1 /* |
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2 * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 |
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27 |
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28 package sun.misc; |
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29 |
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30 import java.util.Vector; |
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31 import java.io.FileWriter; |
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32 import java.io.File; |
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33 import java.io.OutputStreamWriter; |
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34 import java.io.Writer; |
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35 |
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36 /** |
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37 * This class is intended to be a central place for the jdk to |
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38 * log timing events of interest. There is pre-defined event |
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39 * of startTime, as well as a general |
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40 * mechanism of setting arbitrary times in an array. |
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41 * All unreserved times in the array can be used by callers |
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42 * in application-defined situations. The caller is responsible |
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43 * for setting and getting all times and for doing whatever |
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44 * analysis is interesting; this class is merely a central container |
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45 * for those timing values. |
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46 * Note that, due to the variables in this class being static, |
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47 * use of particular time values by multiple applets will cause |
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48 * confusing results. For example, if plugin runs two applets |
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49 * simultaneously, the initTime for those applets will collide |
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50 * and the results may be undefined. |
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51 * <P> |
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52 * To automatically track startup performance in an app or applet, |
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53 * use the command-line parameter sun.perflog as follows:<BR> |
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54 * <pre>{@code |
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55 * -Dsun.perflog[=file:<filename>] |
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56 * }</pre> |
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57 * <BR> |
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58 * where simply using the parameter with no value will enable output |
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59 * to the console and a value of "{@code file:<filename>}" will cause |
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60 * that given filename to be created and used for all output. |
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61 * <P> |
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62 * By default, times are measured using System.currentTimeMillis(). To use |
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63 * System.nanoTime() instead, add the command-line parameter:<BR> |
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64 -Dsun.perflog.nano=true |
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65 * <BR> |
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66 * <P> |
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67 * <B>Warning: Use at your own risk!</B> |
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68 * This class is intended for internal testing |
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69 * purposes only and may be removed at any time. More |
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70 * permanent monitoring and profiling APIs are expected to be |
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71 * developed for future releases and this class will cease to |
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72 * exist once those APIs are in place. |
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73 * @author Chet Haase |
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74 */ |
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75 public class PerformanceLogger { |
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76 |
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77 // Timing values of global interest |
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78 private static final int START_INDEX = 0; // VM start |
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79 private static final int LAST_RESERVED = START_INDEX; |
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80 |
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81 private static boolean perfLoggingOn = false; |
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82 private static boolean useNanoTime = false; |
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83 private static Vector<TimeData> times; |
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84 private static String logFileName = null; |
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85 private static Writer logWriter = null; |
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86 private static long baseTime; |
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87 |
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88 static { |
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89 String perfLoggingProp = |
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90 java.security.AccessController.doPrivileged( |
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91 new sun.security.action.GetPropertyAction("sun.perflog")); |
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92 if (perfLoggingProp != null) { |
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93 perfLoggingOn = true; |
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94 |
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95 // Check if we should use nanoTime |
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96 String perfNanoProp = |
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97 java.security.AccessController.doPrivileged( |
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98 new sun.security.action.GetPropertyAction("sun.perflog.nano")); |
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99 if (perfNanoProp != null) { |
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100 useNanoTime = true; |
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101 } |
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102 |
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103 // Now, figure out what the user wants to do with the data |
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104 if (perfLoggingProp.regionMatches(true, 0, "file:", 0, 5)) { |
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105 logFileName = perfLoggingProp.substring(5); |
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106 } |
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107 if (logFileName != null) { |
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108 if (logWriter == null) { |
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109 java.security.AccessController.doPrivileged( |
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110 new java.security.PrivilegedAction<Void>() { |
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111 public Void run() { |
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112 try { |
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113 File logFile = new File(logFileName); |
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114 logFile.createNewFile(); |
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115 logWriter = new FileWriter(logFile); |
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116 } catch (Exception e) { |
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117 System.out.println(e + ": Creating logfile " + |
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118 logFileName + |
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119 ". Log to console"); |
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120 } |
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121 return null; |
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122 } |
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123 }); |
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124 } |
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125 } |
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126 if (logWriter == null) { |
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127 logWriter = new OutputStreamWriter(System.out); |
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128 } |
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129 } |
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130 times = new Vector<TimeData>(10); |
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131 // Reserve predefined slots |
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132 for (int i = 0; i <= LAST_RESERVED; ++i) { |
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133 times.add(new TimeData("Time " + i + " not set", 0)); |
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134 } |
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135 } |
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136 |
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137 /** |
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138 * Returns status of whether logging is enabled or not. This is |
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139 * provided as a convenience method so that users do not have to |
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140 * perform the same GetPropertyAction check as above to determine whether |
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141 * to enable performance logging. |
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142 */ |
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143 public static boolean loggingEnabled() { |
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144 return perfLoggingOn; |
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145 } |
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146 |
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147 |
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148 /** |
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149 * Internal class used to store time/message data together. |
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150 */ |
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151 static class TimeData { |
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152 String message; |
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153 long time; |
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154 |
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155 TimeData(String message, long time) { |
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156 this.message = message; |
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157 this.time = time; |
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158 } |
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159 |
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160 String getMessage() { |
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161 return message; |
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162 } |
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163 |
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164 long getTime() { |
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165 return time; |
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166 } |
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167 } |
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168 |
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169 /** |
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170 * Return the current time, in millis or nanos as appropriate |
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171 */ |
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172 private static long getCurrentTime() { |
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173 if (useNanoTime) { |
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174 return System.nanoTime(); |
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175 } else { |
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176 return System.currentTimeMillis(); |
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177 } |
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178 } |
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179 |
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180 /** |
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181 * Sets the start time. Ideally, this is the earliest time available |
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182 * during the startup of a Java applet or application. This time is |
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183 * later used to analyze the difference between the initial startup |
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184 * time and other events in the system (such as an applet's init time). |
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185 */ |
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186 public static void setStartTime(String message) { |
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187 if (loggingEnabled()) { |
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188 long nowTime = getCurrentTime(); |
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189 setStartTime(message, nowTime); |
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190 } |
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191 } |
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192 |
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193 /** |
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194 * Sets the base time, output can then |
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195 * be displayed as offsets from the base time;. |
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196 */ |
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197 public static void setBaseTime(long time) { |
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198 if (loggingEnabled()) { |
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199 baseTime = time; |
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200 } |
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201 } |
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202 |
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203 /** |
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204 * Sets the start time. |
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205 * This version of the method is |
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206 * given the time to log, instead of expecting this method to |
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207 * get the time itself. This is done in case the time was |
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208 * recorded much earlier than this method was called. |
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209 */ |
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210 public static void setStartTime(String message, long time) { |
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211 if (loggingEnabled()) { |
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212 times.set(START_INDEX, new TimeData(message, time)); |
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213 } |
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214 } |
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215 |
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216 /** |
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217 * Gets the start time, which should be the time when |
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218 * the java process started, prior to the VM actually being |
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219 * loaded. |
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220 */ |
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221 public static long getStartTime() { |
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222 if (loggingEnabled()) { |
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223 return times.get(START_INDEX).getTime(); |
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224 } else { |
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225 return 0; |
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226 } |
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227 } |
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228 |
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229 /** |
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230 * Sets the value of a given time and returns the index of the |
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231 * slot that that time was stored in. |
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232 */ |
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233 public static int setTime(String message) { |
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234 if (loggingEnabled()) { |
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235 long nowTime = getCurrentTime(); |
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236 return setTime(message, nowTime); |
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237 } else { |
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238 return 0; |
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239 } |
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240 } |
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241 |
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242 /** |
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243 * Sets the value of a given time and returns the index of the |
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244 * slot that that time was stored in. |
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245 * This version of the method is |
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246 * given the time to log, instead of expecting this method to |
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247 * get the time itself. This is done in case the time was |
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248 * recorded much earlier than this method was called. |
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249 */ |
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250 public static int setTime(String message, long time) { |
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251 if (loggingEnabled()) { |
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252 // times is already synchronized, but we need to ensure that |
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253 // the size used in times.set() is the same used when returning |
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254 // the index of that operation. |
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255 synchronized (times) { |
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256 times.add(new TimeData(message, time)); |
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257 return (times.size() - 1); |
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258 } |
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259 } else { |
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260 return 0; |
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261 } |
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262 } |
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263 |
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264 /** |
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265 * Returns time at given index. |
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266 */ |
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267 public static long getTimeAtIndex(int index) { |
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268 if (loggingEnabled()) { |
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269 return times.get(index).getTime(); |
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270 } else { |
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271 return 0; |
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272 } |
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273 } |
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274 |
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275 /** |
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276 * Returns message at given index. |
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277 */ |
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278 public static String getMessageAtIndex(int index) { |
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279 if (loggingEnabled()) { |
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280 return times.get(index).getMessage(); |
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281 } else { |
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282 return null; |
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283 } |
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284 } |
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285 |
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286 /** |
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287 * Outputs all data to parameter-specified Writer object |
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288 */ |
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289 public static void outputLog(Writer writer) { |
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290 if (loggingEnabled()) { |
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291 try { |
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292 synchronized(times) { |
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293 for (int i = 0; i < times.size(); ++i) { |
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294 TimeData td = times.get(i); |
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295 if (td != null) { |
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296 writer.write(i + " " + td.getMessage() + ": " + |
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297 (td.getTime() - baseTime) + "\n"); |
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298 |
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299 } |
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300 } |
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301 } |
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302 writer.flush(); |
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303 } catch (Exception e) { |
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304 System.out.println(e + ": Writing performance log to " + |
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305 writer); |
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306 } |
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307 } |
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308 } |
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309 |
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310 /** |
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311 * Outputs all data to whatever location the user specified |
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312 * via sun.perflog command-line parameter. |
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313 */ |
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314 public static void outputLog() { |
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315 outputLog(logWriter); |
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316 } |
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317 } |
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