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1 /* |
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2 * Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of the License "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: |
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15 * |
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16 */ |
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17 |
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18 package com.nokia.carbide.cpp.internal.pi.manager; |
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19 |
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20 import java.util.Hashtable; |
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21 import java.util.Vector; |
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22 |
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23 /** |
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24 * A utility for predictively resolving classes |
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25 * This can be used to help offset one of the biggest detractors from |
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26 * the Java language: Class loading delays. |
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27 * |
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28 **/ |
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29 |
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30 public class BackgroundLoader implements Runnable |
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31 { |
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32 /** |
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33 * Thread used to load classes in the background |
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34 **/ |
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35 |
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36 private static Thread controlThread; |
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37 |
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38 /** |
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39 * Storage for the class names still to be resolved |
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40 **/ |
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41 |
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42 private static Vector queue; |
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43 |
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44 static |
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45 { |
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46 try |
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47 { |
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48 // This is an IBM-specific code that prevents a nasty error in the IBM resource lookup code -JDM |
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49 java.text.DateFormat.getDateInstance(); |
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50 } |
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51 catch (Exception e) |
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52 { |
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53 } |
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54 |
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55 queue = new Vector(); |
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56 } |
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57 |
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58 /** |
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59 * Private constructor, to enforce singleton status |
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60 * Creation date: (12/20/99 3:10:32 PM) |
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61 **/ |
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62 |
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63 private BackgroundLoader() |
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64 { |
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65 } |
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66 |
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67 /** |
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68 * Enqueue a class for background loading |
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69 * Creation date: (12/20/99 3:23:28 PM) |
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70 * @param className java.lang.String |
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71 **/ |
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72 |
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73 public static void enqueueClass(String className) |
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74 { |
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75 synchronized(queue) |
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76 { |
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77 queue.addElement(className); |
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78 |
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79 if (controlThread == null) |
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80 start(); |
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81 else |
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82 queue.notify(); |
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83 } |
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84 } |
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85 |
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86 /** |
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87 * Start loading |
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88 * Creation date: (12/20/99 3:15:29 PM) |
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89 **/ |
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90 |
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91 public void run() |
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92 { |
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93 if (Thread.currentThread() != controlThread) |
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94 return; |
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95 |
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96 Hashtable done = new Hashtable(); |
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97 |
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98 while (controlThread.isAlive()) |
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99 { |
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100 String className; |
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101 |
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102 synchronized(queue) |
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103 { |
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104 if (queue.isEmpty()) |
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105 { |
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106 try |
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107 { |
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108 queue.wait(); |
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109 } |
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110 catch (InterruptedException ie) |
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111 { |
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112 } |
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113 } |
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114 |
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115 if (!queue.isEmpty()) |
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116 { |
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117 className = (String) queue.elementAt(0); |
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118 queue.removeElementAt(0); |
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119 } |
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120 else |
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121 continue; |
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122 } |
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123 |
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124 if (!done.containsKey(className)) |
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125 { |
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126 try |
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127 { |
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128 Class resolved = Class.forName(className); |
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129 done.put(resolved.getName(), resolved); |
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130 } |
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131 catch (Exception e) |
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132 { |
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133 e.printStackTrace(); |
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134 } |
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135 } |
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136 |
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137 className = null; |
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138 } |
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139 |
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140 controlThread = null; |
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141 } |
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142 |
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143 /** |
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144 * Insert the method's description here. |
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145 * Creation date: (4/5/00 3:24:04 PM) |
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146 */ |
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147 |
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148 private static void start() |
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149 { |
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150 controlThread = new Thread(new BackgroundLoader()); |
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151 |
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152 try |
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153 { |
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154 controlThread.setName(Messages.getString("BackgroundLoader.backgroundLoader")); //$NON-NLS-1$ |
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155 controlThread.setPriority((Thread.MIN_PRIORITY + Thread.NORM_PRIORITY) / 2); |
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156 } |
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157 catch (Exception e) |
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158 { |
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159 } |
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160 |
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161 controlThread.start(); |
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162 } |
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163 } |