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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 | * Copyright 2001-2005 The Apache Software Foundation. |
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5 | * |
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6 | * Licensed under the Apache License, Version 2.0 (the "License") |
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7 | * you may not use this file except in compliance with the License. |
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8 | * You may obtain a copy of the License at |
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9 | * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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11 | * |
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12 | * Unless required by applicable law or agreed to in writing, software |
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13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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15 | * See the License for the specific language governing permissions and |
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16 | * limitations under the License. |
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17 | */ |
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18 | ||
19 | import java.io.IOException; |
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20 | import java.io.ObjectInputStream; |
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21 | import java.io.Serializable; |
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22 | import java.lang.reflect.Method; |
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23 | import java.sql.Connection; |
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24 | import java.sql.SQLException; |
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25 | import java.util.ArrayList; |
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26 | import java.util.Hashtable; |
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27 | import java.util.Iterator; |
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28 | import java.util.List; |
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29 | import java.util.Set; |
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30 | ||
31 | import org.apache.commons.logging.Log; |
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32 | import org.apache.commons.logging.LogFactory; |
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33 | import org.apache.torque.Torque; |
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34 | import org.apache.torque.TorqueException; |
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35 | import org.apache.torque.adapter.DB; |
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36 | ||
37 | import com.workingdogs.village.DataSetException; |
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38 | import com.workingdogs.village.QueryDataSet; |
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39 | ||
40 | /** |
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41 | * This class can be used to retrieve a large result set from a database query. |
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42 | * The query is started and then rows are returned a page at a time. The <code> |
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43 | * LargeSelect</code> is meant to be placed into the Session or User.Temp, so |
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44 | * that it can be used in response to several related requests. Note that in |
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45 | * order to use <code>LargeSelect</code> you need to be willing to accept the |
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46 | * fact that the result set may become inconsistent with the database if updates |
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47 | * are processed subsequent to the queries being executed. Specifying a memory |
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48 | * page limit of 1 will give you a consistent view of the records but the totals |
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49 | * may not be accurate and the performance will be terrible. In most cases |
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50 | * the potential for inconsistencies data should not cause any serious problems |
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51 | * and performance should be pretty good (but read on for further warnings). |
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52 | * |
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53 | * <p>The idea here is that the full query result would consume too much memory |
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54 | * and if displayed to a user the page would be too long to be useful. Rather |
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55 | * than loading the full result set into memory, a window of data (the memory |
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56 | * limit) is loaded and retrieved a page at a time. If a request occurs for |
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57 | * data that falls outside the currently loaded window of data then a new query |
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58 | * is executed to fetch the required data. Performance is optimized by |
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59 | * starting a thread to execute the database query and fetch the results. This |
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60 | * will perform best when paging forwards through the data, but a minor |
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61 | * optimization where the window is moved backwards by two rather than one page |
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62 | * is included for when a user pages past the beginning of the window. |
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63 | * |
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64 | * <p>As the query is performed in in steps, it is often the case that the total |
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65 | * number of records and pages of data is unknown. <code>LargeSelect</code> |
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66 | * provides various methods for indicating how many records and pages it is |
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67 | * currently aware of and for presenting this information to users. |
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68 | * |
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69 | * <p><code>LargeSelect</code> utilises the <code>Criteria</code> methods |
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70 | * <code>setOffset()</code> and <code>setLimit()</code> to limit the amount of |
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71 | * data retrieved from the database - these values are either passed through to |
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72 | * the DBMS when supported (efficient with the caveat below) or handled by |
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73 | * the Village API when it is not (not so efficient). At time of writing |
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74 | * <code>Criteria</code> will only pass the offset and limit through to MySQL |
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75 | * and PostgreSQL (with a few changes to <code>DBOracle</code> and <code> |
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76 | * BasePeer</code> Oracle support can be implemented by utilising the <code> |
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77 | * rownum</code> pseudo column). |
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78 | * |
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79 | * <p>As <code>LargeSelect</code> must re-execute the query each time the user |
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80 | * pages out of the window of loaded data, you should consider the impact of |
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81 | * non-index sort orderings and other criteria that will require the DBMS to |
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82 | * execute the entire query before filtering down to the offset and limit either |
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83 | * internally or via Village. |
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84 | * |
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85 | * <p>The memory limit defaults to 5 times the page size you specify, but |
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86 | * alternative constructors and the class method <code>setMemoryPageLimit() |
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87 | * </code> allow you to override this for a specific instance of |
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88 | * <code>LargeSelect</code> or future instances respectively. |
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89 | * |
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90 | * <p>Some of the constructors allow you to specify the name of the class to use |
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91 | * to build the returnd rows. This works by using reflection to find <code> |
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92 | * addSelectColumns(Criteria)</code> and <code>populateObjects(List)</code> |
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93 | * methods to add the necessary select columns to the criteria (only if it |
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94 | * doesn't already contain any) and to convert query results from Village |
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95 | * <code>Record</code> objects to a class defined within the builder class. |
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96 | * This allows you to use any of the Torque generated Peer classes, but also |
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97 | * makes it fairly simple to construct business object classes that can be used |
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98 | * for this purpose (simply copy and customise the <code>addSelectColumns() |
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99 | * </code>, <code>populateObjects()</code>, <code>row2Object()</code> and <code> |
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100 | * populateObject()</code> methods from an existing Peer class). |
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101 | * |
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102 | * <p>Typically you will create a <code>LargeSelect</code> using your <code> |
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103 | * Criteria</code> (perhaps created from the results of a search parameter |
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104 | * page), page size, memory page limit and return class name (for which you may |
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105 | * have defined a business object class before hand) and place this in user.Temp |
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106 | * thus: |
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107 | * |
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108 | * <pre> |
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109 | * data.getUser().setTemp("someName", largeSelect); |
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110 | * </pre> |
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111 | * |
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112 | * <p>In your template you will then use something along the lines of: |
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113 | * |
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114 | * <pre> |
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115 | * #set($largeSelect = $data.User.getTemp("someName")) |
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116 | * #set($searchop = $data.Parameters.getString("searchop")) |
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117 | * #if($searchop.equals("prev")) |
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118 | * #set($recs = $largeSelect.PreviousResults) |
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119 | * #else |
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120 | * #if($searchop.equals("goto")) |
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121 | * #set($recs = $largeSelect.getPage($data.Parameters.getInt("page", 1))) |
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122 | * #else |
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123 | * #set($recs = $largeSelect.NextResults) |
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124 | * #end |
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125 | * #end |
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126 | * </pre> |
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127 | * |
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128 | * <p>...to move through the records. <code>LargeSelect</code> implements a |
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129 | * number of convenience methods that make it easy to add all of the necessary |
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130 | * bells and whistles to your template. |
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131 | * |
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132 | * @author <a href="mailto:john.mcnally@clearink.com">John D. McNally</a> |
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133 | * @author <a href="mailto:seade@backstagetech.com.au">Scott Eade</a> |
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134 | * @version $Id: LargeSelect.java 280639 2005-09-13 20:17:34Z tfischer $ |
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135 | */ |
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136 | public class LargeSelect implements Runnable, Serializable |
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137 | { |
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138 | /** The number of records that a page consists of. */ |
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139 | private int pageSize; |
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140 | /** The maximum number of records to maintain in memory. */ |
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141 | private int memoryLimit; |
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142 | ||
143 | /** The record number of the first record in memory. */ |
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144 | 0 | private transient int blockBegin = 0; |
145 | /** The record number of the last record in memory. */ |
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146 | private transient int blockEnd; |
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147 | /** How much of the memory block is currently occupied with result data. */ |
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148 | 0 | private volatile int currentlyFilledTo = -1; |
149 | ||
150 | /** The SQL query that this <code>LargeSelect</code> represents. */ |
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151 | private String query; |
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152 | /** The database name to get from Torque. */ |
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153 | private String dbName; |
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154 | ||
155 | /** The memory store of records. */ |
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156 | 0 | private transient List results = null; |
157 | ||
158 | /** The thread that executes the query. */ |
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159 | 0 | private transient Thread thread = null; |
160 | /** |
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161 | * A flag used to kill the thread when the currently executing query is no |
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162 | * longer required. |
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163 | */ |
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164 | 0 | private transient volatile boolean killThread = false; |
165 | /** A flag that indicates whether or not the query thread is running. */ |
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166 | 0 | private transient volatile boolean threadRunning = false; |
167 | /** |
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168 | * An indication of whether or not the current query has completed |
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169 | * processing. |
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170 | */ |
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171 | 0 | private transient volatile boolean queryCompleted = false; |
172 | /** |
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173 | * An indication of whether or not the totals (records and pages) are at |
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174 | * their final values. |
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175 | */ |
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176 | 0 | private transient boolean totalsFinalized = false; |
177 | ||
178 | /** The cursor position in the result set. */ |
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179 | private int position; |
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180 | /** The total number of pages known to exist. */ |
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181 | 0 | private int totalPages = -1; |
182 | /** The total number of records known to exist. */ |
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183 | 0 | private int totalRecords = 0; |
184 | ||
185 | /** The criteria used for the query. */ |
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186 | 0 | private Criteria criteria = null; |
187 | /** The last page of results that were returned. */ |
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188 | private transient List lastResults; |
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189 | ||
190 | /** |
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191 | * The class that is possibly used to construct the criteria and used |
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192 | * to transform the Village Records into the desired OM or business objects. |
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193 | */ |
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194 | 0 | private Class returnBuilderClass = null; |
195 | /** |
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196 | * A reference to the method in the return builder class that will |
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197 | * convert the Village Records to the desired class. |
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198 | */ |
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199 | 0 | private transient Method populateObjectsMethod = null; |
200 | ||
201 | /** |
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202 | * The default value (">") used to indicate that the total number of |
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203 | * records or pages is unknown. |
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204 | */ |
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205 | public static final String DEFAULT_MORE_INDICATOR = ">"; |
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206 | ||
207 | /** |
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208 | * The value used to indicate that the total number of records or pages is |
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209 | * unknown (default: ">"). You can use <code>setMoreIndicator()</code> |
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210 | * to change this to whatever value you like (e.g. "more than"). |
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211 | */ |
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212 | 0 | private static String moreIndicator = DEFAULT_MORE_INDICATOR; |
213 | ||
214 | /** |
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215 | * The default value for the maximum number of pages of data to be retained |
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216 | * in memory. |
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217 | */ |
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218 | public static final int DEFAULT_MEMORY_LIMIT_PAGES = 5; |
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219 | ||
220 | /** |
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221 | * The maximum number of pages of data to be retained in memory. Use |
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222 | * <code>setMemoryPageLimit()</code> to provide your own value. |
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223 | */ |
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224 | 0 | private static int memoryPageLimit = DEFAULT_MEMORY_LIMIT_PAGES; |
225 | ||
226 | /** A place to store search parameters that relate to this query. */ |
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227 | 0 | private Hashtable params = null; |
228 | ||
229 | /** Logging */ |
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230 | 0 | private static Log log = LogFactory.getLog(LargeSelect.class); |
231 | ||
232 | /** |
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233 | * Creates a LargeSelect whose results are returned as a <code>List</code> |
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234 | * containing a maximum of <code>pageSize</code> Village <code>Record</code> |
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235 | * objects at a time, maintaining a maximum of |
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236 | * <code>LargeSelect.memoryPageLimit</code> pages of results in memory. |
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237 | * |
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238 | * @param criteria object used by BasePeer to build the query. In order to |
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239 | * allow this class to utilise database server implemented offsets and |
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240 | * limits (when available), the provided criteria must not have any limit or |
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241 | * offset defined. |
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242 | * @param pageSize number of rows to return in one block. |
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243 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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244 | * both of offset and limit, or if <code>pageSize</code> is less than 1; |
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245 | */ |
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246 | public LargeSelect(Criteria criteria, int pageSize) |
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247 | throws IllegalArgumentException |
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248 | { |
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249 | 0 | this(criteria, pageSize, LargeSelect.memoryPageLimit); |
250 | 0 | } |
251 | ||
252 | /** |
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253 | * Creates a LargeSelect whose results are returned as a <code>List</code> |
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254 | * containing a maximum of <code>pageSize</code> Village <code>Record</code> |
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255 | * objects at a time, maintaining a maximum of <code>memoryPageLimit</code> |
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256 | * pages of results in memory. |
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257 | * |
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258 | * @param criteria object used by BasePeer to build the query. In order to |
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259 | * allow this class to utilise database server implemented offsets and |
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260 | * limits (when available), the provided criteria must not have any limit or |
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261 | * offset defined. |
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262 | * @param pageSize number of rows to return in one block. |
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263 | * @param memoryPageLimit maximum number of pages worth of rows to be held |
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264 | * in memory at one time. |
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265 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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266 | * both of offset and limit, or if <code>pageSize</code> or |
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267 | * <code>memoryLimitPages</code> are less than 1; |
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268 | */ |
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269 | public LargeSelect(Criteria criteria, int pageSize, class="keyword">int memoryPageLimit) |
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270 | throws IllegalArgumentException |
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271 | 0 | { |
272 | 0 | init(criteria, pageSize, memoryPageLimit); |
273 | 0 | } |
274 | ||
275 | /** |
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276 | * Creates a LargeSelect whose results are returned as a <code>List</code> |
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277 | * containing a maximum of <code>pageSize</code> objects of the type |
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278 | * defined within the class named <code>returnBuilderClassName</code> at a |
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279 | * time, maintaining a maximum of <code>LargeSelect.memoryPageLimit</code> |
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280 | * pages of results in memory. |
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281 | * |
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282 | * @param criteria object used by BasePeer to build the query. In order to |
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283 | * allow this class to utilise database server implemented offsets and |
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284 | * limits (when available), the provided criteria must not have any limit or |
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285 | * offset defined. If the criteria does not include the definition of any |
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286 | * select columns the <code>addSelectColumns(Criteria)</code> method of |
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287 | * the class named as <code>returnBuilderClassName</code> will be used to |
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288 | * add them. |
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289 | * @param pageSize number of rows to return in one block. |
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290 | * @param returnBuilderClassName The name of the class that will be used to |
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291 | * build the result records (may implement <code>addSelectColumns(Criteria) |
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292 | * </code> and must implement <code>populateObjects(List)</code>). |
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293 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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294 | * both of offset and limit, if <code>pageSize</code> is less than 1, or if |
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295 | * problems are experienced locating and invoking either one or both of |
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296 | * <code>addSelectColumns(Criteria)</code> and <code> populateObjects(List) |
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297 | * </code> in the class named <code>returnBuilderClassName</code>. |
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298 | */ |
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299 | public LargeSelect( |
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300 | Criteria criteria, |
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301 | int pageSize, |
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302 | String returnBuilderClassName) |
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303 | throws IllegalArgumentException |
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304 | { |
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305 | 0 | this( |
306 | criteria, |
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307 | pageSize, |
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308 | LargeSelect.memoryPageLimit, |
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309 | returnBuilderClassName); |
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310 | 0 | } |
311 | ||
312 | /** |
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313 | * Creates a LargeSelect whose results are returned as a <code>List</code> |
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314 | * containing a maximum of <code>pageSize</code> objects of the type |
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315 | * defined within the class named <code>returnBuilderClassName</code> at a |
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316 | * time, maintaining a maximum of <code>memoryPageLimit</code> pages of |
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317 | * results in memory. |
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318 | * |
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319 | * @param criteria object used by BasePeer to build the query. In order to |
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320 | * allow this class to utilise database server implemented offsets and |
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321 | * limits (when available), the provided criteria must not have any limit or |
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322 | * offset defined. If the criteria does not include the definition of any |
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323 | * select columns the <code>addSelectColumns(Criteria)</code> method of |
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324 | * the class named as <code>returnBuilderClassName</code> will be used to |
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325 | * add them. |
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326 | * @param pageSize number of rows to return in one block. |
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327 | * @param memoryPageLimit maximum number of pages worth of rows to be held |
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328 | * in memory at one time. |
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329 | * @param returnBuilderClassName The name of the class that will be used to |
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330 | * build the result records (may implement <code>addSelectColumns(Criteria) |
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331 | * </code> and must implement <code>populateObjects(List)</code>). |
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332 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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333 | * both of offset and limit, if <code>pageSize</code> or <code> |
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334 | * memoryLimitPages</code> are less than 1, or if problems are experienced |
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335 | * locating and invoking either one or both of <code> |
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336 | * addSelectColumns(Criteria)</code> and <code> populateObjects(List)</code> |
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337 | * in the class named <code>returnBuilderClassName</code>. |
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338 | */ |
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339 | public LargeSelect( |
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340 | Criteria criteria, |
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341 | int pageSize, |
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342 | int memoryPageLimit, |
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343 | String returnBuilderClassName) |
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344 | throws IllegalArgumentException |
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345 | 0 | { |
346 | try |
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347 | { |
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348 | 0 | this.returnBuilderClass = Class.forName(returnBuilderClassName); |
349 | ||
350 | // Add the select columns if necessary. |
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351 | 0 | if (criteria.getSelectColumns().size() == 0) |
352 | { |
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353 | 0 | Class[] argTypes = { Criteria.class }; |
354 | 0 | Method selectColumnAdder = |
355 | returnBuilderClass.getMethod("addSelectColumns", argTypes); |
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356 | 0 | Object[] theArgs = { criteria }; |
357 | 0 | selectColumnAdder.invoke(returnBuilderClass.newInstance(), |
358 | theArgs); |
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359 | } |
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360 | } |
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361 | 0 | catch (Exception e) |
362 | { |
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363 | 0 | throw new IllegalArgumentException( |
364 | "The class named as returnBuilderClassName does not " |
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365 | + "provide the necessary facilities - see javadoc."); |
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366 | 0 | } |
367 | ||
368 | 0 | init(criteria, pageSize, memoryPageLimit); |
369 | 0 | } |
370 | ||
371 | /** |
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372 | * Access the populateObjects method. |
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373 | */ |
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374 | private Method getPopulateObjectsMethod() |
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375 | throws SecurityException, NoSuchMethodException |
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376 | { |
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377 | 0 | if (null == populateObjectsMethod) |
378 | { |
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379 | 0 | Class[] argTypes = { List.class }; |
380 | 0 | populateObjectsMethod |
381 | = returnBuilderClass.getMethod("populateObjects", argTypes); |
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382 | } |
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383 | 0 | return populateObjectsMethod; |
384 | } |
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385 | ||
386 | /** |
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387 | * Called by the constructors to start the query. |
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388 | * |
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389 | * @param criteria Object used by <code>BasePeer</code> to build the query. |
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390 | * In order to allow this class to utilise database server implemented |
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391 | * offsets and limits (when available), the provided criteria must not have |
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392 | * any limit or offset defined. |
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393 | * @param pageSize number of rows to return in one block. |
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394 | * @param memoryLimitPages maximum number of pages worth of rows to be held |
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395 | * in memory at one time. |
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396 | * @throws IllegalArgumentException if <code>criteria</code> uses one or |
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397 | * both of offset and limit and if <code>pageSize</code> or |
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398 | * <code>memoryLimitPages</code> are less than 1; |
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399 | */ |
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400 | private void init(Criteria criteria, int pageSize, class="keyword">int memoryLimitPages) |
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401 | throws IllegalArgumentException |
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402 | { |
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403 | 0 | if (criteria.getOffset() != 0 || criteria.getLimit() != -1) |
404 | { |
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405 | 0 | throw new IllegalArgumentException( |
406 | "criteria must not use Offset and/or Limit."); |
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407 | } |
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408 | ||
409 | 0 | if (pageSize < 1) |
410 | { |
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411 | 0 | throw new IllegalArgumentException( |
412 | "pageSize must be greater than zero."); |
|
413 | } |
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414 | ||
415 | 0 | if (memoryLimitPages < 1) |
416 | { |
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417 | 0 | throw new IllegalArgumentException( |
418 | "memoryPageLimit must be greater than zero."); |
|
419 | } |
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420 | ||
421 | 0 | this.pageSize = pageSize; |
422 | 0 | this.memoryLimit = pageSize * memoryLimitPages; |
423 | 0 | this.criteria = criteria; |
424 | 0 | dbName = criteria.getDbName(); |
425 | 0 | blockEnd = blockBegin + memoryLimit - 1; |
426 | 0 | startQuery(pageSize); |
427 | 0 | } |
428 | ||
429 | /** |
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430 | * Retrieve a specific page, if it exists. |
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431 | * |
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432 | * @param pageNumber the number of the page to be retrieved - must be |
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433 | * greater than zero. An empty <code>List</code> will be returned if |
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434 | * <code>pageNumber</code> exceeds the total number of pages that exist. |
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435 | * @return a <code>List</code> of query results containing a maximum of |
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436 | * <code>pageSize</code> results. |
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437 | * @throws IllegalArgumentException when <code>pageNo</code> is not |
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438 | * greater than zero. |
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439 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
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440 | * method runs into problems or a sleep is unexpectedly interrupted. |
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441 | */ |
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442 | public List getPage(int pageNumber) throws TorqueException |
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443 | { |
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444 | 0 | if (pageNumber < 1) |
445 | { |
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446 | 0 | throw new IllegalArgumentException( |
447 | "pageNumber must be greater than zero."); |
|
448 | } |
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449 | 0 | return getResults((pageNumber - 1) * pageSize); |
450 | } |
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451 | ||
452 | /** |
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453 | * Gets the next page of rows. |
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454 | * |
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455 | * @return a <code>List</code> of query results containing a maximum of |
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456 | * <code>pageSize</code> reslts. |
|
457 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
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458 | * method runs into problems or a sleep is unexpectedly interrupted. |
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459 | */ |
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460 | public List getNextResults() throws TorqueException |
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461 | { |
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462 | 0 | if (!getNextResultsAvailable()) |
463 | { |
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464 | 0 | return getCurrentPageResults(); |
465 | } |
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466 | 0 | return getResults(position); |
467 | } |
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468 | ||
469 | /** |
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470 | * Provide access to the results from the current page. |
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471 | * |
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472 | * @return a <code>List</code> of query results containing a maximum of |
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473 | * <code>pageSize</code> reslts. |
|
474 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
475 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
476 | */ |
|
477 | public List getCurrentPageResults() throws TorqueException |
|
478 | { |
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479 | 0 | return null == lastResults && position > 0 |
480 | ? getResults(position) : lastResults; |
|
481 | } |
|
482 | ||
483 | /** |
|
484 | * Gets the previous page of rows. |
|
485 | * |
|
486 | * @return a <code>List</code> of query results containing a maximum of |
|
487 | * <code>pageSize</code> reslts. |
|
488 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
489 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
490 | */ |
|
491 | public List getPreviousResults() throws TorqueException |
|
492 | { |
|
493 | 0 | if (!getPreviousResultsAvailable()) |
494 | { |
|
495 | 0 | return getCurrentPageResults(); |
496 | } |
|
497 | ||
498 | int start; |
|
499 | 0 | if (position - 2 * pageSize < 0) |
500 | { |
|
501 | 0 | start = 0; |
502 | } |
|
503 | else |
|
504 | { |
|
505 | 0 | start = position - 2 * pageSize; |
506 | } |
|
507 | 0 | return getResults(start); |
508 | } |
|
509 | ||
510 | /** |
|
511 | * Gets a page of rows starting at a specified row. |
|
512 | * |
|
513 | * @param start the starting row. |
|
514 | * @return a <code>List</code> of query results containing a maximum of |
|
515 | * <code>pageSize</code> reslts. |
|
516 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
517 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
518 | */ |
|
519 | private List getResults(int start) throws TorqueException |
|
520 | { |
|
521 | 0 | return getResults(start, pageSize); |
522 | } |
|
523 | ||
524 | /** |
|
525 | * Gets a block of rows starting at a specified row and containing a |
|
526 | * specified number of rows. |
|
527 | * |
|
528 | * @param start the starting row. |
|
529 | * @param size the number of rows. |
|
530 | * @return a <code>List</code> of query results containing a maximum of |
|
531 | * <code>pageSize</code> reslts. |
|
532 | * @throws IllegalArgumentException if <code>size > memoryLimit</code> or |
|
533 | * <code>start</code> and <code>size</code> result in a situation that is |
|
534 | * not catered for. |
|
535 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
536 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
537 | */ |
|
538 | private synchronized List getResults(int start, class="keyword">int size) |
|
539 | throws IllegalArgumentException, TorqueException |
|
540 | { |
|
541 | 0 | if (log.isDebugEnabled()) |
542 | { |
|
543 | 0 | log.debug("getResults(start: " + start |
544 | + ", size: " + size + ") invoked."); |
|
545 | } |
|
546 | ||
547 | 0 | if (size > memoryLimit) |
548 | { |
|
549 | 0 | throw new IllegalArgumentException("size (" + size |
550 | + ") exceeds memory limit (" + memoryLimit + ")."); |
|
551 | } |
|
552 | ||
553 | // Request was for a block of rows which should be in progess. |
|
554 | // If the rows have not yet been returned, wait for them to be |
|
555 | // retrieved. |
|
556 | 0 | if (start >= blockBegin && (start + size - 1) <= blockEnd) |
557 | { |
|
558 | 0 | if (log.isDebugEnabled()) |
559 | { |
|
560 | 0 | log.debug("getResults(): Sleeping until " |
561 | + "start+size-1 (" + (start + size - 1) |
|
562 | + ") > currentlyFilledTo (" + currentlyFilledTo |
|
563 | + ") && !queryCompleted (!" + queryCompleted + ")"); |
|
564 | } |
|
565 | 0 | while (((start + size - 1) > currentlyFilledTo) && !queryCompleted) |
566 | { |
|
567 | try |
|
568 | { |
|
569 | 0 | Thread.sleep(500); |
570 | } |
|
571 | 0 | catch (InterruptedException e) |
572 | { |
|
573 | 0 | throw new TorqueException("Unexpected interruption", e); |
574 | 0 | } |
575 | } |
|
576 | } |
|
577 | ||
578 | // Going in reverse direction, trying to limit db hits so assume user |
|
579 | // might want at least 2 sets of data. |
|
580 | 0 | else if (start < blockBegin && start >= 0) |
581 | { |
|
582 | 0 | if (log.isDebugEnabled()) |
583 | { |
|
584 | 0 | log.debug("getResults(): Paging backwards as start (" + start |
585 | + ") < blockBegin (" + blockBegin + ") && start >= 0"); |
|
586 | } |
|
587 | 0 | stopQuery(); |
588 | 0 | if (memoryLimit >= 2 * size) |
589 | { |
|
590 | 0 | blockBegin = start - size; |
591 | 0 | if (blockBegin < 0) |
592 | { |
|
593 | 0 | blockBegin = 0; |
594 | } |
|
595 | } |
|
596 | else |
|
597 | { |
|
598 | 0 | blockBegin = start; |
599 | } |
|
600 | 0 | blockEnd = blockBegin + memoryLimit - 1; |
601 | 0 | startQuery(size); |
602 | // Re-invoke getResults() to provide the wait processing. |
|
603 | 0 | return getResults(start, size); |
604 | } |
|
605 | ||
606 | // Assume we are moving on, do not retrieve any records prior to start. |
|
607 | 0 | else if ((start + size - 1) > blockEnd) |
608 | { |
|
609 | 0 | if (log.isDebugEnabled()) |
610 | { |
|
611 | 0 | log.debug("getResults(): Paging past end of loaded data as " |
612 | + "start+size-1 (" + (start + size - 1) |
|
613 | + ") > blockEnd (" + blockEnd + ")"); |
|
614 | } |
|
615 | 0 | stopQuery(); |
616 | 0 | blockBegin = start; |
617 | 0 | blockEnd = blockBegin + memoryLimit - 1; |
618 | 0 | startQuery(size); |
619 | // Re-invoke getResults() to provide the wait processing. |
|
620 | 0 | return getResults(start, size); |
621 | } |
|
622 | ||
623 | else |
|
624 | { |
|
625 | 0 | throw new IllegalArgumentException("Parameter configuration not " |
626 | + "accounted for."); |
|
627 | } |
|
628 | ||
629 | 0 | int fromIndex = start - blockBegin; |
630 | 0 | int toIndex = fromIndex + Math.min(size, results.size() - fromIndex); |
631 | ||
632 | 0 | if (log.isDebugEnabled()) |
633 | { |
|
634 | 0 | log.debug("getResults(): Retrieving records from results elements " |
635 | + "start-blockBegin (" + fromIndex + ") through " |
|
636 | + "fromIndex + Math.min(size, results.size() - fromIndex) (" |
|
637 | + toIndex + ")"); |
|
638 | } |
|
639 | ||
640 | List returnResults; |
|
641 | ||
642 | 0 | synchronized (results) |
643 | { |
|
644 | 0 | returnResults = new ArrayList(results.subList(fromIndex, toIndex)); |
645 | 0 | } |
646 | ||
647 | 0 | if (null != returnBuilderClass) |
648 | { |
|
649 | // Invoke the populateObjects() method |
|
650 | 0 | Object[] theArgs = { returnResults }; |
651 | try |
|
652 | { |
|
653 | 0 | returnResults = (List) getPopulateObjectsMethod().invoke( |
654 | returnBuilderClass.newInstance(), theArgs); |
|
655 | } |
|
656 | 0 | catch (Exception e) |
657 | { |
|
658 | 0 | throw new TorqueException("Unable to populate results", e); |
659 | 0 | } |
660 | } |
|
661 | 0 | position = start + size; |
662 | 0 | lastResults = returnResults; |
663 | 0 | return class="keyword">returnResults; |
664 | } |
|
665 | ||
666 | /** |
|
667 | * A background thread that retrieves the rows. |
|
668 | */ |
|
669 | public void run() |
|
670 | { |
|
671 | boolean dbSupportsNativeLimit; |
|
672 | try |
|
673 | { |
|
674 | 0 | dbSupportsNativeLimit |
675 | = (Torque.getDB(dbName).getLimitStyle() |
|
676 | != DB.LIMIT_STYLE_NONE); |
|
677 | } |
|
678 | 0 | catch (TorqueException e) |
679 | { |
|
680 | 0 | log.error("run() : Exiting :", e); |
681 | // we cannot execute further because Torque is not initialized |
|
682 | // correctly |
|
683 | 0 | return; |
684 | 0 | } |
685 | ||
686 | int size; |
|
687 | 0 | if (dbSupportsNativeLimit) |
688 | { |
|
689 | // retrieve one page at a time |
|
690 | 0 | size = pageSize; |
691 | } |
|
692 | else |
|
693 | { |
|
694 | // retrieve the whole block at once and add the offset, |
|
695 | // and add one record to check if we have reached the end of the |
|
696 | // data |
|
697 | 0 | size = blockBegin + memoryLimit + 1; |
698 | } |
|
699 | /* The connection to the database. */ |
|
700 | 0 | Connection conn = null; |
701 | /** Used to retrieve query results from Village. */ |
|
702 | 0 | QueryDataSet qds = null; |
703 | ||
704 | try |
|
705 | { |
|
706 | // Add 1 to memory limit to check if the query ends on a page break. |
|
707 | 0 | results = new ArrayList(memoryLimit + 1); |
708 | ||
709 | 0 | if (dbSupportsNativeLimit) |
710 | { |
|
711 | // Use the criteria to limit the rows that are retrieved to the |
|
712 | // block of records that fit in the predefined memoryLimit. |
|
713 | 0 | criteria.setOffset(blockBegin); |
714 | // Add 1 to memory limit to check if the query ends on a |
|
715 | // page break. |
|
716 | 0 | criteria.setLimit(memoryLimit + 1); |
717 | } |
|
718 | 0 | query = BasePeer.createQueryString(criteria); |
719 | ||
720 | // Get a connection to the db. |
|
721 | 0 | conn = Torque.getConnection(dbName); |
722 | ||
723 | // Execute the query. |
|
724 | 0 | if (log.isDebugEnabled()) |
725 | { |
|
726 | 0 | log.debug("run(): query = " + query); |
727 | 0 | log.debug("run(): memoryLimit = " + memoryLimit); |
728 | 0 | log.debug("run(): blockBegin = " + blockBegin); |
729 | 0 | log.debug("run(): blockEnd = " + blockEnd); |
730 | } |
|
731 | 0 | qds = new QueryDataSet(conn, query); |
732 | ||
733 | // Continue getting rows one page at a time until the memory limit |
|
734 | // is reached, all results have been retrieved, or the rest |
|
735 | // of the results have been determined to be irrelevant. |
|
736 | while (!killThread |
|
737 | && !qds.allRecordsRetrieved() |
|
738 | 0 | && currentlyFilledTo + pageSize <= blockEnd) |
739 | { |
|
740 | // This caters for when memoryLimit is not a multiple of |
|
741 | // pageSize which it never is because we always add 1 above. |
|
742 | // not applicable if the db has no native limit where this |
|
743 | // was already considered |
|
744 | 0 | if ((currentlyFilledTo + pageSize) >= blockEnd |
745 | && dbSupportsNativeLimit) |
|
746 | { |
|
747 | // Add 1 to check if the query ends on a page break. |
|
748 | 0 | size = blockEnd - currentlyFilledTo + 1; |
749 | } |
|
750 | ||
751 | 0 | if (log.isDebugEnabled()) |
752 | { |
|
753 | 0 | log.debug("run(): Invoking BasePeer.getSelectResults(qds, " |
754 | + size + ", false)"); |
|
755 | } |
|
756 | ||
757 | 0 | List tempResults |
758 | = BasePeer.getSelectResults(qds, size, false); |
|
759 | ||
760 | 0 | synchronized (results) |
761 | { |
|
762 | 0 | for (int i = 0, n = tempResults.size(); i < n; i++) |
763 | { |
|
764 | 0 | if (dbSupportsNativeLimit |
765 | || (i >= blockBegin)) |
|
766 | 0 | results.add(tempResults.get(i)); |
767 | } |
|
768 | 0 | } |
769 | ||
770 | 0 | if (dbSupportsNativeLimit) |
771 | { |
|
772 | 0 | currentlyFilledTo += tempResults.size(); |
773 | } |
|
774 | else |
|
775 | { |
|
776 | 0 | currentlyFilledTo = tempResults.size() - 1 - blockBegin; |
777 | } |
|
778 | ||
779 | 0 | boolean perhapsLastPage = true; |
780 | ||
781 | // If the extra record was indeed found then we know we are not |
|
782 | // on the last page but we must now get rid of it. |
|
783 | 0 | if ((dbSupportsNativeLimit |
784 | && (results.size() == memoryLimit + 1)) |
|
785 | || (!dbSupportsNativeLimit |
|
786 | && currentlyFilledTo >= memoryLimit)) |
|
787 | { |
|
788 | 0 | synchronized (results) |
789 | { |
|
790 | 0 | results.remove(currentlyFilledTo--); |
791 | 0 | } |
792 | 0 | perhapsLastPage = false; |
793 | } |
|
794 | ||
795 | 0 | if (results.size() > 0 |
796 | && blockBegin + currentlyFilledTo >= totalRecords) |
|
797 | { |
|
798 | // Add 1 because index starts at 0 |
|
799 | 0 | totalRecords = blockBegin + currentlyFilledTo + 1; |
800 | } |
|
801 | ||
802 | // if the db has limited the datasets, we must retrieve all |
|
803 | // datasets. If not, we are always finished because we fetch |
|
804 | // the whole block at once. |
|
805 | 0 | if (qds.allRecordsRetrieved() |
806 | || !dbSupportsNativeLimit) |
|
807 | { |
|
808 | 0 | queryCompleted = true; |
809 | // The following ugly condition ensures that the totals are |
|
810 | // not finalized when a user does something like requesting |
|
811 | // a page greater than what exists in the database. |
|
812 | 0 | if (perhapsLastPage |
813 | && getCurrentPageNumber() <= getTotalPages()) |
|
814 | { |
|
815 | 0 | totalsFinalized = true; |
816 | } |
|
817 | } |
|
818 | 0 | qds.clearRecords(); |
819 | } |
|
820 | ||
821 | 0 | if (log.isDebugEnabled()) |
822 | { |
|
823 | 0 | log.debug("run(): While loop terminated because either:"); |
824 | 0 | log.debug("run(): 1. qds.allRecordsRetrieved(): " |
825 | + qds.allRecordsRetrieved()); |
|
826 | 0 | log.debug("run(): 2. killThread: " + killThread); |
827 | 0 | log.debug("run(): 3. !(currentlyFilledTo + size <= blockEnd): !" |
828 | + (currentlyFilledTo + pageSize <= blockEnd)); |
|
829 | 0 | log.debug("run(): - currentlyFilledTo: " + currentlyFilledTo); |
830 | 0 | log.debug("run(): - size: " + pageSize); |
831 | 0 | log.debug("run(): - blockEnd: " + blockEnd); |
832 | 0 | log.debug("run(): - results.size(): " + results.size()); |
833 | } |
|
834 | 0 | } |
835 | 0 | catch (TorqueException e) |
836 | { |
|
837 | 0 | log.error(e); |
838 | 0 | } |
839 | 0 | catch (SQLException e) |
840 | { |
|
841 | 0 | log.error(e); |
842 | 0 | } |
843 | 0 | catch (DataSetException e) |
844 | { |
|
845 | 0 | log.error(e); |
846 | 0 | } |
847 | finally |
|
848 | { |
|
849 | 0 | try |
850 | { |
|
851 | 0 | if (qds != null) |
852 | { |
|
853 | 0 | qds.close(); |
854 | } |
|
855 | 0 | Torque.closeConnection(conn); |
856 | } |
|
857 | 0 | catch (SQLException e) |
858 | { |
|
859 | 0 | log.error(e); |
860 | } |
|
861 | 0 | catch (DataSetException e) |
862 | { |
|
863 | 0 | log.error(e); |
864 | 0 | } |
865 | 0 | threadRunning = false; |
866 | 0 | } |
867 | 0 | } |
868 | ||
869 | /** |
|
870 | * Starts a new thread to retrieve the result set. |
|
871 | * |
|
872 | * @param initialSize the initial size for each block. |
|
873 | */ |
|
874 | private synchronized void startQuery(int initialSize) |
|
875 | { |
|
876 | 0 | if (!threadRunning) |
877 | { |
|
878 | 0 | pageSize = initialSize; |
879 | 0 | currentlyFilledTo = -1; |
880 | 0 | queryCompleted = false; |
881 | 0 | thread = new Thread(this); |
882 | 0 | thread.start(); |
883 | 0 | threadRunning = true; |
884 | } |
|
885 | 0 | } |
886 | ||
887 | /** |
|
888 | * Used to stop filling the memory with the current block of results, if it |
|
889 | * has been determined that they are no longer relevant. |
|
890 | * |
|
891 | * @throws TorqueException if a sleep is interrupted. |
|
892 | */ |
|
893 | private synchronized void stopQuery() throws TorqueException |
|
894 | { |
|
895 | 0 | if (threadRunning) |
896 | { |
|
897 | 0 | killThread = true; |
898 | 0 | while (thread.isAlive()) |
899 | { |
|
900 | try |
|
901 | { |
|
902 | 0 | Thread.sleep(100); |
903 | } |
|
904 | 0 | catch (InterruptedException e) |
905 | { |
|
906 | 0 | throw new TorqueException("Unexpected interruption", e); |
907 | 0 | } |
908 | } |
|
909 | 0 | killThread = false; |
910 | } |
|
911 | 0 | } |
912 | ||
913 | /** |
|
914 | * Retrieve the number of the current page. |
|
915 | * |
|
916 | * @return the current page number. |
|
917 | */ |
|
918 | public int getCurrentPageNumber() |
|
919 | { |
|
920 | 0 | return position / pageSize; |
921 | } |
|
922 | ||
923 | /** |
|
924 | * Retrieve the total number of search result records that are known to |
|
925 | * exist (this will be the actual value when the query has completeted (see |
|
926 | * <code>getTotalsFinalized()</code>). The convenience method |
|
927 | * <code>getRecordProgressText()</code> may be more useful for presenting to |
|
928 | * users. |
|
929 | * |
|
930 | * @return the number of result records known to exist (not accurate until |
|
931 | * <code>getTotalsFinalized()</code> returns <code>true</code>). |
|
932 | */ |
|
933 | public int getTotalRecords() |
|
934 | { |
|
935 | 0 | return totalRecords; |
936 | } |
|
937 | ||
938 | /** |
|
939 | * Provide an indication of whether or not paging of results will be |
|
940 | * required. |
|
941 | * |
|
942 | * @return <code>true</code> when multiple pages of results exist. |
|
943 | */ |
|
944 | public boolean getPaginated() |
|
945 | { |
|
946 | // Handle a page memory limit of 1 page. |
|
947 | 0 | if (!getTotalsFinalized()) |
948 | { |
|
949 | 0 | return true; |
950 | } |
|
951 | 0 | return blockBegin + currentlyFilledTo + 1 > pageSize; |
952 | } |
|
953 | ||
954 | /** |
|
955 | * Retrieve the total number of pages of search results that are known to |
|
956 | * exist (this will be the actual value when the query has completeted (see |
|
957 | * <code>getQyeryCompleted()</code>). The convenience method |
|
958 | * <code>getPageProgressText()</code> may be more useful for presenting to |
|
959 | * users. |
|
960 | * |
|
961 | * @return the number of pages of results known to exist (not accurate until |
|
962 | * <code>getTotalsFinalized()</code> returns <code>true</code>). |
|
963 | */ |
|
964 | public int getTotalPages() |
|
965 | { |
|
966 | 0 | if (totalPages > -1) |
967 | { |
|
968 | 0 | return totalPages; |
969 | } |
|
970 | ||
971 | 0 | int tempPageCount = getTotalRecords() / pageSize |
972 | + (getTotalRecords() % pageSize > 0 ? 1 : 0); |
|
973 | ||
974 | 0 | if (getTotalsFinalized()) |
975 | { |
|
976 | 0 | totalPages = tempPageCount; |
977 | } |
|
978 | ||
979 | 0 | return tempPageCount; |
980 | } |
|
981 | ||
982 | /** |
|
983 | * Retrieve the page size. |
|
984 | * |
|
985 | * @return the number of records returned on each invocation of |
|
986 | * <code>getNextResults()</code>/<code>getPreviousResults()</code>. |
|
987 | */ |
|
988 | public int getPageSize() |
|
989 | { |
|
990 | 0 | return pageSize; |
991 | } |
|
992 | ||
993 | /** |
|
994 | * Provide access to indicator that the total values for the number of |
|
995 | * records and pages are now accurate as opposed to known upper limits. |
|
996 | * |
|
997 | * @return <code>true</code> when the totals are known to have been fully |
|
998 | * computed. |
|
999 | */ |
|
1000 | public boolean getTotalsFinalized() |
|
1001 | { |
|
1002 | 0 | return totalsFinalized; |
1003 | } |
|
1004 | ||
1005 | /** |
|
1006 | * Provide a way of changing the more pages/records indicator. |
|
1007 | * |
|
1008 | * @param moreIndicator the indicator to use in place of the default |
|
1009 | * (">"). |
|
1010 | */ |
|
1011 | public static void setMoreIndicator(String moreIndicator) |
|
1012 | { |
|
1013 | 0 | LargeSelect.moreIndicator = moreIndicator; |
1014 | 0 | } |
1015 | ||
1016 | /** |
|
1017 | * Retrieve the more pages/records indicator. |
|
1018 | */ |
|
1019 | public static String getMoreIndicator() |
|
1020 | { |
|
1021 | 0 | return LargeSelect.moreIndicator; |
1022 | } |
|
1023 | ||
1024 | /** |
|
1025 | * Sets the multiplier that will be used to compute the memory limit when a |
|
1026 | * constructor with no memory page limit is used - the memory limit will be |
|
1027 | * this number multiplied by the page size. |
|
1028 | * |
|
1029 | * @param memoryPageLimit the maximum number of pages to be in memory |
|
1030 | * at one time. |
|
1031 | */ |
|
1032 | public static void setMemoryPageLimit(int memoryPageLimit) |
|
1033 | { |
|
1034 | 0 | LargeSelect.memoryPageLimit = memoryPageLimit; |
1035 | 0 | } |
1036 | ||
1037 | /** |
|
1038 | * Retrieves the multiplier that will be used to compute the memory limit |
|
1039 | * when a constructor with no memory page limit is used - the memory limit |
|
1040 | * will be this number multiplied by the page size. |
|
1041 | */ |
|
1042 | public static int getMemoryPageLimit() |
|
1043 | { |
|
1044 | 0 | return LargeSelect.memoryPageLimit; |
1045 | } |
|
1046 | ||
1047 | /** |
|
1048 | * A convenience method that provides text showing progress through the |
|
1049 | * selected rows on a page basis. |
|
1050 | * |
|
1051 | * @return progress text in the form of "1 of > 5" where ">" can be |
|
1052 | * configured using <code>setMoreIndicator()</code>. |
|
1053 | */ |
|
1054 | public String getPageProgressText() |
|
1055 | { |
|
1056 | 0 | StringBuffer result = new StringBuffer(); |
1057 | 0 | result.append(getCurrentPageNumber()); |
1058 | 0 | result.append(" of "); |
1059 | 0 | if (!totalsFinalized) |
1060 | { |
|
1061 | 0 | result.append(moreIndicator); |
1062 | 0 | result.append(" "); |
1063 | } |
|
1064 | 0 | result.append(getTotalPages()); |
1065 | 0 | return result.toString(); |
1066 | } |
|
1067 | ||
1068 | /** |
|
1069 | * Provides a count of the number of rows to be displayed on the current |
|
1070 | * page - for the last page this may be less than the configured page size. |
|
1071 | * |
|
1072 | * @return the number of records that are included on the current page of |
|
1073 | * results. |
|
1074 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
1075 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
1076 | */ |
|
1077 | public int getCurrentPageSize() throws TorqueException |
|
1078 | { |
|
1079 | 0 | if (null == getCurrentPageResults()) |
1080 | { |
|
1081 | 0 | return 0; |
1082 | } |
|
1083 | 0 | return getCurrentPageResults().size(); |
1084 | } |
|
1085 | ||
1086 | /** |
|
1087 | * Provide the record number of the first row included on the current page. |
|
1088 | * |
|
1089 | * @return The record number of the first row of the current page. |
|
1090 | */ |
|
1091 | public int getFirstRecordNoForPage() |
|
1092 | { |
|
1093 | 0 | if (getCurrentPageNumber() < 1) |
1094 | { |
|
1095 | 0 | return 0; |
1096 | } |
|
1097 | 0 | return (getCurrentPageNumber() - 1) * getPageSize() + 1; |
1098 | } |
|
1099 | ||
1100 | /** |
|
1101 | * Provide the record number of the last row included on the current page. |
|
1102 | * |
|
1103 | * @return the record number of the last row of the current page. |
|
1104 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
1105 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
1106 | */ |
|
1107 | public int getLastRecordNoForPage() throws TorqueException |
|
1108 | { |
|
1109 | 0 | if (0 == getCurrentPageNumber()) |
1110 | { |
|
1111 | 0 | return 0; |
1112 | } |
|
1113 | 0 | return (getCurrentPageNumber() - 1) * getPageSize() |
1114 | + getCurrentPageSize(); |
|
1115 | } |
|
1116 | ||
1117 | /** |
|
1118 | * A convenience method that provides text showing progress through the |
|
1119 | * selected rows on a record basis. |
|
1120 | * |
|
1121 | * @return progress text in the form of "26 - 50 of > 250" where ">" |
|
1122 | * can be configured using <code>setMoreIndicator()</code>. |
|
1123 | * @throws TorqueException if invoking the <code>populateObjects()<code> |
|
1124 | * method runs into problems or a sleep is unexpectedly interrupted. |
|
1125 | */ |
|
1126 | public String getRecordProgressText() throws TorqueException |
|
1127 | { |
|
1128 | 0 | StringBuffer result = new StringBuffer(); |
1129 | 0 | result.append(getFirstRecordNoForPage()); |
1130 | 0 | result.append(" - "); |
1131 | 0 | result.append(getLastRecordNoForPage()); |
1132 | 0 | result.append(" of "); |
1133 | 0 | if (!totalsFinalized) |
1134 | { |
|
1135 | 0 | result.append(moreIndicator); |
1136 | 0 | result.append(" "); |
1137 | } |
|
1138 | 0 | result.append(getTotalRecords()); |
1139 | 0 | return result.toString(); |
1140 | } |
|
1141 | ||
1142 | /** |
|
1143 | * Indicates if further result pages are available. |
|
1144 | * |
|
1145 | * @return <code>true</code> when further results are available. |
|
1146 | */ |
|
1147 | public boolean getNextResultsAvailable() |
|
1148 | { |
|
1149 | 0 | if (!totalsFinalized || getCurrentPageNumber() < getTotalPages()) |
1150 | { |
|
1151 | 0 | return true; |
1152 | } |
|
1153 | 0 | return false; |
1154 | } |
|
1155 | ||
1156 | /** |
|
1157 | * Indicates if previous results pages are available. |
|
1158 | * |
|
1159 | * @return <code>true</code> when previous results are available. |
|
1160 | */ |
|
1161 | public boolean getPreviousResultsAvailable() |
|
1162 | { |
|
1163 | 0 | if (getCurrentPageNumber() <= 1) |
1164 | { |
|
1165 | 0 | return false; |
1166 | } |
|
1167 | 0 | return true; |
1168 | } |
|
1169 | ||
1170 | /** |
|
1171 | * Indicates if any results are available. |
|
1172 | * |
|
1173 | * @return <code>true</code> of any results are available. |
|
1174 | */ |
|
1175 | public boolean hasResultsAvailable() |
|
1176 | { |
|
1177 | 0 | return getTotalRecords() > 0; |
1178 | } |
|
1179 | ||
1180 | /** |
|
1181 | * Clear the query result so that the query is reexecuted when the next page |
|
1182 | * is retrieved. You may want to invoke this method if you are returning to |
|
1183 | * a page after performing an operation on an item in the result set. |
|
1184 | * |
|
1185 | * @throws TorqueException if a sleep is interrupted. |
|
1186 | */ |
|
1187 | public synchronized void invalidateResult() throws TorqueException |
|
1188 | { |
|
1189 | 0 | stopQuery(); |
1190 | 0 | blockBegin = 0; |
1191 | 0 | blockEnd = 0; |
1192 | 0 | currentlyFilledTo = -1; |
1193 | 0 | results = null; |
1194 | // TODO Perhaps store the oldPosition and immediately restart the |
|
1195 | // query. |
|
1196 | // oldPosition = position; |
|
1197 | 0 | position = 0; |
1198 | 0 | totalPages = -1; |
1199 | 0 | totalRecords = 0; |
1200 | 0 | queryCompleted = false; |
1201 | 0 | totalsFinalized = false; |
1202 | 0 | lastResults = null; |
1203 | 0 | } |
1204 | ||
1205 | /** |
|
1206 | * Retrieve a search parameter. This acts as a convenient place to store |
|
1207 | * parameters that relate to the LargeSelect to make it easy to get at them |
|
1208 | * in order to repopulate search parameters on a form when the next page of |
|
1209 | * results is retrieved - they in no way effect the operation of |
|
1210 | * LargeSelect. |
|
1211 | * |
|
1212 | * @param name the search parameter key to retrieve. |
|
1213 | * @return the value of the search parameter. |
|
1214 | */ |
|
1215 | public String getSearchParam(String name) |
|
1216 | { |
|
1217 | 0 | return getSearchParam(name, null); |
1218 | } |
|
1219 | ||
1220 | /** |
|
1221 | * Retrieve a search parameter. This acts as a convenient place to store |
|
1222 | * parameters that relate to the LargeSelect to make it easy to get at them |
|
1223 | * in order to repopulate search parameters on a form when the next page of |
|
1224 | * results is retrieved - they in no way effect the operation of |
|
1225 | * LargeSelect. |
|
1226 | * |
|
1227 | * @param name the search parameter key to retrieve. |
|
1228 | * @param defaultValue the default value to return if the key is not found. |
|
1229 | * @return the value of the search parameter. |
|
1230 | */ |
|
1231 | public String getSearchParam(String name, String defaultValue) |
|
1232 | { |
|
1233 | 0 | if (null == params) |
1234 | { |
|
1235 | 0 | return defaultValue; |
1236 | } |
|
1237 | 0 | String value = (String) params.get(name); |
1238 | 0 | return null == value ? defaultValue : value; |
1239 | } |
|
1240 | ||
1241 | /** |
|
1242 | * Set a search parameter. If the value is <code>null</code> then the |
|
1243 | * key will be removed from the parameters. |
|
1244 | * |
|
1245 | * @param name the search parameter key to set. |
|
1246 | * @param value the value of the search parameter to store. |
|
1247 | */ |
|
1248 | public void setSearchParam(String name, String value) |
|
1249 | { |
|
1250 | 0 | if (null == value) |
1251 | { |
|
1252 | 0 | removeSearchParam(name); |
1253 | } |
|
1254 | else |
|
1255 | { |
|
1256 | 0 | if (null != name) |
1257 | { |
|
1258 | 0 | if (null == params) |
1259 | { |
|
1260 | 0 | params = new Hashtable(); |
1261 | } |
|
1262 | 0 | params.put(name, value); |
1263 | } |
|
1264 | } |
|
1265 | 0 | } |
1266 | ||
1267 | /** |
|
1268 | * Remove a value from the search parameters. |
|
1269 | * |
|
1270 | * @param name the search parameter key to remove. |
|
1271 | */ |
|
1272 | public void removeSearchParam(String name) |
|
1273 | { |
|
1274 | 0 | if (null != params) |
1275 | { |
|
1276 | 0 | params.remove(name); |
1277 | } |
|
1278 | 0 | } |
1279 | ||
1280 | /** |
|
1281 | * Deserialize this LargeSelect instance. |
|
1282 | * |
|
1283 | * @param inputStream The serialization input stream. |
|
1284 | * @throws IOException |
|
1285 | * @throws ClassNotFoundException |
|
1286 | */ |
|
1287 | private void readObject(ObjectInputStream inputStream) |
|
1288 | throws IOException, ClassNotFoundException |
|
1289 | { |
|
1290 | 0 | inputStream.defaultReadObject(); |
1291 | 0 | startQuery(pageSize); |
1292 | 0 | } |
1293 | ||
1294 | /** |
|
1295 | * Provide something useful for debugging purposes. |
|
1296 | * |
|
1297 | * @return some basic information about this instance of LargeSelect. |
|
1298 | */ |
|
1299 | public String toString() |
|
1300 | { |
|
1301 | 0 | StringBuffer result = new StringBuffer(); |
1302 | 0 | result.append("LargeSelect - TotalRecords: "); |
1303 | 0 | result.append(getTotalRecords()); |
1304 | 0 | result.append(" TotalsFinalised: "); |
1305 | 0 | result.append(getTotalsFinalized()); |
1306 | 0 | result.append("\nParameters:"); |
1307 | 0 | if (null == params || params.size() == 0) |
1308 | { |
|
1309 | 0 | result.append(" No parameters have been set."); |
1310 | } |
|
1311 | else |
|
1312 | { |
|
1313 | 0 | Set keys = params.keySet(); |
1314 | 0 | for (Iterator iter = keys.iterator(); iter.hasNext();) |
1315 | { |
|
1316 | 0 | String key = (String) iter.next(); |
1317 | 0 | String val = (String) params.get(key); |
1318 | 0 | result.append("\n ").append(key).append(": ").append(val); |
1319 | } |
|
1320 | } |
|
1321 | 0 | return result.toString(); |
1322 | } |
|
1323 | ||
1324 | } |
This report is generated by jcoverage, Maven and Maven JCoverage Plugin. |