DataSetException e) |
896 | { |
|
897 | 0 | log.error(e); |
898 | 0 | } |
899 | 0 | threadRunning = false; |
900 | 0 | } |
901 | 0 | } |
902 | ||
903 | /** |
|
904 | * Starts a new thread to retrieve the result set. |
|
905 | * |
|
906 | * @param initialSize the initial size for each block. |
|
907 | */ |
|
908 | private synchronized void startQuery(int initialSize) |
|
909 | { |
|
910 | 0 | if (!threadRunning) |
911 | { |
|
912 | 0 | pageSize = initialSize; |
913 | 0 | currentlyFilledTo = -1; |
914 | 0 | queryCompleted = false; |
915 | 0 | thread = new Thread(this); |
916 | 0 | thread.start(); |
917 | 0 | threadRunning = true; |
918 | } |
|
919 | 0 | } |
920 | ||
921 | /** |
|
922 | * Used to stop filling the memory with the current block of results, if it |
|
923 | * has been determined that they are no longer relevant. |
|
924 | * |
|
925 | * @throws TorqueException if a sleep is interrupted. |
|
926 | */ |
|
927 | private synchronized void stopQuery() throws TorqueException |
|
928 | { |
|
929 | 0 | if (threadRunning) |
930 | { |
|
931 | 0 | killThread = true; |
932 | 0 | while (thread.isAlive()) |
933 | { |
|
934 | try |
|
935 | { |
|
936 | 0 | Thread.sleep(QUERY_STOP_SLEEP_TIME); |
937 | } |
|
938 | 0 | catch (InterruptedException e) |
939 | { |
|
940 | 0 | throw new TorqueException("Unexpected interruption", e); |
941 | 0 | } |
942 | } |
|
943 | 0 | killThread = false; |
944 | } |
|
945 | 0 | } |
946 | ||
947 | /** |
|
948 | * Retrieve the number of the current page. |
|
949 | * |
|
950 | * @return the current page number. |
|
951 | */ |
|
952 | public int getCurrentPageNumber() |
|
953 | { |
|
954 | 0 | return position / pageSize; |
955 | } |
|
956 | ||
957 | /** |
|
958 | * Retrieve the total number of search result records that are known to |
|
959 | * exist (this will be the actual value when the query has completeted (see |
|
960 | * <code>getTotalsFinalized()</code>). The convenience method |
|
961 | * <code>getRecordProgressText()</code> may be more useful for presenting to |
|
962 | * users. |
|
963 | * |
|
964 | * @return the number of result records known to exist (not accurate until |
|
965 | * <code>getTotalsFinalized()</code> returns <code>true</code>). |
|
966 | */ |
|
967 | public int getTotalRecords() |
|
968 | { |
|
969 | 0 | return totalRecords; |
970 | } |
|
971 | ||
972 | /** |
|
973 | * Provide an indication of whether or not paging of results will be |
|
974 | * required. |
|
975 | * |
|
976 | * @return <code>true</code> when multiple pages of results exist. |
|
977 | */ |
|
978 | public boolean getPaginated() |
|
979 | { |
|
980 | // Handle a page memory limit of 1 page. |
|
981 | 0 | if (!getTotalsFinalized()) |
982 | { |
|
983 | 0 | return true; |
984 | } |
|
985 | 0 | return blockBegin + currentlyFilledTo + 1 > pageSize; |
986 | } |
|
987 | ||
988 | /** |
|
989 | * Retrieve the total number of pages of search results that are known to |
|
990 | * exist (this will be the actual value when the query has completeted (see |
|
991 | * <code>getQyeryCompleted()</code>). The convenience method |
|
992 | * <code>getPageProgressText()</code> may be more useful for presenting to |
|
993 | * users. |
|
994 | * |
|
995 | * @return the number of pages of results known to exist (not accurate until |
|
996 | * <code>getTotalsFinalized()</code> returns <code>true</code>). |
|
997 | */ |
|
998 | public int getTotalPages() |
|
999 | { |
|
1000 | 0 | if (totalPages > -1) |
1001 | { |
|
1002 | 0 | return totalPages; |
1003 | } |
|
1004 | ||
1005 | 0 | int tempPageCount = getTotalRecords() / pageSize |
1006 | + (getTotalRecords() % pageSize > 0 ? 1 : 0); |
|
1007 | ||
1008 | 0 | if (getTotalsFinalized()) |
1009 | { |
|
1010 | 0 | totalPages = tempPageCount; |
1011 | } |
|
1012 | ||
1013 | 0 | return tempPageCount; |
1014 | } |
|
1015 | ||
1016 | /** |
|
1017 | * Retrieve the page size. |
|
1018 | * |
|
1019 | * @return the number of records returned on each invocation of |
|
1020 | * <code>getNextResults()</code>/<code>getPreviousResults()</code>. |
|
1021 | */ |
|
1022 | public int getPageSize() |
|
1023 | { |
|
1024 | 0 | return pageSize; |
1025 | } |
|
1026 | ||
1027 | /** |
|
1028 | * Provide access to indicator that the total values for the number of |
|
1029 | * records and pages are now accurate as opposed to known upper limits. |
|
1030 | * |
|
1031 | * @return <code>true</code> when the totals are known to have been fully |
|
1032 | * computed. |
|
1033 | */ |
|
1034 | public boolean getTotalsFinalized() |
|
1035 | { |
|
1036 | 0 | return totalsFinalized; |
1037 | } |
|
1038 | ||
1039 | /** |
|
1040 | * Provide a way of changing the more pages/records indicator. |
|
1041 | * |
|
1042 | * @param moreIndicator the indicator to use in place of the default |
|
1043 | * (">"). |
|
1044 | */ |
|
1045 | public static void setMoreIndicator(String moreIndicator) |
|
1046 | { |
|
1047 | 0 | LargeSelect.moreIndicator = moreIndicator; |
1048 | 0 | } |
1049 | ||
1050 | /** |
|
1051 | * Retrieve the more pages/records indicator. |
|
1052 | */ |
|
1053 | public static String getMoreIndicator() |
|
1054 | { |
|
1055 | 0 | return LargeSelect.moreIndicator; |
1056 | } |
|
1057 | ||
1058 | /** |
|
1059 | * Sets the multiplier that will be used to compute the memory limit when a |
|
1060 | * constructor with no memory page limit is used - the memory limit will be |
|
1061 | * this number multiplied by the page size. |
|
1062 | * |
|
1063 | * @param memoryPageLimit the maximum number of pages to be in memory |
|
1064 | * at one time. |
|
1065 | */ |
|
1066 | public static void setMemoryPageLimit(int memoryPageLimit) |
|
1067 | { |
|
1068 | 0 | LargeSelect.memoryPageLimit = memoryPageLimit; |
1069 | 0 | } |
1070 | ||
1071 | /** |
|
1072 | * Retrieves the multiplier that will be used to compute the memory limit |
|
1073 | * when a constructor with no memory page limit is used - the memory limit |
|
1074 | * will be this number multiplied by the page size. |
|
1075 | */ |
|
1076 | public static int getMemoryPageLimit() |
|
1077 | { |
|
1078 | 0 | return LargeSelect.memoryPageLimit; |
1079 | } |
|
1080 | ||
1081 | /** |
|
1082 | * A convenience method that provides text showing progress through the |
|
1083 | * selected rows on a page basis. |
|
1084 | * |
|
1085 | * @return progress text in the form of "1 of > 5" where ">" can be |
|
1086 | * configured using <code>setMoreIndicator()</code>. |
|
1087 | */ |
|
1088 | public String getPageProgressText() |
|
1089 | { |
|
1090 | 0 | StringBuffer result = new StringBuffer(); |
1091 | 0 | result.append(getCurrentPageNumber()); |
1092 | 0 | result.append(" of "); |
1093 | 0 | if (!totalsFinalized) |
1094 | { |
|
1095 | 0 | result.append(moreIndicator); |
1096 | 0 | result.append(" "); |
1097 | } |
|
1098 | 0 | result.append(getTotalPages()); |
1099 | 0 | return result.toString(); |
1100 | } |
|
1101 | ||
1102 | /** |
|
1103 | * Provides a count of the number of rows to be displayed on the current |
|
1104 | * page - for the last page this may be less than the configured page size. |
|
1105 | * |
|
1106 | * @return the number of records that are included on the current page of |
|
1107 | * results. |
|
1108 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
1109 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
1110 | */ |
|
1111 | public int getCurrentPageSize() throws TorqueException |
|
1112 | { |
|
1113 | 0 | if (null == getCurrentPageResults()) |
1114 | { |
|
1115 | 0 | return 0; |
1116 | } |
|
1117 | 0 | return getCurrentPageResults().size(); |
1118 | } |
|
1119 | ||
1120 | /** |
|
1121 | * Provide the record number of the first row included on the current page. |
|
1122 | * |
|
1123 | * @return The record number of the first row of the current page. |
|
1124 | */ |
|
1125 | public int getFirstRecordNoForPage() |
|
1126 | { |
|
1127 | 0 | if (getCurrentPageNumber() < 1) |
1128 | { |
|
1129 | 0 | return 0; |
1130 | } |
|
1131 | 0 | return (getCurrentPageNumber() - 1) * getPageSize() + 1; |
1132 | } |
|
1133 | ||
1134 | /** |
|
1135 | * Provide the record number of the last row included on the current page. |
|
1136 | * |
|
1137 | * @return the record number of the last row of the current page. |
|
1138 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
1139 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
1140 | */ |
|
1141 | public int getLastRecordNoForPage() throws TorqueException |
|
1142 | { |
|
1143 | 0 | if (0 == getCurrentPageNumber()) |
1144 | { |
|
1145 | 0 | return 0; |
1146 | } |
|
1147 | 0 | return (getCurrentPageNumber() - 1) * getPageSize() |
1148 | + getCurrentPageSize(); |
|
1149 | } |
|
1150 | ||
1151 | /** |
|
1152 | * A convenience method that provides text showing progress through the |
|
1153 | * selected rows on a record basis. |
|
1154 | * |
|
1155 | * @return progress text in the form of "26 - 50 of > 250" where ">" |
|
1156 | * can be configured using <code>setMoreIndicator()</code>. |
|
1157 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
1158 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
1159 | */ |
|
1160 | public String getRecordProgressText() throws TorqueException |
|
1161 | { |
|
1162 | 0 | StringBuffer result = new StringBuffer(); |
1163 | 0 | result.append(getFirstRecordNoForPage()); |
1164 | 0 | result.append(" - "); |
1165 | 0 | result.append(getLastRecordNoForPage()); |
1166 | 0 | result.append(" of "); |
1167 | 0 | if (!totalsFinalized) |
1168 | { |
|
1169 | 0 | result.append(moreIndicator); |
1170 | 0 | result.append(" "); |
1171 | } |
|
1172 | 0 | result.append(getTotalRecords()); |
1173 | 0 | return result.toString(); |
1174 | } |
|
1175 | ||
1176 | /** |
|
1177 | * Indicates if further result pages are available. |
|
1178 | * |
|
1179 | * @return <code>true</code> when further results are available. |
|
1180 | */ |
|
1181 | public boolean getNextResultsAvailable() |
|
1182 | { |
|
1183 | 0 | if (!totalsFinalized || getCurrentPageNumber() < getTotalPages()) |
1184 | { |
|
1185 | 0 | return true; |
1186 | } |
|
1187 | 0 | return false; |
1188 | } |
|
1189 | ||
1190 | /** |
|
1191 | * Indicates if previous results pages are available. |
|
1192 | * |
|
1193 | * @return <code>true</code> when previous results are available. |
|
1194 | */ |
|
1195 | public boolean getPreviousResultsAvailable() |
|
1196 | { |
|
1197 | 0 | if (getCurrentPageNumber() <= 1) |
1198 | { |
|
1199 | 0 | return false; |
1200 | } |
|
1201 | 0 | return true; |
1202 | } |
|
1203 | ||
1204 | /** |
|
1205 | * Indicates if any results are available. |
|
1206 | * |
|
1207 | * @return <code>true</code> of any results are available. |
|
1208 | */ |
|
1209 | public boolean hasResultsAvailable() |
|
1210 | { |
|
1211 | 0 | return getTotalRecords() > 0; |
1212 | } |
|
1213 | ||
1214 | /** |
|
1215 | * Clear the query result so that the query is reexecuted when the next page |
|
1216 | * is retrieved. You may want to invoke this method if you are returning to |
|
1217 | * a page after performing an operation on an item in the result set. |
|
1218 | * |
|
1219 | * @throws TorqueException if a sleep is interrupted. |
|
1220 | */ |
|
1221 | public synchronized void invalidateResult() throws TorqueException |
|
1222 | { |
|
1223 | 0 | stopQuery(); |
1224 | 0 | blockBegin = 0; |
1225 | 0 | blockEnd = 0; |
1226 | 0 | currentlyFilledTo = -1; |
1227 | 0 | results = null; |
1228 | // TODO Perhaps store the oldPosition and immediately restart the |
|
1229 | // query. |
|
1230 | // oldPosition = position; |
|
1231 | 0 | position = 0; |
1232 | 0 | totalPages = -1; |
1233 | 0 | totalRecords = 0; |
1234 | 0 | queryCompleted = false; |
1235 | 0 | totalsFinalized = false; |
1236 | 0 | lastResults = null; |
1237 | 0 | } |
1238 | ||
1239 | /** |
|
1240 | * Retrieve a search parameter. This acts as a convenient place to store |
|
1241 | * parameters that relate to the LargeSelect to make it easy to get at them |
|
1242 | * in order to repopulate search parameters on a form when the next page of |
|
1243 | * results is retrieved - they in no way effect the operation of |
|
1244 | * LargeSelect. |
|
1245 | * |
|
1246 | * @param name the search parameter key to retrieve. |
|
1247 | * @return the value of the search parameter. |
|
1248 | */ |
|
1249 | public String getSearchParam(String name) |
|
1250 | { |
|
1251 | 0 | return getSearchParam(name, null); |
1252 | } |
|
1253 | ||
1254 | /** |
|
1255 | * Retrieve a search parameter. This acts as a convenient place to store |
|
1256 | * parameters that relate to the LargeSelect to make it easy to get at them |
|
1257 | * in order to repopulate search parameters on a form when the next page of |
|
1258 | * results is retrieved - they in no way effect the operation of |
|
1259 | * LargeSelect. |
|
1260 | * |
|
1261 | * @param name the search parameter key to retrieve. |
|
1262 | * @param defaultValue the default value to return if the key is not found. |
|
1263 | * @return the value of the search parameter. |
|
1264 | */ |
|
1265 | public String getSearchParam(String name, String defaultValue) |
|
1266 | { |
|
1267 | 0 | if (null == params) |
1268 | { |
|
1269 | 0 | return defaultValue; |
1270 | } |
|
1271 | 0 | String value = (String) params.get(name); |
1272 | 0 | return null == value ? defaultValue : value; |
1273 | } |
|
1274 | ||
1275 | /** |
|
1276 | * Set a search parameter. If the value is <code>null</code> then the |
|
1277 | * key will be removed from the parameters. |
|
1278 | * |
|
1279 | * @param name the search parameter key to set. |
|
1280 | * @param value the value of the search parameter to store. |
|
1281 | */ |
|
1282 | public void setSearchParam(String name, String value) |
|
1283 | { |
|
1284 | 0 | if (null == value) |
1285 | { |
|
1286 | 0 | removeSearchParam(name); |
1287 | } |
|
1288 | else |
|
1289 | { |
|
1290 | 0 | if (null != name) |
1291 | { |
|
1292 | 0 | if (null == params) |
1293 | { |
|
1294 | 0 | params = new Hashtable(); |
1295 | } |
|
1296 | 0 | params.put(name, value); |
1297 | } |
|
1298 | } |
|
1299 | 0 | } |
1300 | ||
1301 | /** |
|
1302 | * Remove a value from the search parameters. |
|
1303 | * |
|
1304 | * @param name the search parameter key to remove. |
|
1305 | */ |
|
1306 | public void removeSearchParam(String name) |
|
1307 | { |
|
1308 | 0 | if (null != params) |
1309 | { |
|
1310 | 0 | params.remove(name); |
1311 | } |
|
1312 | 0 | } |
1313 | ||
1314 | /** |
|
1315 | * Deserialize this LargeSelect instance. |
|
1316 | * |
|
1317 | * @param inputStream The serialization input stream. |
|
1318 | * @throws IOException |
|
1319 | * @throws ClassNotFoundException |
|
1320 | */ |
|
1321 | private void readObject(ObjectInputStream inputStream) |
|
1322 | throws IOException, ClassNotFoundException |
|
1323 | { |
|
1324 | 0 | inputStream.defaultReadObject(); |
1325 | ||
1326 | // avoid NPE because of Tomcat de-serialization of sessions |
|
1327 | 0 | if (Torque.isInit()) |
1328 | { |
|
1329 | 0 | startQuery(pageSize); |
1330 | } |
|
1331 | 0 | } |
1332 | ||
1333 | /** |
|
1334 | * Provide something useful for debugging purposes. |
|
1335 | * |
|
1336 | * @return some basic information about this instance of LargeSelect. |
|
1337 | */ |
|
1338 | public String toString() |
|
1339 | { |
|
1340 | 0 | StringBuffer result = new StringBuffer(); |
1341 | 0 | result.append("LargeSelect - TotalRecords: "); |
1342 | 0 | result.append(getTotalRecords()); |
1343 | 0 | result.append(" TotalsFinalised: "); |
1344 | 0 | result.append(getTotalsFinalized()); |
1345 | 0 | result.append("\nParameters:"); |
1346 | 0 | if (null == params || params.size() == 0) |
1347 | { |
|
1348 | 0 | result.append(" No parameters have been set."); |
1349 | } |
|
1350 | else |
|
1351 | { |
|
1352 | 0 | Set keys = params.keySet(); |
1353 | 0 | for (Iterator iter = keys.iterator(); iter.hasNext();) |
1354 | { |
|
1355 | 0 | String key = (String) iter.next(); |
1356 | 0 | String val = (String) params.get(key); |
1357 | 0 | result.append("\n ").append(key).append(": ").append(val); |
1358 | } |
|
1359 | } |
|
1360 | 0 | return result.toString(); |
1361 | } |
|
1362 | ||
1363 | } |
This report is generated by jcoverage, Maven and Maven JCoverage Plugin. |