1 | |
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2 | package de.ugoe.cs.autoquest.htmlmonitor; |
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3 | |
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4 | import java.io.File; |
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5 | import java.io.FileOutputStream; |
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6 | import java.io.IOException; |
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7 | import java.io.OutputStreamWriter; |
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8 | import java.io.PrintWriter; |
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9 | import java.text.DecimalFormat; |
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10 | |
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11 | /** |
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12 | * <p> |
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13 | * dumps messages to a log file belonging to a specific client id. In the provided base log |
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14 | * directory, it creates a subdirectory with the client id. In this directory it creates |
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15 | * appropriate log files. The name of each finished log file starts with the "htmlmonitor_" |
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16 | * followed by the client id and an index of the log file. An unfinished log file has no index yet. |
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17 | * A log file is finished if |
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18 | * <ul> |
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19 | * <li>the client session is closed by a timeout</li> |
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20 | * <li>the HTML monitor is normally shut down</li> |
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21 | * <li>on startup an unfinished log file is detected.</li> |
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22 | * <li>the {@link #MAXIMUM_LOG_FILE_SIZE} is reached</li> |
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23 | * </ul> |
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24 | * </p> |
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25 | * |
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26 | * @author Patrick Harms |
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27 | * @version 1.0 |
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28 | * |
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29 | */ |
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30 | public class HtmlMonitorOutputWriter implements HtmlMonitorComponent, HtmlMonitorMessageListener { |
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31 | |
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32 | /** |
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33 | * the maximum size of an individual log file |
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34 | */ |
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35 | private static final int MAXIMUM_LOG_FILE_SIZE = 10000000; |
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36 | |
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37 | /** |
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38 | * the default log base directory if none is provided through the constructor |
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39 | */ |
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40 | private static final String DEFAULT_LOG_FILE_BASE_DIR = "logs"; |
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41 | |
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42 | /** |
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43 | * the currently used log file base directory |
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44 | */ |
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45 | private File logFileBaseDir; |
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46 | |
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47 | /** |
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48 | * the is of the client of which all messages are logged through this writer |
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49 | */ |
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50 | private String clientId; |
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51 | |
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52 | /** |
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53 | * the log file into which all messages are currently written |
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54 | */ |
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55 | private File logFile; |
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56 | |
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57 | /** |
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58 | * an output writer to be used for writing into the log file |
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59 | */ |
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60 | private PrintWriter outputWriter; |
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61 | |
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62 | /** |
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63 | * the time stamp of the last action taken on this writer (such as logging a message) |
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64 | */ |
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65 | private long lastUpdate; |
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66 | |
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67 | /** |
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68 | * <p> |
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69 | * initializes the writer with the log file base directory and the id of the client for which |
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70 | * this writer logs the messages. |
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71 | * </p> |
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72 | * |
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73 | * @param logFileBaseDir the log file base directory, or null if the default directory shall |
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74 | * be taken |
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75 | * @param clientId the ID of the client, for which this writer logs |
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76 | */ |
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77 | public HtmlMonitorOutputWriter(String logFileBaseDir, String clientId) { |
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78 | if (logFileBaseDir == null) { |
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79 | this.logFileBaseDir = new File(DEFAULT_LOG_FILE_BASE_DIR); |
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80 | } |
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81 | else { |
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82 | this.logFileBaseDir = new File(logFileBaseDir); |
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83 | } |
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84 | |
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85 | this.clientId = clientId; |
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86 | |
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87 | lastUpdate = System.currentTimeMillis(); |
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88 | } |
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89 | |
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90 | /* (non-Javadoc) |
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91 | * @see de.ugoe.cs.autoquest.htmlmonitor.HtmlMonitorComponent#init() |
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92 | */ |
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93 | @Override |
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94 | public synchronized void init() throws HtmlMonitorException { |
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95 | if (outputWriter != null) { |
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96 | throw new IllegalStateException("already initialized. Call close() first"); |
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97 | } |
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98 | |
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99 | synchronized (HtmlMonitorOutputWriter.class) { |
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100 | try { |
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101 | File clientLogDir = new File(logFileBaseDir, clientId); |
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102 | |
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103 | if (!clientLogDir.exists()) { |
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104 | clientLogDir.mkdirs(); |
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105 | } |
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106 | else if (!clientLogDir.isDirectory()) { |
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107 | throw new HtmlMonitorException("client log file directory " + clientLogDir + |
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108 | " already exists as a file"); |
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109 | } |
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110 | |
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111 | logFile = new File(clientLogDir, getLogFileName(-1)); |
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112 | |
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113 | if (logFile.exists()) { |
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114 | rotateLogFile(); |
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115 | } |
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116 | |
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117 | createLogWriter(); |
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118 | } |
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119 | catch (IOException e) { |
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120 | throw new HtmlMonitorException("could not open logfile " + logFile, e); |
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121 | } |
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122 | } |
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123 | |
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124 | lastUpdate = System.currentTimeMillis(); |
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125 | } |
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126 | |
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127 | /** |
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128 | * <p> |
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129 | * used to calculate a log file name. If the provided index is smaller 0, then no index |
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130 | * is added to the file name. A filename is e.g. "htmlmonitor_12345_001.log". |
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131 | * </p> |
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132 | * |
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133 | * @param index the index of the log file or -1 one, if no index shall be added |
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134 | * |
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135 | * @return the file name as described |
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136 | */ |
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137 | private String getLogFileName(int index) { |
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138 | String result = "htmlmonitor_" + clientId; |
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139 | |
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140 | if (index >= 0) { |
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141 | result += "_" + new DecimalFormat("000" ).format(index); |
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142 | } |
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143 | |
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144 | result += ".log"; |
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145 | |
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146 | return result; |
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147 | } |
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148 | |
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149 | /* (non-Javadoc) |
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150 | * @see de.ugoe.cs.autoquest.htmlmonitor.HtmlMonitorComponent#start() |
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151 | */ |
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152 | @Override |
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153 | public synchronized void start() throws IllegalStateException, HtmlMonitorException { |
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154 | lastUpdate = System.currentTimeMillis(); |
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155 | } |
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156 | |
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157 | /* (non-Javadoc) |
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158 | * @see HtmlMonitorMessageListener#handleMessage(HtmlClientInfos, HtmlEvent[]) |
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159 | */ |
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160 | @Override |
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161 | public void handleMessage(HtmlClientInfos clientInfos, HtmlEvent[] events) { |
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162 | if (outputWriter == null) { |
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163 | throw new IllegalStateException("not initialized. Call init() first"); |
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164 | } |
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165 | |
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166 | for (HtmlEvent event : events) { |
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167 | dumpEvent(event); |
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168 | } |
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169 | |
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170 | outputWriter.flush(); |
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171 | |
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172 | try { |
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173 | considerLogRotate(); |
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174 | } |
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175 | catch (IOException e) { |
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176 | throw new IllegalStateException("could not perform log rotation: " + e, e); |
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177 | } |
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178 | |
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179 | lastUpdate = System.currentTimeMillis(); |
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180 | } |
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181 | |
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182 | /** |
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183 | * <p> |
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184 | * formats a received event and writes it to the log file. One event results in one line |
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185 | * in the log file containing all infos of the event. |
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186 | * </p> |
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187 | * |
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188 | * @param event to be written to the log file |
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189 | */ |
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190 | private void dumpEvent(HtmlEvent event) { |
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191 | dumpString(event.getClientInfos().getClientId()); |
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192 | outputWriter.print(' '); |
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193 | dumpString(event.getTime().toString()); |
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194 | outputWriter.print(' '); |
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195 | dumpString(event.getClientInfos().getTitle()); |
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196 | outputWriter.print(' '); |
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197 | dumpString(event.getClientInfos().getUrl().toString()); |
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198 | outputWriter.print(' '); |
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199 | dumpString(event.getClientInfos().getUserAgent()); |
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200 | outputWriter.print(' '); |
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201 | dumpString(event.getEventType()); |
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202 | outputWriter.print(' '); |
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203 | dumpString(event.getPath()); |
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204 | |
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205 | if (event.getCoordinates() != null) { |
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206 | outputWriter.print(' '); |
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207 | |
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208 | StringBuffer value = new StringBuffer(); |
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209 | for (int i = 0; i < event.getCoordinates().length; i++) { |
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210 | if (i > 0) { |
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211 | value.append(','); |
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212 | } |
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213 | value.append(event.getCoordinates()[i]); |
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214 | } |
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215 | |
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216 | dumpString(value.toString()); |
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217 | } |
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218 | |
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219 | if (event.getKey() != null) { |
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220 | outputWriter.print(' '); |
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221 | dumpString(event.getKey().toString()); |
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222 | } |
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223 | |
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224 | if (event.getScrollPosition() != null) { |
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225 | outputWriter.print(' '); |
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226 | dumpString(event.getScrollPosition().toString()); |
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227 | } |
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228 | |
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229 | outputWriter.println(); |
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230 | } |
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231 | |
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232 | /** |
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233 | * <p> |
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234 | * convenience method to dump a string with trailing and leading " as well as replaced |
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235 | * backslashes, ", and newlines |
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236 | * </p> |
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237 | * |
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238 | * @param clientId2 |
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239 | */ |
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240 | private void dumpString(String str) { |
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241 | outputWriter.print('"'); |
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242 | outputWriter.print |
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243 | (str.replaceAll("\\\\", "\\\\").replaceAll("\\\"", "\\\"").replaceAll("\n", " ")); |
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244 | outputWriter.print('"'); |
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245 | } |
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246 | |
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247 | /** |
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248 | * <p> |
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249 | * checks, if the log file exeeded the {@link #MAXIMUM_LOG_FILE_SIZE}. If so, the current |
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250 | * log file is closed, the next log file name is determined and this new file is opend for |
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251 | * writing. |
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252 | * </p> |
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253 | */ |
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254 | private synchronized void considerLogRotate() throws IOException { |
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255 | if (logFile.length() > MAXIMUM_LOG_FILE_SIZE) { |
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256 | closeLogWriter(); |
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257 | rotateLogFile(); |
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258 | createLogWriter(); |
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259 | } |
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260 | } |
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261 | |
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262 | /** |
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263 | * <p> |
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264 | * renames the current log file to a new log file with the next available index. It further |
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265 | * sets the current log file to the default name, i.e. without index. |
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266 | * </p> |
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267 | */ |
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268 | private void rotateLogFile() { |
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269 | File clientLogDir = logFile.getParentFile(); |
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270 | File checkFile; |
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271 | |
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272 | int logFileIndex = -1; |
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273 | do { |
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274 | logFileIndex++; |
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275 | |
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276 | checkFile = new File(clientLogDir, getLogFileName(logFileIndex)); |
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277 | } |
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278 | while (checkFile.exists()); |
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279 | |
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280 | logFile.renameTo(checkFile); |
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281 | logFileIndex++; |
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282 | logFile = new File(clientLogDir, getLogFileName(-1)); |
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283 | } |
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284 | |
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285 | /** |
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286 | * <p> |
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287 | * instantiates a writer to be used for writing messages into the log file. |
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288 | * </p> |
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289 | */ |
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290 | private void createLogWriter() throws IOException { |
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291 | FileOutputStream fis = new FileOutputStream(logFile); |
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292 | outputWriter = new PrintWriter(new OutputStreamWriter(fis, "UTF-8")); |
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293 | } |
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294 | |
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295 | /** |
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296 | * <p> |
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297 | * closed the current writer if it is open. |
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298 | * </p> |
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299 | */ |
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300 | private void closeLogWriter() { |
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301 | if (outputWriter != null) { |
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302 | outputWriter.flush(); |
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303 | outputWriter.close(); |
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304 | outputWriter = null; |
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305 | } |
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306 | } |
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307 | |
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308 | /* (non-Javadoc) |
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309 | * @see de.ugoe.cs.autoquest.htmlmonitor.HtmlMonitorComponent#stop() |
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310 | */ |
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311 | @Override |
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312 | public synchronized void stop() { |
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313 | closeLogWriter(); |
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314 | rotateLogFile(); |
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315 | |
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316 | lastUpdate = System.currentTimeMillis(); |
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317 | } |
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318 | |
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319 | /** |
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320 | * <p> |
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321 | * return the time stamp of the last activity that happened on this writer. |
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322 | * </p> |
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323 | * |
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324 | * @return as described |
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325 | */ |
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326 | public long getLastUpdate() { |
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327 | return lastUpdate; |
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328 | } |
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329 | } |
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